detector technologies group 2018 ep-dt
TRANSCRIPT
1
Detector Technologies Group
EP-DT 2018
This report gives a summary of the mandate, structure and activities of the EP-DT group during the year 2018.
ANNUAL REPORT
©CERN, June 2019
3
Table of Contents
1. DT MANDATE AND ORGANIZATION 5
2. COLLABORATIONS WITH LHC EXPERIMENTS 11
2.1. ALICE 11 ALICE DETECTOR UPGRADE 11 NEW CENTRAL DETECTORS AND OVERALL LS2 WORK PLAN 14
2.2. ATLAS UPGRADE 15 PHASE I: MICROMEGAS FOR THE NEW SMALL WHEEL 15 PHASE II: INNER TRACKER PIXEL UPGRADE 16
2.3. CMS UPGRADE 20 CMS TRACKER UPGRADE 20 CMS HIGH GRANULARITY CALORIMETER 22
2.4. LHCB UPGRADE 23 VELO UPGRADE 23 UPSTREAM TRACKER 25 SCINTILLATING FIBRE TRACKER 26 RICH AND TORCH 28 MUON SYSTEM 28 UPGRADE PREPARATION AND INTEGRATION STUDIES 29
3. COLLABORATIONS WITH NON-LHC EXPERIMENTS 31
3.1. CLOUD 31 3.2. NA62 32
DATA TAKING & RESULTS 32 DETECTOR OPERATION & MAINTENANCE 32 GIGATRACKER MODULE PREPARATION 33
3.3. ISOLDE 34
4. PROJECTS UNDER STUDY 35
4.1. LINEAR COLLIDER DETECTOR PROJECT 35 R&D FOR HIGHLY GRANULAR CALORIMETERS 35
4.2. NEUTRINO PLATFORM 36 ENGINEERING STUDIES FOR THE NEUTRINO EXPERIMENTS 36 DAQ, CONTROL AND SAFETY SYSTEMS 37
4.3. SEARCH FOR HIDDEN PARTICLES: SHIP 40
5. R&D ON EXPERIMENTAL TECHNOLOGIES 41
5.1. RADIATION TOLERANT SILICON DETECTORS 41 5.2. CMOS PIXEL R&D 43 5.3. MICRO-PATTERN GAS DETECTORS 44 5.4. R&D FOR CO2 COOLING 47
ON-DETECTOR COOLING R&D 47 COOLING SYSTEM R&D 49 OPTICAL FIBRE THERMO-HYGROMETRY 50
5.5. R&D ON GAS SYSTEMS 51 5.6. MICROFABRICATION TECHNOLOGIES 53
6. SERVICES PROVIDED BY DT 55
4
6.1. GAS SYSTEMS 55 6.2. CO2 COOLING SYSTEMS 56
COOLING COORDINATION WITH LHC EXPERIMENTS 56 CONSTRUCTION OF NEW COOLING PLANTS 56
6.3. MAGNETIC MEASUREMENTS AND CONTROLS 58 MAGNETIC FIELD MEASUREMENT SERVICE 58 MAGNET CONTROL AND SAFETY SYSTEM 59 INSTRUMENTATION AND CONTROLS 60
6.4. DAQ SYSTEMS 62
7. INFRASTRUCTURE FOR DETECTOR R&D 64
7.1. IRRADIATION FACILITIES 64 GAMMA IRRADIATION FACILITY (GIF++) AT THE SPS NORTH AREA 64 PROTON (IRRAD) & MIXED‐FIELD (CHARM) IRRADIATION FACILITIES AT PS EAST AREA 66 RADIATION MONITORING SENSORS (RADMON) 68
7.2. SOLID STATE DETECTOR LAB, BOND LAB, QART LAB AND DSF 68 SOLID STATE DETECTOR LAB 68 BOND LAB 69 QUALITY ASSURANCE AND RELIABILITY TESTING (QART) LAB 70 DEPARTMENTAL SILICON FACILITY (DSF) 71
7.3. THIN FILM AND GLASS LAB 71 7.4. SCINTILLATOR LAB AND WORKSHOP 73 7.5. COMPOSITE LAB 73 7.6. MICRO PATTERN TECHNOLOGIES WORKSHOP 75
LARGE GEM MASS PRODUCTIONS 75 MACHINE INSTALLATION PROGRAM IN BUILDING 107 76 ALUMINIUM BUS PRODUCTION FOR THE ALICE INNER TRACKER 77
8. SAFETY IN EP-DT 78
9. SECRETARIAT 79
10. SELECTED PUBLICATIONS AND CONTRIBUTIONS TO CONFERENCES 79
5
1. DT Mandate and Organization Burkhard Schmidt
The Detector Technologies (DT) group in the Experimental Physics department participates in the development, construction, operation and maintenance of particle detectors for experiments at CERN. The group is engaged in several detector projects for LHC and non-LHC experiments, operates services open to all CERN users for detector operation, research & development, and is involved in R&D projects on new detector technologies and related infrastructures. Expertise in many different domains crucial for advanced detector-systems is available in the DT group. Among these are engineering, fine mechanics and micro-fabrication, thin film coatings and optics, a silicon facility with a wire-bonding and quality assurance lab, irradiation facilities, gas and cooling systems for particle detectors, magnet control and safety systems for experiments, magnetic field measurements, data acquisition and control systems. DT runs several mechanical workshops with conventional and CNC machines and equipment for specialized machining for scintillators, glass and ceramics. The main EP-DT activities are organized in three main categories:
Services for developing and operating infrastructures for experiments and detector R&D. They are available for all experiments at CERN. They offer a coherent, ready-to-use deliverable (e.g. a gas or CO2 cooling system, a control or DAQ system, etc.), support for maintenance and operation, advice and consultancy.
R&D projects on strategic fields related to new detector technologies and detector infrastructures that are of common interest for all experiments. They include in particular radiation tolerant silicon detectors and micro pattern gas detectors. For both of these projects a host lab environment for external partners is also provided.
Joint Projects with experimental teams in CERN experiments to develop, construct and operate particle detectors. Joint projects are set up for a defined amount of time and the scope of the collaboration is described in dedicated work package agreements.
In 2018, about 46% of the staff resources were allocated to projects; about 45% of the group provided service activities and 5% carried out R&D related work, including leadership of R&D
Services Infrastructure for experiments: Gas systems
Detector cooling systems
DAQ and control systems
Magnet control and safety systems
Magnetic field measurements
Infrastructure for Detector R&D: Thin film & glass Lab
Silicon facility
Wire-bonding & QART Lab
Micro-Pattern Technologies
Irradiation facilities
Specialized labs (optics, etc.)
Scintillator lab
Engineering office
R&D Projects
Radiation tolerant silicon detectors (RD-50)
CMOS Pixel detectors
Gaseous detectors (RD-51)
Scintillating fibre detectors
Novel on-detector cooling
Micro-system engineering
Joint Projects
M&O and Upgrades of the LHC experiments
CLOUD, NA62
Linear Collider Detector study, Neutrino Platform experiments, SHiP detector study
6
collaborations and EU co-funded projects. Finally, about 4% of the group’s resources are engaged in safety tasks, participation to CERN-wide committees and the management of the group.
7
In 2018 the DT group had about 85 active Staff; 33 members who are Fellows, Project or Cooperation Associates; 16 members who are Doctoral or Technical Students and on average 12 Trainees or participants to the Technical Training Experience (TTE) programme. Besides the staff, all other categories are partially funded through other groups of the EP department. DT hosts also two Field Support Units (FSU PH-02 and PH-40) with in total 32 members. The DT group structure remained stable over the past year and only minor adjustments have been implemented. They include the strengthening of the DAQ and DCS support the group provided in particular to small and medium size experiments. The present structure:
i) optimizes the support to the experiments in the phase 2018-2026, where demanding detector R&D and prototyping for LHC Phase II upgrade projects overlaps with the finalization of the construction and installation of LHC Phase I upgrade projects and the preparation of new experiments and studies;
ii) enhances flexibility by providing centralized expertise to exploit specialist experience at its maximum potential in particular in the area of services;
iii) preserves and promotes current efforts on detector R&D and drives a culture of innovation of novel technologies and related infrastructures;
iv) maintains know-how and ensures successful careers of DT technical staff. Several members of the group have been strongly involved in the process of defining a new strategic R&D programme on experimental technologies, launched by the CERN EP department. The programme covers the domains of detectors, electronics and software and intimately connected systems such as mechanics, cooling and experimental magnets. DT members contributed in particular in the areas of Silicon Detectors, Gas based Detectors and Detector mechanics and cooling. A report has been prepared [1]1 and submitted for the update of the European Strategy for Particle Physics. DT staff is currently grouped in seven sections, with the following mandates:
Technology and Physics: physicists and engineers in this section participate in experiments at CERN, both at the LHC and at smaller facilities. They take a leading role in the upgrade of the LHC detectors and various studies for future projects. They also ensure the direct contact between their experiments for all activities of the group.
1 The numbers in brackets refer to selected publications given in section 10 of the report
8
The section Detector Development contributes to detector projects in collaboration with experimental teams. It is deeply involved in the RD50 (Radiation Tolerant Silicon Detectors) and RD51 (Micro-Pattern Gas Detectors) collaborations by contributions to the R&D program as well as providing managerial and organizational support. The section operates state of the art services for detector R&D: the departmental Silicon Facility with the wire bonding and interconnect facility, the quality and reliability assurance lab and the EP irradiation facilities.
The Fluidic Systems section mandate is to design, prototype, construct, commission, operate and maintain fluidic systems (gas & cooling) for detectors in CERN experiments. It performs selective R&D in areas relevant to novel detector thermal management, gas systems, and for the upgrade of the existing systems in view of higher detector performances and sustainable operation.
The Detector Interface section combines the long lasting EP-DT expertise in control and safety systems for the infrastructure of experiments with the support for data acquisition and monitoring systems, targeting mainly small- and mid-scale experiments and projects. Progress has been made in the past year to create a combined environment for controls and DAQ to be offered to the experiments requesting it.
The Engineering Facilities section mandate is to provide to the CERN community specific solutions combining mechanical design, small-scale production and prototyping facilities and test benches for the core technologies of particle detectors at CERN. It includes the Thin-Film lab and the Micro-Pattern-Technology workshop.
The Engineering Office section is in charge of mechanical design activities for detector-related projects. Designers and engineers cover a wide range of disciplines in mechanical engineering, construction, and numerical simulations. The core competencies include 3D modelling and drafting, integration studies, structural and thermal analyses, fluid-dynamics and structural verifications according to relevant standards and codes.
Detector Construction & Operations provides to the CERN community specific solutions combining mechanical design, prototyping and small-scale production of particle detector systems and support the operation of CERN experiments.
Often, project work is carried out in teams formed for a limited time, frequently with people from several sections and led by a DT project leader. Such teams include also fellows, students and scientists associated to DT. This strategy offers flexibility, efficiency and a fast reaction time for new requests and activity changes. The organigrams shown in pages 9 and 10 show the DT members as of May 2019. The graph below shows the DT staff category composition.
Further information about the DT group is available at http://ep-dep-dt.web.cern.ch
9
Ma
y 2
01
9
GU
IDA
Ro
ber
to (
Gas
PL)
PET
AG
NA
(C
oo
ling
PL)
C
AR
RIE
Pat
rick
D
AG
UIN
Jer
om
e D
'AU
RIA
An
dre
a D
E M
ENEZ
ES L
ou
is-P
hili
pp
e G
IAK
OU
MI D
ina
KA
PU
SNIA
K K
acp
er
MA
ND
ELLI
Bea
tric
e
MER
LET
Fred
eric
N
OE
L J
ero
me
VER
LAA
T B
art
ZIM
NY
Mic
hal
ZW
AL
INSK
I L
uk
asz
AL
VIG
NI
L (
TR
NE
) B
ER
RU
TI
G (
CO
AS)
B
HA
NO
T V
(C
OA
S)
CH
OL
EW
A M
(TR
NE
) C
ON
SAL
ES
M (
CO
AS)
C
OR
BE
TT
A M
ara
(T
ech
) C
USA
NO
A (
CO
AS)
D
AV
OIN
E L
(F
ell)
G
AL
UK
SA S
(C
OA
S)
GR
AZ
IAN
I L
(F
ell)
HU
LE
K W
(T
ech
) K
OSS
N (
Fel
l)
LO
EP
Z M
AC
IA P
(P
JAS)
P
AK
UL
SKI
T (
Fel
l)
PIE
KN
IK M
(T
RN
E)
PIM
EN
TE
L T
(D
oct
) P
UE
NT
E R
ICO
R (
PJA
S)
RIG
OL
ET
TI
G (
Do
ct)
UN
IT1
BE
ND
OT
TI
Jero
me
DIX
ON
Nei
l D
UM
PS
Rap
hae
l K
OT
TE
LA
T L
uc-
Jose
ph
KR
IST
IC R
ob
ert
LOO
S R
ob
ert
PER
EZ G
OM
EZ F
ran
cisc
o
PIE
DIG
RO
SSI D
idie
r U
NIT
2
AN
STE
TT
Did
ier
Hen
ri
BO
UV
IER
Ph
ilip
pe
Jacq
ues
IJ
ZE
RM
AN
S P
iete
r L
AH
U G
rego
ry
LE
SEN
EC
HA
L Y
ann
ick
VA
N B
EE
LE
N J
aco
b
Bas
tiaa
n
CIC
HY
K (
Fel
l)
FE
RR
O-L
UZ
ZI
S (T
RN
E)
FIL
EN
IUS
A (
TR
NE
) M
AK
HA
RIN
SKY
D (
Tec
h)
MA
NN
INE
N H
(F
ell)
M
UN
OZ
J (
Tec
h)
PF
EIF
ER
J (
Fel
l)
PIA
ZZ
A Q
(T
TE
) R
EA
LE
S G
(T
ech
) SR
OK
A S
(T
RN
E)
WE
BE
R S
(F
ell)
De
tect
or
Co
nst
ruct
ion
&
Op
era
tio
ns
(DT-
CO
) A
ntt
i ON
NEL
A
Dep
uty
: F.P
EREZ
EP-D
T D
ete
cto
r Te
chn
olo
gie
s
Gro
up
lead
er:
Bu
rkh
ard
SC
HM
IDT
De
pu
tie
s: A
nd
rea
CA
TIN
AC
CIO
& M
ich
ael M
OLL
Se
cret
ari
at:
Ver
on
iqu
e W
EDLA
KE
De
sign
ro
om
B
AU
LT C
hri
sto
ph
e (P
L)
DEG
RA
NG
E Jo
rdan
JA
MET
Oliv
ier
LEN
OIR
Ph
ilip
pe
PER
EZ A
lexa
nd
re
De
sign
an
d A
nal
ysis
A
LVA
REZ
Die
go
BA
TIST
A J
oao
Car
los
GA
RG
IULO
Co
rrad
o
H
ATC
H M
ark
Co
mp
osi
te L
ab
BO
YER
Fra
nço
is
AN
GEL
ETTI
M (
Do
ct)
ESA
LA J
(Fe
ll)
FAV
RE
P (
TRN
E)
MO
HA
MA
DI D
(TR
NE)
SC
HM
IDT
Ma
nu
el (
TRN
E)
SLIW
A K
(P
JAS)
Engi
nee
rin
g O
ffic
e (D
T-EO
) A
nd
rea
CA
TIN
AC
CIO
D
epu
ty: C
. BA
ULT
Silic
on
De
t R
&D
MO
LL M
ich
ael (
PL)
C
OST
AN
ZI
Ru
dd
y L
A R
OSA
Ale
ssan
dro
M
AN
OLE
SCU
Flo
ren
tin
a M
AP
EL
LI
Ale
ssan
dro
M
CG
ILL
Ian
ALL
EGR
ETTI
S (
PJA
S)
CA
LLEG
AR
I R (
Fell)
C
AR
RA
SCO
A (
TR
NE
) C
AR
BA
LA R
(TR
NE)
C
AR
DEL
LA R
(Fe
ll)
CEN
TIS
M (
Fell)
FR
EI T
(D
oct
) G
UR
IMSK
AYA
Y (
Fell)
H
ALV
OR
SEN
M (
Tech
) H
EYM
AN
S G
(TR
NE)
M
ATE
U I
(TR
N F
TEC
) U
DES
EN S
(TR
NE)
W
IEH
E M
(D
oct
)
G
as D
et
R&
D
RO
PEL
EWSK
I Les
zek
(PL)
O
LIV
ERI E
rald
o
BR
UN
BA
UER
F (
Fell)
Irra
dia
tio
n F
acili
tie
s R
AV
OTT
I Fed
eric
o (
PL)
JA
EKEL
Mar
tin
PEZ
ZULO
Giu
sep
pe
GO
TKSE
B (
CO
AS)
LA
RSE
N J
(TR
NE)
De
tect
or
De
velo
pm
en
t (D
T-D
D)
Pet
ra R
IED
LER
Flu
idic
Sys
tem
s (D
T-FS
) P
aola
TR
OP
EA
Engi
nee
rin
g Fa
cilit
ies
(DT-
EF)
Han
s D
AN
IELS
SON
D
epu
ty: P
A.G
IUD
ICI
Thin
Film
& G
lass
SC
HN
EID
ER T
ho
mas
(P
L)
VA
N S
TEN
IS M
iran
da
Mic
ro-P
att
ern
Te
ch
DE
OL
IVE
IRA
Ru
i (P
L)
FE
RR
Y S
erge
G
RIS
Ale
xan
dra
M
EH
L B
ertr
and
PIZ
ZIR
USS
O O
livi
er
RA
NC
HIN
Dav
id
RO
DR
IGU
ES
Ale
xis
TE
IXE
IRA
An
ton
io
WIL
LIA
MS
Sim
on
Mac
hin
e S
ho
ps
GA
RN
IER
Fra
nco
is
GIU
DIC
I P
ierr
e-A
nge
G
ON
GA
LV
ES
An
ton
io
KE
RE
KE
S Z
olt
an
Ma
gn
ets
su
pp
ort
B
ER
GSM
A F
elix
(P
L)
BO
NN
AR
D R
(F
ell)
)
GYS
Th
ierr
y
JAK
OB
SEN
Su
ne
MA
RTI
NEN
GO
Pao
lo
PA
CIF
ICO
Nic
ola
SI
CK
ING
Eva
W
ERTE
LAER
S P
iet
Tech
no
logy
& P
hys
ics
(DT-
TP)
Bu
rkh
ard
SC
HM
IDT
PO
NS
Xav
ier
BLA
NC
Pas
cal
BO
UR
GEO
IS N
ico
las
DER
ON
T La
ure
nt
GA
MB
ERIN
I En
rico
M
END
EZ P
atri
cia
OST
REG
A M
acie
j SI
PO
S R
ola
nd
BO
NIN
I F
ilib
erto
(T
ech
) B
OR
ET
TO
M (
Do
ct)
BR
YL
INSK
I W
(D
oct
) C
ICA
LE
SE D
(F
ell)
MA
DE
RA
Alf
onso
(D
oct
) M
AL
AG
UT
I G
(F
ell)
N
AP
OL
EO
NI
M (
TR
NE
)
De
tect
or
Inte
rfac
e
(DT-
DI)
Gio
van
na
LEH
MA
NN
D
epu
ty: X
. PO
NS
Pro
ject
s
Serv
ice
s
FSU
PH
40
: A.D
rozd
, K.B
aran
, F.B
eden
do
, E.B
ud
un
, T.B
ud
un
, G.B
utt
on
, P
.Du
ber
t, K
.Jau
regu
i, B
.Mar
tin
s, P
.Ngu
yen
, E.P
ech
aud
, J.P
ened
o, X
.Th
ery
FSU
PH
02
: A.K
ehrl
i, M
.Car
rich
on
, C.C
ot,
G.C
rep
et, B
.Din
ger,
J.D
um
olla
rd,
A.L
aass
iri,
B.L
acar
elle
, C.L
and
rau
d, H
.Mar
tin
ati,
I.M
org
adin
ho
, S.R
amb
aut,
B
.Van
Do
nk.
10
ad
dit
ion
al p
erso
ns
wo
rk f
or
oth
er
gro
up
s.
SCH
ER
INO
L (
Do
ct)
SCH
MID
Da
vid
(D
oct
) U
RB
AN
SKA
K (
TR
NE
) Z
HU
RA
VL
OV
A A
(T
ech
)
10
11
2. Collaborations with LHC Experiments
2.1. ALICE Corrado Gargiulo
ALICE Detector Upgrade
The ALICE upgrade program has entered in 2018 in its crucial phase. The planned upgrade includes a new beampipe with a smaller diameter, a new Inner Tracking System (ITS), a vertex tracker for forward muons (MFT), the upgrade of the Time Projection Chamber (TPC) with GEM detectors, the upgrade of the forward trigger detectors and the upgrade of the online and offline system. The ALICE upgrade strategy is based on the plan that, after the second long LHC shutdown in 2019-20, the luminosity with lead beams will gradually increase to an interaction rate of about 50 kHz, about two orders of magnitude higher than the current readout rate capability. In order to cope with the increased readout rate, the readout electronics of nearly all the ALICE detectors will have to be re-designed.
Beam pipe The new beampipe, is under production at Materion Electrofusion in Fremont, California. Production follow up is a close collaboration between the ALICE DT engineering team and the CERN Vacuum group VSC. All beampipe sections, including the beryllium one, have been produced and are now being welded together. The assembled beampipe will be shipped to CERN for the cleaning and etching process critical for the NEG adhesion. The beampipe, will then undergo to full qualification, including vacuum acceptance tests, to be ready for the installation with contingency of few months. Inner Tracking System The upgraded ITS will improve the track position resolution at the primary vertex by a factor of 3 in r-phi and even more in z with respect to the present detector. Monolithic pixel sensors and special carbon fibre support structures characterize the ITS upgrade as an ultra-light seven layer 12GigaPixel detector that will allow a significant boost of the tracking performance.
ALICE ITS Inner Half-Layer 2, assembly of 10 staves 300mm in length
2018 has been the year of the stave mass production, based on stave component production and stave assembly. Parallel production lines have fed the five stave construction sites worldwide with chips, flex printed circuit (FPC), power busses and carbon supports.
12
The entire ALPIDE sensors production, their thinning and dicing, under DT responsibility has been finalized. In the DT Micro-pattern Technologies workshop, the full production of the aluminium FPC for the three innermost layers of the ITS has been also completed. The DT Silicon Facility has provided a fundamental support in the wire bonding interconnection between the chip and the FPC, as well in the full characterization of the assembled staves. The mass production of the staves’ ultralight carbon structures, based at CERN in the ALICE Composite Laboratory, under DT responsibility, has been finalized and the parts have been shipped to the construction sites.
The staves assembly has started at the beginning of 2018 at CERN for the Inner Layers, and at the five stave construction sites in Europe and in the United States for the Outer Layers. The ALICE DT technical team has a primary responsibility in the different assembly phases of the staves in layers that is taking place in the ALICE clean room in building 167. The three inner layers have been completed and are under test, while a full spare set of layers is also almost ready. For the ITS outer layers, the half barrel is completed and is now being connected to the final electronics and cooling lines for the pre-commissioning. The Detector Control System architecture has been developed under DT responsibility.
ALICE ITS Outer Layer 6, assembly of 24 staves 1.5m in length
The large composite structure of the ITS that supports in position the staves and the services as well the structure named Cage, that provides support and positioning inside the TPC to the ITS, MFT and the beampipe, have been produced under DT responsibility. A dry insertion of all the final mechanical parts of the ITS and MFT has been performed by the DT team in the devoted area in the clean room where an entire setup, simulating the TPC bore and the insertion infrastructure, is in place. A design challenge for the new ITS installation scheme, was given by the requirement of rapid access to the ITS barrels during a yearly LHC winter technical stop, lasting 3-4 months. This requirement excludes the possibility of displacing or dismounting the surrounding detectors, as was the case up to now, where the extraction and insertion back of the tracker would have required about 7 months. The DT-EO engineering team has developed a new installation strategy that allows for the translation of the ITS detector in halves by approximately 3m along the beam- pipe. During the translation, the two ITS halves progressively move apart in order to gain some clearance to the beampipe, and such to account for the different diameters of the pipes’ central section. This new strategy is based on a completely new design for the global mechanics of the
13
Central Detectors, that includes not only the ITS, but also the MFT, the Fast Interaction Trigger (FIT) detector and a new external structure that provides the rails to guide the translation. DT-EO team had the responsibility of the final design as well of the production follow up. Production of all parts in Carbon Fiber Reinforced Polymer (CFRP) has been finalized in 2018 and they are now being validated through a dry insertion tests with all Central Detectors mechanics.
1. ALICE Central detectors mechanics: allows for fast extraction of ALICE Central Detectors Half Barrels
2. ALICE ITS Outer Half Barrel (Layer 6)
3. ALICE ITS Inner Half Barrel Half (Layer 2)
Muon Forward Tracker The sensor and readout chips for the new ITS will also be employed in the muon forward tracker (MFT), which tracks muons close to the beam pipe. In the DT Micro-pattern Technology workshop the full production of the aluminium FPC for the five disks of the MFT has been completed. MFT has also adopted the same mechanical substrate design developed for the ITS and based on high thermal carbon lay-up with embedded polyimide tubes. Technology transfer and a first substrate prototype has been provided by the DT team to the MFT Group.
ALICE MFT disk mechanical substrate
14
Time Projection Chamber
A major upgrade of the ALICE time projection chamber (TPC) is key for the ALICE upgrade programme. The current TPC read-out, based on multi-wire proportional-chamber technology, will not be able to cope with increased interaction rates, so it will be replaced with multi-stage gas electron multiplier (GEM) chambers.
ALICE TPC GEM foils and Chamber
The production of large-size GEM foils at the DT Micro-pattern Technologies workshop has been completed with the DT Gas-Detector-Development (GDD) Lab support for the GEM foil test. The final assembled TPC Chambers have relied on the support of GIF++ Lab for the full characterization and are now ready to be installed in the TPC.
New Central Detectors and overall LS2 work plan
For ALICE the LS2 activities started at a fast pace. In December 2018, after the massive red door opening, the different ALICE groups began disconnecting their detectors allowing for the removal of the Mini-frame, a large “plug” that brings all the services inside the L3 Magnet.
ALICE Mini-frame with feed through services removal
15
With the Mini-frame on surface, a complete rework has started with the installation of the Delphi-frame in front of the ALICE experiment. This marked the start of the de-installation sequence for the central detectors. One after the other FIT, TO, V0, Tracking detectors and finally the central section of the beampipe, came out from the TPC bore extracted from the Delphi-frame.
ALICE TPC inside the Delphi-frame moving to surface for upgrade
Finally was the turn of the giant TPC that gently moved in the Delphi-frame and found its route to the surface, hoisting from one crane to the other. The TPC entered a large clean room where it will undergo a complete metamorphosis which should take around 11 months. At present the removal process is continuing in the cavern. Most of the calorimeters have been removed for refurbishment. The P2 team, based on DT technicians and engineers, is the central core for coordinating and executing all these activities in the ALICE experimental cavern.
2.2. ATLAS Upgrade
Phase I: Micromegas for the New Small Wheel
Hans Danielsson, Rui De Oliveira, Francisco Perez Gomez
EP-DT-EF has been involved in the detector development and several activities related to the start-up of the mass production for the New Small Wheels (NSW) for ATLAS. Group members have been in the site certifications for the LM2 modules (one out four module types). The assembly tooling and assembly procedures were developed in DT-CO and DT-EF for the LM2 chambers. The technology was transferred to the two assembly sites at JINR (Dubna) and Thessaloniki in the past years. The Micro-Pattern Technologies unit has not only been involved in the development of the Micromegas technology for the New Small in ATLAS, but also in the procedure for cleaning and high-voltage validation. The quality control, cleaning and high-voltage validation are crucial steps in the Micromegas production. Some cleaning and high-voltage testing issues related to the cleaning and qualification of the completed detectors, were discovered on the different assembly sites in 2017. Therefore, in order to solve these problems, the ATLAS management decided to form a taskforce, with members from both the assembly sites and EP-DT, in order to understand the problem and propose solutions. The work was completed in the fall of 2018.
16
Left: Dry cleaning of the drift mesh at Saclay following the new cleaning procedure implemented in 2018. Right: Cleaning and polishing of a Micromegas drift panel during a visit by EP-DT team to the assembly site at JINR.
Phase II: Inner Tracker Pixel Upgrade
Diego Alvarez Feito and Andrea Catinaccio
In 2018, the DT group continued playing an important role in the ATLAS Phase II Pixel Upgrade. Once again the DT efforts focused on the Outer Barrel (OB), working closely with EP-ADE on the design, prototyping and coordination aspects of the project. Following the recommendation of the second ITK Pixel Layout Task Force, the use of Quad modules in the inclined sections of the Outer Barrel was adopted as a baseline. However, whilst the new layout should offer important benefits during the construction, it represents a substantial departure from the one presented in the TDR and introduces additional complexity in the mechanical design. In order to accommodate these changes, the DT group led a major re-design of the local supports, the global structures, the cooling manifolds and the overall integration scheme. The revised mechanical concept, which has been developed in close collaboration with the Université de Genève, makes extensive use of the technical solutions validated for the previous version of the layout. The design of the OB local supports relies on two main elements, namely: (i) the module cells and (ii) the functional local supports. The pixel modules are bonded to the cells, which are comprised of a pyrolytic graphite heat spreader and an aluminium-graphite cooling block featuring machined locators for positioning purposes (see the Fig. below). Each individual cell is connected to a thin-walled, titanium cooling line containing boiling CO2 through a soldered base block made in aluminium-graphite. The cooling lines and base blocks are glued to carbon composite structures to produce the so-called functional local supports. Two different types of functional local supports are employed: beam-like structures coupled with longitudinal cooling pipes, also known as “longerons”, are used to support the modules in the central flat section; conical “half-rings” featuring semi-annular cooling pipes are employed in the inclined regions.
CAD view of a module cell used in the Outer Barrel. The same cell design is used in both the flat and inclined sections
to maximize the advantages of the all-quad module layout.
17
The cooling blocks of the cells and the base blocks of the functional local supports are joined together via M1 screws, relaying on a pin-hole system to control their relative positioning. A thermal interface material is placed between the two blocks to reduce the thermal impedance. This solution gives the OB concept a distinctive advantage in terms of re-workability, as a single module cell can be easily replaced or temporarily removed for repair during the construction phase.
Left: CAD view of a functional longeron, including CFRP truss structure, the cooling pipes and the base blocks. Right: Schematic representation of a functional inclined half-ring, featuring a semi-annular cooling pipe with the soldered
base blocks, the CFRP shell structure and the gussets with glued inserts.
The inclined half-rings of a given Outer Barrel layer are mounted on the inner side of a carbon fibre semi-cylindrical shell through lightweight gussets. The electrical and cooling services for the inclined rings are routed atop the so-called “half layer shells”, which feature machined openings to make the necessary electrical and fluidic connections. For a given detector side (i.e. A or C), CFRP interlinks connect the half layer shells for the three OB layers at two positions along the beam axis. The longerons of each layer are fixed at both ends to the corresponding half layer shells. Four additional semi-cylindrical shell structures (referred to as “service support shells”) are used during the assembly process to support and ease the handling of the OB Type-1 service extensions, which are routed between the Endcaps and the Pixel Support Tube (PST) to reach the Pixel Patch Panel.
CAD view of an Outer Barrel Half featuring three half layers, each comprising two inclined units connected
mechanically by the corresponding longerons. The image also shows two service support shells designed to ease the routing of the Type-1 services towards PP1.
Extensive numerical simulations have been carried out within the group to drive the design and optimization of the various OB components described above. Thermal, thermo-elastic, modal and thermo-fluidic analyses have been performed to assess the feasibility of the revised concept and ensure that the different components and the final assembly will meet the detector requirements. Details are given in the following figure.
18
Top left: Temperature distribution in the silicon sensor predicted by the FEA model of quad cell assuming a non-homogenous power dissipation in the front-end chips, a CO2 saturation temperature of -35 °C, a mass flow of 5 g/s
and a vapour quality of 20%. Top right: Thermo-elastic deformations obtained with an FEA model of a longeron subject to gravitation loads when cooled down from 22°C to -35°C. Bottom: Total deformation obtained with an FEA
model of the OB in its final configuration inside the inner bore of the PST.
In parallel to the design and analysis work, the prototyping activities for the Pixel Outer Barrel continued throughout the year. This effort included the development and optimization of the production methods and associated tooling for the various carbon composite structures used in the functional longerons and inclined half-rings, resulting in the manufacturing of initial prototypes at the DT Composites Lab.
Left: CAD view of the tooling developed for the production of the CFRP structures used in the longeron and the
inclined half-rings (right).
19
The group also remained committed to the completion of the OB Demonstrator Programme, contributing to the assembly and testing of various thermal and electrical prototypes and supporting the development and construction of the required test infrastructure in building 154 and in SR1. In this framework, a 1.6-metre functional longeron populated with forty-four cells loaded with thin-film silicon heaters featuring embedded RTD sensors was built and it is currently under testing to assess the thermal performance and manufacturing variability of the design.
Images of the Long Thermal Prototype of the Outer Barrel built to assess the thermal and production performance of
the demonstrator design. The prototype, which is installed in a purpose-built test setup featuring a 2.4m-long vacuum vessel and a custom-made thermal readout, is located in Building 154.
In addition, the first twenty pixel hybrid modules using FE-I4 front-end chips were loaded on the final demonstrator, becoming the first local support with multiple serial powering chains built for system testing by the ATLAS Pixel community. Also, the Detector Interface section is actively involved in the development of the FELIX readout employed in these tests.
Images of the first half of the electrical cooling line of the final Outer Barrel Demonstrator. The prototype, which has
been loaded with seven quad and thirteen dual modules featuring FE-I4 chips and is connected to a CO2 cooling plant, features three separate serial powering chains to be used for system tests.
20
Finally, the DT group continued playing a leading role in the ongoing ATLAS ITk material qualification campaign. This activity involves the coordination of a common effort to study the effect of gamma irradiation on the thermal and mechanical performance of various adhesives, potting compounds and thermal interface materials (TIMs). In this respect, an improved test setup to measure thermal conductivity of TIMs before and after irradiation has been built and commissioned by the group.
Left: Test setup built in the DT group to measure the thermal conductivity of adhesives and thermal interface materials before and after irradiation. Right: Testing of a single-lap bonded joint used to assess the effects of
gamma irradiation on the mechanical performance of different adhesives.
2.3. CMS Upgrade
CMS Tracker Upgrade
Antti Onnela
For the CMS Tracker’s Phase 2 upgrade, scheduled for installation during LHC LS3 in 2025, the DT
group collaborates with the CMS team in the development and construction of the Outer Tracker
as well as the Tracker’s common items and integration.
DT has a central role in the development of the 2S (strip + strip sensors) and PS (pixel + strip sensors) modules. The focus of DT’s contribution is on the development of the assembly techniques and qualification process for these novel module types, as well as preparing and maintaining 3D models and 2D drawings of the modules’ mechanical assemblies. Those reference models and drawings are used throughout the Tracker upgrade project. Further 2S module prototypes were built, to test and refine the module design details and assembly procedures, as well as to evaluate the mechanical functionality of the module components. High-performance composite components were produced in DT for the module electronics hybrids, designed by the EP-ESE group. For the tilted detector concept, developed by the DT and CERN CMS groups, the key objective in 2018 was the manufacture of the needed high-precision tooling and components for the first tilted “Ring”, a key structure of this novel detector concept. The completion of the first full Ring prototype is due by summer 2019. Detail designs for the tilted detector assembly procedures and tooling were developed at DT, in collaboration with collaborating institutes. A substantial effort was put in studying the integration of all needed services (cooling, electrical, optical), including all details of access and connections. Multiple calculations were made to assess the mechanical performance of the tilted detector structure and compare to the requirements set on the detector geometry.
21
The CMS Outer Tracker 2S module during one of the assembly steps (left) and under one of the final metrology measurement (right).
Mockup of a part of the tilted detector, used for studying the detector assembly procedures and integration of all needed services (left). Finite element calculations were used to study the behaviour of the tilted detector geometry
under gravitational and thermal loading (right).
Tracker integration models are prepared and maintained in EP-DT.
22
Engineers and designers of the DT group prepare and maintain Outer Tracker project’s reference 3D models used for integration and services studies (cooling pipework and cabling). An essential task in 2018 was to adapt the Tracker’s geometry to match with the newly proposed Barrel Timing Layer detector that will share the same global support structure and thermal enclosure with the Tracker.
CMS High Granularity Calorimeter
Eva Sicking
The CMS experiment will upgrade its calorimeter endcaps for the HL-LHC phase with a highly granular sandwich calorimeter, the CMS Calorimeter Endcap (CE), also often referred to as CMS High Granularity Calorimeter (HGCAL). Once installed, it will have an active area of 600 m2 of silicon sensors with 6 million individual readout cells and 500 m2 of scintillator tiles each coupled to a SiPM with approximately half a million individual readout cells. In 2018, group members of EP-DT and EP-LCD (Linear Collider Detector) focused on the development and the improvement of silicon-sensor testing systems and the corresponding characterization of HGCAL silicon sensors. Furthermore, the team participated in several beam tests of HGCAL prototypes: A probe station equipped with a customized probe- and switch-card system was used for the electrical characterization of various HGCAL silicon sensors made from 6-inch and 8-inch wafers with hundreds of pad sensors. Beside the per-cell leakage current, the team measured in 2018 for the first time the per-cell capacitance. The figure below shows experimental results for cells on a 6-inch wafer mostly of 1.1cm2 size. The capacitance results, which include both the bulk capacitance and the inter-pad capacitance, reveal four regions of different inter-pad distance (20µm, 40µm, 60µm, and 80µm) present in this particular sensor design.
Per-cell leakage current at 1000V (left) and per-cell capacitance at full depletion (right) of one example HGCAL 6-inch
135-cell sensor.
As the CMS forward calorimeter region will be exposed to high radiation levels at the HL-LHC, irradiation tests are performed for all sub-components of HGCAL. In 2018, silicon sensors were irradiated in the Ljubljana irradiation facility using a range of neutron fluences, corresponding to what is expected for the HGCAL polar angle coverage. The characterization of the irradiated sensors is ongoing. The silicon test systems were adapted to cope with the significantly higher leakage current expected for irradiated silicon sensors. Furthermore, a system to characterize the silicon-sensor properties in terms of noise and charge collection efficiency after irradiation using full readout ASICs was developed and used for the first time in 2018 on non-irradiated sensors. The measurement concept of the charge collection efficiency was developed in close collaboration with
23
the Solid State Detector (SSD) team of the EP-DT-DD group. A probe station to test irradiated sensors at low temperature was purchased and is expected at CERN for 2019. In 2018, the refurbishment of the former cleanroom for the assembly of detector modules for the CMS silicon strip detector (186-1-G21/G23) was completed. The infrastructure for characterizing HGCAL silicon sensors moved to this room in summer 2018. The room was equipped and the services were set up in consultation with the DSF cleanroom team of the EP-DT-DD group. Several HGCAL beam tests were carried out in 2018 at CERN and at DESY Hamburg. The tested prototypes comprised up to 94 silicon-based modules of 6-inch size and 128 readout cells, arranged in various configurations optimized for different particle beams and energies. The electromagnetic section (CE-E) with up to 28 layers used single modules per layer and lead absorber plates (total of 26X0 or 1.2λI). The hadronic, silicon-based section (CE-H-Si) with up to twelve layers used up to seven modules per layer and iron absorber plates (total of 4.5λI). The CALICE Analogue-HCAL prototype with up to 39 layers equipped with in total 22000 scintillator tiles coupled to SiPMs and steel absorber plates (total of 4λI) acted as backing calorimeter for the silicon-based detector part. The figure below shows an example event display of a hadronic shower recorded in one of the tested configurations. Test beam data from minimum ionizing particles, electromagnetic showers and hadronic showers with energies from 20 to 300 GeV are currently being analysed to investigate the energy, position and timing resolution of the combined prototypes.
Event display of a 250 GeV pion event recorded with a combined setup of HGCAL (CE-Electromagnetic and CE-
Hadronic-Silicon) and the CALICE AHCAL.
2.4. LHCb Upgrade
The LHCb Upgrade I will be installed during the two year Long LS2. The upgraded detector will be able to read out all sub-detectors at 40MHz and to select physics events of interest by means of a pure software trigger at the bunch crossing rate of the LHC. This capability will allow the experiment to collect data with high efficiency at a luminosity of 2 × 1033 /cm2/s.
VELO Upgrade
Raphael Dumps and Alessandro Mapelli
The VELO upgrade detector will be made of planar silicon sensors with pixels of 55 x 55 μm2, which represents a significant increase in granularity and spatial resolution. The upgraded VELO will reuse parts of the current mechanical infrastructure, in particular the vacuum tank. Other elements have to be redesigned such as the vacuum feedthroughs which consist of complex parts assembled in a very confined space. The feedthroughs will allow the routing of all the services in and out of the secondary vacuum volume.
24
View of a VELO detector half with the modules on the right, the feedthroughs for the cables and services in the
center and the isolation vacuum on the top.
In 2018, DT continued working on the design, fabrication and assembly of all the related mechanical parts. It also provided engineering support for the cooling, mechanics and integration. Moreover, the group is now in charge of the upgrade of the motion control system and it provides technical consultancy for the development of the silicon microchannel cooling plates. The testing of the microchannel plates is being performed in a DT lab with logistical support from the group for the CO2 cooling plant.
Left: Mechanical module mockup with microchannel cooling substrate, silicon tile heaters and hybrid PCBs. Right: an assembled prototype VELO module
DT is supporting the LHCb collaboration in following up the manufacturing of the cooling plates at CEA-Leti. All the technical issues encountered during the microfabrication process are closely followed and addressed by DT in close collaboration with LHCb and CEA-Leti. In particular, in order to recover wrongly-diced cooling plates, a special dicing procedure using the LASER setup of the CERN main workshop was defined. It allowed the VELO team to continue working on the assembly with minimum impact on the production schedule. Upon reception of new cooling plates at CERN, a detailed QA/QC procedure is followed which involves pressure testing, visual inspection as well as a detailed analysis of the bonding interface images obtained by acoustic microscopy. Every cooling plate is also undergoing a detailed metrology with a Keyence 3D microscope. The 3D metrology on the cooling plates is performed before and after the soldering of the metallic connectors in order to assess their planarity throughout the process.
25
Upstream Tracker
Joao Batista
Another tracking systems to be upgraded is the Trigger Tracker (TT) that will be replaced by a high-granularity silicon micro-strip, Upstream Tracker (UT). The UT comprises four detection planes perpendicular to the LHC beam pipe. The detection planes are materialized by placing vertically and on a stereo angle (±5°) staves. These staves, which serve as a support to the silicon sensors, are made of a carbon fiber reinforced polymer (CFRP) composite sandwich. The staves are cooled down with two-phase CO2 fluid at -25°C. The staves are enclosed in a thermal insulated box that also serves as the support to the detector components. This box, as the detector, is intersected by the beam pipe and is physically divided in two halves in order to allow the detector movement with respect to the beam pipe.
Various elements of the UT system and its environment
UT prototype mechanical parts and assembly
Supports for staves
UT box plate- CNC machined aluminium plate UT prototype – C-frame with dummy staves
UT prototype – Pigtail length check
UT CFRP sandwich panel
Pins
26
During 2018, in order to study the mechanical integration of the UT detector, a prototype was built. This prototype served to validate the key mechanical components that are required to align and support the UT detector i.e. i) the mechanical supports for the staves ii) the C-frame that is used to support the entire detector and iii) the carbon reinforced sandwich panel. Prototypes of these mechanical components were manufactured in the DT workshops and composite lab. The integration and the mechanical design of the PEPI (Peripheral Electronics Processing Interface) were revised by modifying the existing mechanical components in order to accommodate the new design of the backplane electronics board. Additionally, the geometry of the flexible pigtails, that connect the PEPI electronics to the UT staves, were defined and verified through digital models and physical prototypes.
Model of the PEPI assembly
During the fall of 2018 a 2-day workshop was organized at CERN in order to review the UT assembly and commissioning. This workshop was an opportunity to discuss interface tasks and to prepare the UT slice test and fully instrumented stave that are scheduled for the Spring of 2019. The cooling of the UT requires a number of studies and tests before the operation. In order to create the desired pressure drop at the expected flow rate, restriction orifices are considered. A series of tests was conducted to define the orifice appropriate size. Further tests have been performed on the UT box prototype in order to study its thermal behaviour and to determine the heat transfer of the beam pipe that traverses the box. These measurements have been performed on a scaled down prototype of the UT box and using a prototype of the beam pipe made of aluminium. In conclusion, during 2018 the main mechanical parts of the UT were designed and its mechanical integration and functionality were verified with prototypes and by performing mechanical tests. These prototypes and test were performed in collaboration with the DT workshops and composite laboratory. Additionally, the cooling section of the DT group played a key role by providing advice on the design, manufacturing and operation of the UT cooling system and the cooling system required for the UT slice test and fully instrumented stave. The production of the UT mechanical parts and remaining cooling components is planned during 2019 which is in line with the LHCb phase I upgrades.
Scintillating Fibre Tracker
Sune Jakobsen
The SciFi tracker is the replacement of the Outer Tracker (based on gas straw tubes) and Inner Tracker (Silicon micro-strips) by a single detector technology and will be installed in LS2. The
27
detector consists of 3 tracking stations with 4 independent planes each (X-U-V-X, stereo angle ±5°) and extends over 6 m in width and 5 m in height and has a total active surface of 340 m2. 2.5 m long blue emitting scintillating plastic fibres of 250 µm diameter are arranged in a staggered close-packed geometry to 6-layer fibre mats. One end of the fibre is fitting with a mirror and the scintillation light exiting at the other end is detected by linear arrays of SiPM detectors (128 channels of 0.25 x 1.6 mm2 size). In 2018 the procurement and quality assurance of the scintillating fibres was finalized. A total of 12000 km of fibres has been validated by the DT team. A campaign to monitor long term aging of fibres has continued and is still ongoing. The DT team has been instrumental in setting up two halls for assembly and testing of the detector. This has included designing and building infrastructure and overseeing the production of a NOVEC baby demo cooling plant by EN-CV. The Detector Interface section of our group has built a vacuum system, which is needed for isolation of the coolant (NOVEC at -40°C) transfer lines and manifolds. Furthermore, the DT gas system team has designed and built a dry gas supply system for use during detector assembly at the surface. The dry gas is critical to prevent condensation and frosting on the SiPM photodetector arrays, which will be kept at a temperature of -40°C. Both the vacuum and dry gas supply system also serve as prototypes for the final cavern installations. The concept and design of final cavern systems has been finalized and production, installation and commissioning have been planned for 2019 by the same teams. To monitor the flow of dry gas in every coldbox containing SiPMs, the Detector Interface section has designed and built a prototype flowmeter readout system, which will be scaled to read out ~500 flowmeters in the final system. A full size prototype C-frame has been build and DT has contributed by producing the vacuum isolated NOVEC lines, dry gas manifolds, piping for dry gas, dry gas flow monitoring, vacuum monitoring, etc. and overseeing the overall assembly by university teams.
Prototype SciFi C-frame
28
A first version of a Detector Control System for has been made with strong participation of DT and is used to control and monitor the prototype and services in one of the assembly halls. A DT group member was acting as deputy project leader for the SciFi tracker until mid-2018, but had to leave the project and group as he had to assume new functions in the EP department management. A new DT member has picked up most activities and is responsible for SciFi services, CERN host facility coordination and the overall detector assembly.
RICH and TORCH
Thierry Gys
Beyond the framework of the ERC TORCH project, activities have been on-going with extensive tests of final MCP prototypes and dedicated multi-channel readout electronics instrumenting a small-scale TORCH module prototype (“mini-TORCH”) and a full-width, half-scale TORCH module prototype (“proto-TORCH”). Mini-TORCH was tested in a 3-week beam test campaign at the PS in June 2018, and proto-TORCH in another 3-week beam test campaign in October/November 2018. Both TORCH prototypes were for the first time instrumented with the final version of readout electronics. MCP ageing tests on prototypes with extended lifetime have been completed. During the year 2018, the LHCb-RICH detectors have been running smoothly until the very last day of LHC Run II. One HPD maintenance campaign was performed in February 2018 in which 28 degraded HPDs from RICH2 were replaced. All re-processed HPDs implementing getter strips continued to show stable behaviour. One SPS beam test campaign in the H8 beam line was carried out in October 2018. The integration of several LHCb sub-detectors in a common DAQ system was successful. The RICH-upgrade test vessel designed and manufactured in DT included the latest versions of basic upgrade units, and two complete photon detector modules. One module was equipped with sixteen 1” multi-anode PMTs and one module with four 2” multi-anode PMTs. In these beam tests, a new RICH data-taking scheme pioneered background reduction through high-speed time selection of Cherenkov photons. In parallel, system tests of MaPMTs with LHCb upgrade readout electronics were pursued in the dedicated DT laboratory infrastructure.
Cherenkov ring from a radiator lens detected with MaPMTs
Muon system
Burkhard Schmidt
The upgraded LHCb detector foresees modifications to the beam plugs under the Hadron Calorimeter (HCAL) and Muon station M2, and additional tungsten shielding in the position of the PMs for the readout of the innermost HCAL cells not used in the LHCb. Simulations studies have
29
shown that the particle flux in the innermost region of station M2 is reduced by 60% through a better absorption of shower particles in the proposed shielding. During 2018 am ECR has been carried out for the beam-plug under the HCAL, which comes closer to the beam-pipe. Furthermore, the designs for the various elements have been refined and the order for the material have been prepared.
Area with 20mm clearance to the beampipe; area with only 10mm clearance
Left: Model of new HCAL beam plug. Right: Details design of new tungsten shielding (in dark red)
Upgrade Preparation and Integration Studies
Mark Hatch and Olivier Jamet
Two new storage facilities have been organized and are now in place. A larger one (25m x 15m), for the temporary buffer storage of parts (some radioactive) removed from the cavern. A smaller one (13m x 6m) for the temporary storage of new cable drums. The cables will be installed during LS2.
One of the new Storage facility at LHC Point 8 (LHCb)
For the dismantling of some existing sub-detectors, and subsequently the installation of new sub-detectors, the members of the LHCb collaboration have been asked to produce procedural and safety documentation. These documents show how they will do the work (procedure document) and what safety measures will be taken to mitigate against identified risks (safety plan). They are a precursor to the start of the work on site to facilitate the IMPACT and VIC processes.
30
Integration studies have been made using CATIA to plan the installation of sub-detectors and related cooling plants. Examples are shown in the following figures. The CO2 cooling plants will be installed in one of the alcoves in an area protected from radiation at a distance of about 80m from the detector. Additional platforms are foreseen, e.g. above the RICH 2 detector, to facilitate the access. Since the first half of the UT detector might be ready for installation only after the beampipe has been installed again, a study had been carried out in 2018 for bringing it in place at a later time, as shown on the bottom figure.
Left: Studies for the installation of the CO2 cooling plants. Right: Studies for a new platform above RICH 2
Studies for the installation of the UT detector
31
3. Collaborations with non-LHC Experiments
3.1. CLOUD Antti Onnela
CLOUD’s main activities in 2018 were the CLOUD13T technical run, the CLOUD13 physics run and preparations for the substantial modifications of the CLOUD area that due to be executed in 2020. The technical run focused on development and commissioning of new measurement instruments. The physics run focused in studying a) aerosol nucleation in marine environment, b) pure biogenic nucleation & growth under realistic environmental conditions and c) anthropogenic nucleation & growth under polluted urban conditions. DT contributed to the experiment by an engineer acting as the CERN CLOUD team leader, CLOUD experiment’s resource coordinator and Safety officer, by a technician providing support to the experiment’s maintenance activities and to visiting scientific teams, and by the DT gas team adapting and maintaining CLOUD’s gas systems. As a new activity DT’s Detector interface section provided support in developing CLOUD’s slow control systems. A new EU-funded Marie Curie programme, CLOUD-MOTION, started in late 2017 and allowed hiring of two doctoral students that started with the CERN CLOUD team in early 2018.
CLOUD13 was the biggest physics run until now, counting the number of measurement instruments. Adapting equipment for the specific needs of each run and integrating the instruments around the aerosol chamber generate
a peak workload on the DT contributions to CLOUD.
Several enhancement projects were executed by the CERN CLOUD team in 2018 in order to enable the CLOUD Facility to meet the goals of the scheduled next runs. These projects concerned in particular the light sources and gas systems, CLOUD’s central DAQ and the slow control systems. A new, high-capacity air extraction system was installed to remove heat from the instruments and to ensure correct operating and work conditions in the CLOUD area. Detail design and planning work was pursued in 2018 in close collaboration with the EN-EA group to prepare CLOUD for the PS East Area renovation due in 2020.
32
With the forthcoming enlargement of the CLOUD beam area in 2020, the platforms surrounding the aerosol chamber will be enlarged (shown in green). Design and planning are developed together with the East Area team to ensure
that the new installations can be done efficiently and matching with the overall schedule of the renovation project.
3.2. NA62 Hans Danielsson
Data taking & results
The data taking in 2018 lasted for 217 days, from April 9 to November 12 (56 days longer than in 2017). Beam intensity was kept stable at 60–70% of nominal, optimized for efficient data taking conditions. The FRC of November 2018 approved the budget for 2019-2020, which will allow NA62 to prepare for data taking after LS2. The plan is to increase the intensity and run at 100% of the nominal intensity from the start of data taking 2021. With a lower background level than that in
2016 and an expectation of about 3 Standard Model K+ → π+ν ν ̄ events, the NA62 collaboration foresees a publication in 2019 surpassing the E787/E949 (BNL) sensitivity, which is the best branching ratio measurement until now. They have demonstrated that the signal-over-background
ratio for K+ → π+ν ν ̄ does not deteriorate significantly when increasing the beam intensity. In addition, efforts are made to improve the random veto and the analysis is focusing on decreasing the background further. The precise evaluation of the total statistics collected in 2018 is under study.
Detector operation & maintenance
Improvements on the radiation shielding were made prior to the 2018 data taking. The electronics racks for the KTAG, CHANTI and GTK cooling stations were equipped with additional concrete blocks to decrease the number of single event upsets (SEUs). In addition, neutron shielding (boron carbide) was added to electronics racks of the KTAG. A reduction factor greater than 10 for high-energy hadrons was achieved and the thermal neutron flux was decreased by a factor greater than 25. The boron carbide shielding alone, decreased the thermal neutron flux by a factor greater than 10. The level of the liquid Krypton in the LKr detector has been stable since the summer of 2017 and there is no urgent need to top up the liquid Krypton at this point. Nevertheless 400 litres of liquid Krypton were bought in 2017 and they will be added to the Krypton storage dewar later in 2019. A dedicated device has been built to validate the purity of the Krypton by measuring the
33
lifetime of the drift electrons. The first tests with this new device were carried out in the summer of 2018. At present the plan is to transfer the Krypton to the storage dewar during LS2 once the purity of the Krypton has been measured and fully qualified. No major detector upgrades are foreseen during LS2. A schematic of the present experiment is shown in Fig 1. The GigaTracker (GTK) detector operation was successful in 2018. Based on the experience on running the GTK, we foresee the need for 6 detector modules per year (3 in the beam + 3 spare). Taking into account some contingency in fabrication and operation, we aim at fabricating 15 new modules to cover 3 years of data taking. Orders for all required parts have been placed.
The major maintenance operation during LS2 concerns the vacuum system. In particular, the cryo-pumps of the vacuum system will undergo a thorough check and replacement of key components by an outside company. This will allow for efficient running of the vacuum system until LS3.
Layout of the NA62 experiment KTAG: differential Cherenkov counter; GTK: Si pixel beam tracker; CHANTI: ring stations of scintillator slabs; LAV:
lead glass ring calorimeters; STRAW: straw magnetic spectrometer; RICH: ring imaging Cherenkov counter; MUV0: off- acceptance plane of scintillator pads; CHOD: planes of scintillator pads and slabs; IRC: inner ring shashlik
calorimeter; LKr: electromagnetic calorimeter filled with liquid Krypton; MUV1,2: hadron calorimeter; MUV3: plane of scintillator pads for muon veto; HASC: near beam lead– scintillator calorimeter; SAC: small angle calorimeter.
Gigatracker module preparation
Alessandro Mapelli
In spring 2018, three GTK stations were prepared and installed for the last NA62 Physics Run before the LS2 shutdown. These new stations included modules fabricated with the latest batch of cooling plates with a thickness of 210 µm which were delivered by CEA-Leti in December 2017. Data was taken as soon as the beam was available. Early June however, one tenth of the detector pixels in one of the stations (GTK_3) could no longer be operated. The detector was promptly replaced with the spare detector having the lowest amount of material in the beam acceptance. Unfortunately, immediately after being exposed to the beam the new detector exhibited an unacceptable and increasing number of noisy pixels and had to be replaced. With the exception of these two incidences, the run of the GTK continued smoothly and uninterrupted until the end of the experiment's beam time. As agreed in the WP between NA62 and EP-DT, the production of 6 new GTK stations was pursued throughout 2018. The assembly procedure was updated and is available online (EDMS 1837669). A database with all the GTK modules properties is being updated as the detectors are being
34
assembled and commissioned. All the stations produced in 2018 have been made using thin cooling plates from the latest delivery of December 2017. The GTK has successfully contributed to the running of NA62 in 2018 with approximately 60% more data taken than in 2017. At the start of LS2, the GTKs have been dismounted from the experiment and they are stored in the experimental area. A Procurement Order was sent to CEA-Leti for a new set of cooling plates to ensure the fabrication of the GTK modules necessary for the NA62 Physics Run after LS2.
3.3. ISOLDE Hans Danielsson
EP-DT-EF gives technical support to ISOLDE since 2017 on a number of projects and several of the experimental set-ups. In particular, work has been carried out on two ERC-funded experiments: beta-drop NMR and MIRACLS, with the ISOLDE decay station and solid state experiments. Numerous pieces have been produced for these experiments and technical assistance was given on the structure for the fourth cryo-module for HIE-ISOLDE. The activities at ISOLDE for 2018 involved mechanical support and consultations for projects such as the reconfiguration of the GLM/GHM area in cooperation with the EP safety team.
Panoramic view of the low energy beam lines in the ISOLDE hall
35
4. Projects under Study
4.1. Linear Collider Detector Project Eva Sicking
The Linear Collider Detector (LCD) project focusses on detector R&D for future e+e- collider projects at the energy frontier. In 2018, members of the EP-DT and EP-LCD groups worked together on ultra-low mass vertex and tracker detectors for the Compact Linear Collider (CLIC) as well as on highly granular calorimeters, as discussed in more detail in the following. In 2019/2020, the Strategy of the European Particle Physics will be updated. Members of the EP-DT and EP-LCD groups summarized in 2018 for this occasion recent R&D results of the CLIC detector, the accelerator and the CLIC physics potential as well as the status of the project. The results were published in several CERN Yellow Reports and 10-page summary submissions to the strategy process.
R&D for highly granular calorimeters
Besides the CMS HGCAL activities discussed in Section 2.3.2, members of the EP-DT and EP-LCD groups work together with the CALICE (Calorimetry for Linear Collider Experiments) and FCAL (Forward Calorimetry) collaborations on highly granular calorimeters for future e+e- colliders. In 2018, the work mostly focused on preparations for FCAL beam tests scheduled for 2019 of an ultra-compact sampling calorimeter prototype. The team commissioned a system to test LumiCal silicon sensors prior to module assembly. The test system is based on the probe- and switch-card test system initially developed in the context of CMS HGCAL described in Section 2.3.2. The team produced and installed a probe card and mechanical infrastructure for the tests of LumiCal sensors into a probe station as shown in the figure below. First measurements of the leakage current and the capacitance of the sensor cells as a function of the bias voltage were recorded.
Furthermore, EP-DT group members were responsible for producing ultra-thin carbon fibre envelopes foreseen to host the silicon sensors. The envelopes were produced in the DT Composite Laboratory and consist of glued stacks of six 100 µm thick woven carbon fibre plies. The thickness goal of below 750 µm was comfortably met with most of the envelopes not exceeding 600 µm while providing the requested mechanical stability.
A LumiCal silicon sensor made from a 6-inch wafer tested in a probe station using a probe- and switch-card
system (left). Per-cell leakage current of the LumiCal silicon sensor at 500V (right). One cell in the right
column does not have a good contact such that its current is collected by its neighbour cells.
36
4.2. Neutrino Platform
Engineering Studies for the Neutrino Experiments
Andrea Catinaccio and Jaakko Esala
In 2018, the EO section continued to contribute to the design and calculation of the warm structure of the Long Baseline Neutrino Facility (LBNF) liquid argon cryostats. Following the successful Final Design Review in August 2017, work continued on studying the remaining details of the design, as well as verifying the calculations with full scale tests.
The LBNF cryostat warm structure (exploded view)
A test campaign of full scale connections of the cryostat was executed by the Institute of Sustainability and Innovation in Structural Engineering (ISISE) at University of Coimbra. In total, seven specimens were tested with the laboratory’s impressive 600 ton hydraulic jack. In addition, the material of the steel beams and bolts was characterized. The EO section collaborated with University of Coimbra on the testing protocol and correlated the results with analytical calculations and detailed finite element models.
37
Left: C2 test specimen being set up at University of Coimbra. Right: Correlation of the finite element results with the test results. The connection exceeded the analytical Eurocode 3 moment capacity by 35% before failure of the first
bolt row.
All the connections reached and exceeded their calculated load capacity. The finite element models agreed well with the test results and were thus verified. The only exception was the connection type 6 (C6), which is a slip resistant lap joint used on the horizontal belts on the long wall of the cryostat. The friction coefficient in the test specimen was found to be lower than specified and therefore, based on the results of the tests, the horizontal belts were redesigned to be more robust and not dependent on surface friction.
Left: Slip resistant lap joint (C6) in the test Right: View of the instrumentation on the lap joint
set-up after testing
In addition to the test campaign, extensive studies and numerical simulations have been carried out on the remaining details of the design, including: detailed study of the M48 10.9 bolts (a test of a preloaded bolted assembly is foreseen for 2019), force reactions on the cavern floor with different materials, effect of manufacturing tolerances on the strength of the joints and erection of the cryostat, behaviour of the cryostat during vacuum testing of the insulation cavity of the membrane, fixation of the warm membrane to the steel frames with clamps, among others. Work has begun on implementing the information gained from the tests of the individual connections into an updated global cryostat model, where the precise compliances of the connections are accounted. The increased accuracy in the modeling of the global cryostat behaviour can in turn be utilized to study areas of interest in more detail through sub-modeling techniques.
DAQ, Control and Safety Systems
Giovanna Lehmann Miotto, Xavier Pons, Roland Sipos
The year 2018 has been an intense and successful year for the collaboration between the Neutrino Platform and the DT-DI section, which has been heavily involved with:
the installation, commissioning and data taking of the NP04 experiment;
the development and running of the control system for the NP02 cold-box and the
preparation for installation of the NP02 control system;
the layout of the conceptual design for the DUNE DAQ system.
38
NP04 DAQ The installation of the NP04 DAQ system was completed in 2018, with the extension of the local storage space (disk arrays – 700 TB usable storage), the connection to the detector electronics via fiber optics, the installation and commissioning of the trigger inputs (beam instrumentation, photon detectors, cosmic ray tagger) and the integration of additional servers. Besides the installation and connection of the DAQ hardware, in 2018 DT-DI focused on improving the run control system and completing the FELIX based readout. The run control system was extended with full partitioning support, as well as improved operational monitoring and automation features. The integration of the access control ensured proper authentication and authorization of the users and operators of the DAQ system. The introduction of a new the process management mechanism (based on Supervisor) increased robustness and recovery features of the data taking components.
a) Artistic view of the NP04 data flow; b) Zoomed in data flow sketch for a single Anode Plane Assembly (APA)
readout though a FELIX based system.
The FELIX readout system was put into production and exceeded expectations on multiple fronts. The implementation turned out to be flexible and versatile also for infrequent topologies and configurations. In order to meet the throughput requirements, modest modifications of the FELIX firmware were required. On the other hand, important effort had to be put on the software in order to be capable of dealing with these massive amounts of data, both on the FELIX servers side and on the data receiver applications (so called Board Readers), in charge of performing trigger matching, data reformatting and compression, as well as data forwarding to the event builder. Continuous trigger rates of nearly 50 Hz were reached during stress testing for the FELIX readout, to be compared to the required design trigger rate of 25 Hz (only during SPS extraction, i.e. ~1/4 of the time). This performance could not have been achieved if the mandatory task of compressing data had to be carried out in software. DT-DI, in collaboration with Intel and the CERN OpenLab, evaluated and later successfully introduced into NP04 the Intel QuickAssist Technology for hardware accelerated data compression.
NP04 Detector Control System In 2018, after the commissioning tests of the NP04 Anode Plane Assemblies (APA) in the ‘cold-box’ setup, the detectors were finally installed inside the NP04 cryostat. The DT-DI section took care of the installation of all the services needed for the detector operation: LV, HV, DAQ, instrumentation readout, and connected them to the Detector Control System (DCS) racks. The DCS, hardware and software, was successfully and timely commissioned and started being operated 24/7 from summer onwards, during the cool down of the cryostat as well as the subsequent commissioning and data taking of the experiment.
39
ProtoDUNE Single Phase DCS main display. On the right, a plot showing the automatic recovery of a High Voltage discharge 'streamer' inside the cryostat.
A particularly critical element for the control system is the very high voltage power supply used to generate a drift-field of 500V/cm inside the cryostat. DT-DI developed a high-performance control and monitoring system, based on the same technology used for the safety systems of the experimental magnets at the LHC. In addition to ensuring the safe operation of this device and of the overall experiment, the control system implements automated procedures, allowing to quickly recover from any discharges or overcurrent situations inside the cryostat, the so-called ‘streamers’, as shown in the figure above.
NP02 In 2018 the NP02 collaboration established that it was important to check each detector module in a cold-box before installation into the cryostat, similarly to what had been done in NP04. The DT-DI section contributed to the development of the control and monitoring systems and provided electromechanical support. In addition, towards the end of the year the installation of the final control system hardware could start at EHN1.
The NP02 cold-box setup (left); a simple monitoring panel for temperature sensors and level meters (right)
DUNE In 2018 the Interim Design Report was completed for DUNE. The initial ideas on DAQ, combined with the experience gained on the NP04 data taking, evolved into a conceptual design for the DAQ which was reviewed by a panel of experts at CERN in December. The DT-DI section is playing a major role in the design phase of the DAQ, in particular since the FELIX system, evaluated for the first time on a continuous readout system at NP04, has been chosen as the baseline technology for DUNE.
40
In particular, starting in autumn, DT-DI started working closely with colleagues from the DUNE DAQ consortium, in order to demonstrate the ability to select data online based on the activity in the TPC instead of using an external hardware trigger system. This can be done if hit-finding is performed live on all collection wires of the APAs and data are selected, e.g. based on specific hits patterns. Besides providing support for the integration of hit finding algorithms into the NP04 software, DT-DI started a project to re-order and pre-format data in the FELIX firmware in order to optimize them for hit finding performance. In the area of controls, there is an interest in exploring the use of WINCC OA and the JCOP/UNICOS frameworks for the DUNE control system. The successful implementation and operation of the WA105, NP02/NP04 cold-boxes and NP04 control systems have provided a convincing demonstration of the power and flexibility of these toolkits.
4.3. Search for Hidden Particles: SHiP Piet Wertelaers
The Group is contributing in the design of the Spectrometer region of the so-called Hidden Sector part of the SHiP Experiment, currently applying for approval. A mechanical concept for the Straw Tracker has been developed and is currently being improved. A special section of vacuum tank – logging 4 Tracker stations – is dedicated to the Spectrometer region, and the design of that vessel rests entirely in the Group. We are also involved in the Spectrometer Magnet, the yoke of which interferes intensely with the vacuum tank. The baseline variant for that magnet is with "warm" windings, and our expertise herein is also called upon. Moreover, we provide punctual support and consultancy in other subsystems and in matters of technical coordination.
Overview of the SHiP experiment (left), with an exploded view of the magnet and the vacuum tank in the spectrometer region (right)
41
5. R&D on Experimental Technologies
5.1. Radiation Tolerant Silicon Detectors Michael Moll
The Solid State Detector (SSD) lab of the EP-DT group participated in the framework of the RD50 collaboration and the CMS pixel upgrade projects in R&D activities related to silicon sensor developments and radiation damage studies for the HL-LHC and beyond. In 2018 RD50 submitted a 5 years work plan and prolongation request to the LHCC, which was very positively received and approved by the CERN Research Board. EP-DT provided one of the two co-spokespersons, administrative support, the budget holder and the co-ordination of several RD50 projects and participated actively in the ambitious R&D program. The RD50 working fields being subject to the most intensive studies were: Sensors with intrinsic gain for radiation tolerant fast timing (mainly LGADs – Low Gain Avalanche Detectors), characterization of defects responsible for sensor degradation after irradiation, simulation of irradiated device performance, HV-CMOS sensors, small area 3D sensors and the characterization of materials and devices after extreme radiation fluences up to several 1017 particles/cm2. Together with all LHC experiments, two dedicated workshops were organized reviewing the radiation damage effects observed in the operating LHC experiments and benchmarking them against RD50 damage models. While the overall agreement is very good, specific areas like the pixel layers closest to the interaction point showed discrepancies against the modelling and require further work as to the reason of this observation. RD50 continued to give strong support to the CMS Endcap Timing Layer and the ATLAT High Granularity Timing Detector experiments in bringing the LGAD technology to the readiness level required for the respective TDRs. Of highest interest are the increase of the fill factor, the radiation hardness and the long-term stability after high levels of irradiation. The CERN RD50 team in EP-DT (SSD team) was involved in several of these research activities, including the characterization of CMOS sensors, the development of a new laser based device characterization technique (see section 7.2.1.) and the topics discussed in the following.
Acceptor removal The in-depth study on the acceptor removal effect was continued. This effect is responsible for the loss of gain in LGAD sensors for timing and the radiation induced increase in charge collection
efficiency in the bulk of CMOS sensors. Dedicated test sensors with 50 m thick epitaxial p-type
silicon layers of different resistivity (10 to 1000 cm) were produced and irradiated. It was found that after proton or neutron irradiation above some 1015 particles/cm2 the detectors which initially differed by up to two orders of magnitude in the doping concentration showed only very little difference in their characteristics (see next Fig., left). From the microscopic point of view Thermally Stimulated Current (TSC) technique was used to detect and probe the origin of the radiation-induced defects with a special attention to the defects which impact the space charge. The BiOi defect, which contains a Boron atom that is no longer acting as a shallow acceptor, was identified as the main microscopic reason for the acceptor removal. A major outcome of a long term annealing at 60°C was the finding that the deactivated Boron cannot be re-activated by such moderate temperature annealing procedures. An example of TSC measurements on irradiated
samples of 250 cm is given in the following figure (right).
Nitrostrip
The influence of nitrogen on the radiation hardness of silicon sensor is under investigation within RD50. Microstrip sensors and pad diodes were realized using nitrogen rich float zone silicon. Identical structures were produced also on magnetic Czochralski, standard and oxygen rich float zone silicon to provide a comparison. In 2018 an extensive measurement campaign was conducted demonstrating that the introduction of Nitrogen in the order of 2×1015 cm-3 was not significantly changing the radiation response of the sensors.
42
Left: Effective doping concentration versus fluence for several p-type epitaxial silicon sensors with different
doping concentration (10 to 1000 cm) as extracted from CV and IV measurements. Right: Thermally Stimulated Current (TSC) measurements revealing defect levels produced after proton and neutron irradiation. The BiOi defect is detected and identified as the microscopic origin of the acceptor removal effect.
LGADs for precision timing
Low Gain Avalanche Detector (LGAD) is the baseline sensing technology of the recently proposed Minimum Ionizing Particle (MIP) end-cap timing detectors (MTD) at the Atlas and CMS experiments. The current MTD sensor is designed as a multi-pad matrix detector delivering a poor position resolution –due to the relatively large pad area, around 1 mm2; and a good timing resolution, around 20-30 ps. However, the timing resolution of LGAD sensors is severely degraded if the particle hits the inter-pad region since the signal amplification is missing in this region (so-called LGAD fill-factor problem). To overcome this problem and increase the spatial resolution, a p-in-p LGAD (iLGAD) was introduced (see next Fig., left). Contrary to the conventional LGAD, the iLGAD has a non-segmented deep p-well (the multiplication layer). Therefore, iLGADs present a constant gain value over all the sensitive region of the device without gain drops between the signal collecting electrodes; in other words, iLGADs have a 100% fill-factor by design. In 2018 the first iLGAD prototypes were tested in test beams and demonstrated a homogeneity in the amplification over all the sensitive region of the device without gain drops between the signal collecting electrodes (see next Fig., right).
Left: Layout of LGAD (top) and iLGAD (bottom) strip sensors. Right: Charge distribution measured during the test beam for one LGAD strip detector (top) and one iLGAD strip detector (bottom). The LGAD fill-factor
problem is easily spotted and on the contrary, it is not present in the iLGAD structure.
43
APDs for precision timing Another detector structure dedicated to MIP timing applications is the deep diffused avalanche photodiode (APD). The APDs studied within the SSD team are produced by RMD and have an active area of 8x8mm2 and a gain of about 500 at 1800 V. A beam test at CERN, profiting from the RD51 beam test infrastructure and support, was performed. The spatial uniformity of response of the detectors and the signal properties relevant for timing were studied. It was shown that a metallization of the surface in a post processing procedure improves the uniformity of the response leading to a homogeneous time resolution of 44 ± 1 ps over the 7.5x7.4 mm2 area considered for the study. Improvements of the readout electronics are under way and will lead to a better time resolution.
5.2. CMOS Pixel R&D Petra Riedler
The activity on R&D for pixels in DT is focusing on developing generic large area pixel modules for future detectors, building on the experience of current projects. A large area chip, MALTA [10], has been developed with the CERN ATLAS Team, the STREAM Marie Curie Innovative Training Network and EP-ESE (see next Figure). This joint development aims at radiation hard (1015 neq/cm2) and fast (25ns) CMOS sensors as needed for pp-collisions at HL-LHC. The sensors were designed in a 0.18 um CMOS process provided by TowerJazz. The wafers contain a set of chips in each reticle, of which two are large pixel chips (MALTA, MONOPIX) with 2 x 2 cm2 and 2 x 1 cm2, respectively. Furthermore, there is also a set of small test chips included, one of which is an interconnection chip to allow chip-to-chip data transfer from one MALTA to another MALTA chip. The MALTA chip has pixel sizes of 36.4 x 36.4 µm2 and a small collection electrode of 2-3 µm diameter in each pixel cell. Data is transmitted asynchronously over high-speed bus to the end of the column. The output signals are transmitted by 5 Gbps LVDS drivers. In order to verify the output stage a dedicated test-chip (LAPA) was designed and included in the submission [11]. The chips are produced in a modified process in the foundry, originally explored for the ALICE ITS project to enhance the radiation hardness [12].
MALTA chip (2 cm x 2 cm, left image, and LAPA I/O chip mounted on a testcard and wire bonded, right image.
MALTA chips have been extensively tested in the lab as well as with test beams. Even after high levels of radiation, i.e. 1015 neq cm-2, the MALTA sensor still responds to passing particles. However, inhomogenities in the response across a pixel cell appeared, showing lower efficiencies in the pixel corners. This could be attributed to the internal field configuration at the pixel cell edges and a modification of the processing was worked out together with the foundry to counteract this effect [4]. These modifications were included in a test chip (Mini-MALTA) that was submitted in 2018 (see the following Fig., left). First tests of the Mini-MALTA chips after irradiation indicate that the
44
modificaitons maintain the field region at the pixel edges and thus preserve the high efficiency even after 1015 neq cm-2.
Left: Mini-MALTA chips submitted for processing in 2018 with design and process modifications for improved
radiation hardness. Right: Two MALTA chips with direct wire bonding connection.
The special feature of the MALTA chip which allows to transfer data directly from chip to chip is presently being studied by directly bonding between two MALTA chips (see Fig. above, right). Further interconnection studies between two CMOS chips are pursued using the interconnect chip to connect two chips via copper studs. A first evaluation is being carried out using dedicated pad wafers. First mechanical assemblies will become available in the course of 2019.
5.3. Micro-Pattern Gas Detectors Florian Brunbauer, Eraldo Oliveri, Leszek Ropelewski
The EP-DT Gas Detector Development (GDD) team is focused on research and development on gaseous detectors and the exploration of different technologies and applications. Focused on Micro-Pattern Gaseous Detectors (MPGD) the group plays a major role in the coordination and consolidation of the RD51 collaboration, whose prolongation for five years has been accepted and supported by the LHCC in 2018. A few examples of R&D lines and achievements in 2018 will be described in the following: precise and fast timing, optical readout, additive manufacturing techniques and neutron detection. The latter research line is performed in collaboration with the European Spallation Source (ESS), BrightnESS EU project (ended in 2018).
Prototypes and timing setup at the North Area test beam. Top Left: single channel readout PICOSEC MicroMegas with an active area of 1 cm2. Bottom Left: Multipad PICOSEC MicroMegas with an active area of about 10 cm2 and
19 readout pads. Right: Test beam setup at the North Area (RD51 test beam in H4).
45
Precise and fast timing In order to develop a precise timing, robust, radiation hard, large-scale particle detector with segmented readout the PICOSEC project achieved remarkable progresses. The working principle of the detection concept and measurements are described in NIMA 903 (2018) 317-325. With Minimum Ionising Particles (MIP) a time resolution of 25 ps has been achieved.
During several test beam campaigns in the North Area systematic studies on critical detector aspects have been performed. For example performance tests with/without a resistive layer in the readout or the validation of simulation and modelling using a single channel readout detector with an active area of about 1 cm2 (top left in the above figure). Also signal sharing, large area coverage and the capabilities of scaling up the readout from a small area single channel prototype to a large area multichannel detector (see the photograph on the bottom left) has been investigated systematically. One of the most important performance aspects is the stability of the photocathode. Using a DLC coating as CsI alternative, which is produced by our colleagues of USTC in China (left pictures in the below figure) allowed to achieve a time resolution below 40 ps with efficiencies around 95% using 2.5 nm thick layers (central plot in the figure) on a 3 mm MgF2 radiator. In parallel to the search of novel solutions and in order to qualify our studies, we are equipping our laboratory with a QE characterization setup, ASSET (right picture in the figure), usable in vacuum and gas, in transmission and reflective mode. The setup will moreover allow us to do systematic studies of photocathode aging under ion bombardment.
In the figure below, recent results on a multipad PICOSEC MicroMegas used also during the test beam campaigns are shown. On the left preliminary results from our AUTH colleagues on the prototype built and tested at CERN are shown. Time resolutions of about 30 ps are succesfully recovered by combining the signal detected by the involevd pads (three in the studied case, with about 80 ps single pad time response in the case of shared siganl). In addition to the proper understanding of combining signals, the collected data have been extremely helpful on identifying critical aspects as the requiremnets on gaps planarity for larger detectors. Using beam data (left in fgure) and planarity measurements (right in figure) these aspects can be better correlated
Photocathodes. Left: DLC deposition facility (USCT/China) and few DLC photocathode samples with increasing DLC thicknesses. Center: time resolution measurements taken with 2.5 nm DLC measured with 150 GeV/c muon beam. Right: ASSET setup for photocathode characterization in the GDD laboratory .
Multipad PICOSE prototype. Left: Time response of the multipad detector for events with the sharing of the signal between three neighbouring pads. Right: PCB deformation measuremnts by the EN Metrology service to
evaluate the gaps planarity.
46
Ultra-fast optical readout Optical readout of scintillation light emitted in gaseous detectors is a performant readout approach providing high-granularity images without the need for extensive reconstruction algorithms. Previously, this readout approach was limited to integrated imaging due to the low frame rates achieved by imaging sensors. Modern ultra-high-speed CMOS sensors can overcome this limitation and enable image acquisition rates of up to one million frames per second at reduced resolution. Using this technology, we have demonstrated 3D track reconstruction of alpha particle tracks in an optically read out Time Projection Chamber (TPC) from a sequence of images acquired at high speed. In addition to 3D track reconstruction without the need for additional fast photon detectors, ultra-high speed optical readout might enable rapid full-field X-ray fluoroscopy and real-time beam monitoring applications.
Optically read out MicroMegas Gaseous Electron Multipliers (GEMs) are well suited for optical readout due to their geometry while most other Micro-Pattern Gaseous Detector (MPGD) varieties are integrated on opaque substrates inhibiting scintillation light readout. In collaboration with CEA/IRFU, we have demonstrated that a MicroMegas detector integrated on a glass substrate with a transparent indium tin oxide layer used as anode can be optically read out. Using this glass-based MicroMegas detector for X-ray radiography as shown in the left figure below, high spatial resolution was achieved. In addition, the good energy resolution obtained might make this detector applicable for energy-resolved imaging. 3D printed THGEM Additive manufacturing techniques offer unprecedented flexibility and are already widely used for intricate mechanical structures. Employing a novel inkjet-based 3D printing technology combining insulating and electrically conductive materials, we investigated the applicability of this manufacturing approach for detector development.
High-resolution inkjet 3D printing was used to develop a fully printed Thick Gaseous Electron Multiplier (THGEM) as shown in the right figure above. The printed device was operated as a gaseous detector, thus proving the possibility to 3D print functional radiation detectors. While the achievable resolution cannot compete with photolithographic techniques, inkjet 3D printing offers
Ultra-fast optical readout: Frames of alpha particle track recorded in a GEM-based optical TPC at 700 000 frames-per-second, which can be used for 3D track reconstruction.
Left: optically read out X-ray radiograph from MicroMegas detector integrated in a glass substrate with transparent anode. Right: 3D printed THGEM detector combining insulating and conductive inkjet 3D printing.
47
significantly higher geometrical flexibility and shorter prototyping times, potentially enabling result-driven detector development and optimization and evaluation of non-planar structures. High resolution neutron detector for NMX In the framework of the BrightnESS grant, the prototype of a high resolution neutron detector has been developed for the NMX instrument at ESS. The triple GEM detector with Gadolinium neutron converter has an x/y strip readout with 400 µm pitch, an active area of 50 cm x 50 cm and is read out with RD51 VMM3a hybrids and the Scalable Readout System (SRS). A position resolution of better than 300 µm has been obtained with thermal neutrons. A Cadmium mask with 1.0 mm holes, diagonally separated by 1.3 mm, can be clearly resolved.
Integration of the VMM3a ASIC into the Scalable Readout System The VMM3a ASIC, developed for the ATLAS New Small Wheel upgrade, has been integrated into the Scalable Readout System (SRS). The new VMM3a hybrids consist out of two wire-bonded chips with 64 channels each, and will replace the existing APV-25 hybrids. The firmware of the hybrid and the Front End Card (FEC) has been upgraded to support the VMM and to sustain the now achievable high data rates. In cases of highly fluctuating rate, the FEC v6 can now make use of DDR3 memory to buffer the data. Measurements that required hours of data acquisition with the APV-25 are now possible within minutes.
RD51 Five years prolongation of the RD51 collaboration, based on the “R&D Proposal: RD51 Extension Beyond 2018” have been accepted by the LHCC in 2018. A short version of the proposal has been submitted and accepted as input to the European Strategy for Particle Physics. Our EP-DT-DD group is staying strongly involved in the management with putting the spokesperson, the technical co-ordinator and several convenors of the RD51 working groups. We are directly involved in the detector simulations and modelling (Garfield and more) and on development of MPGD electronics. The Scalable Readout System (SRS) is one of the most important examples with large impact in the community. We take responsibility of common facilities at CERN as the GDD laboratory (available for members of the collaborations, MPGD based LHC upgrades as ATLAS NSW , ALICE TPC, BL4S, ESS) and we coordinate common test beam activities at the SPS.
5.4. R&D for CO2 Cooling Paolo Petagna for the DT-FS Cooling Team
On-Detector Cooling R&D
In the frame of the large spectrum programme aimed at providing the designers of new CO2 detector evaporators with reliable quantitative information on the properties of CO2 boiling in mini- and micro-channels, a campaign of high precision measurements of Heat Transfer Coefficient (HTC) and pressure drops have been launched on the new DT state-of-the-art test stand. In
Left: photograph of the a Cadmium mask put into the neutron beam. Right: image of the cadmium mask recorded using a triple GEM detector with a Gadolinium neutron converter.
48
particular, the boiling properties have been carefully investigated in stainless steel mini-pipes with 1 mm and 2 mm inner diameter for the full range of temperatures from -25°C to +15°C, mass fluxes from 100 to 1200 kg·m-2·s-1 and heat fluxes from 10 to 35 kW·m-2. As an example, the HTC values in the full range of temperature and mass flux observed are reported below for four values of the heat flux.
Heat Transfer Coefficient for CO2 boiling in 1 mm and 2 mm ID as a function of the saturation temperature for
different heat fluxes
The values in the above figure are plotted for a constant vapour quality x = 0.3. The strong HTC dependence from the saturation temperature - up to a factor 6 - is evident and should be carefully taken into account when designing detector evaporators. As a guide for the plot interpretation, it should be noticed that a detector surface power density of 1 W·cm-2 corresponds to a heat flux of 32 kW·m-2 for a single pipe evaporator with ID=1 mm and to a heat flux of 16 kW·m-2 for ID=2 mm. The comparison of the experimental data with some of the most relevant correlations largely used for HTC prediction confirms that the designers should approach those correlations with extreme care and large safety margins. The measurement activity will be extended to stainless steel pipes with different ID, as well as to Titanium pipes, with the objective of providing the designers with reliable guidelines to be applied to all cases of interest for future detector design. Thermal measurements were also conducted in parallel on a micro-fabricated silicon cold plate coupled to a realistic mock-up of a silicon chip. These tests provided a quantitative confirmation of the unparalleled thermal performance of micro-channel silicon cold plates, showing a reduction of a factor ~4 of the temperature difference between the refrigerant and the heat source with respect to the best result obtained with a tubular evaporator embedded in a highly conductive carbon foam. In addition, the observations conducted with a High Speed Camera, made possible by the specific fabrication process adopted for the silicon cold plate, featuring an optically transparent Borofloat® plate opposite to the silicon one, provided very useful hints to work on a physical explanation of the previously described effect of saturation temperature on the HTC of CO2. As an example, the figure below reports two images taken on the same cold plate in the region of boiling inception at saturation temperatures of +15 °C and -25 °C, at the same heat and mass fluxes. The difference between the two boiling patterns is striking and, although obtained on a very different geometrical configuration, can also be used to explain the difference of thermal performance observed in simple tubular evaporators at the same temperatures.
49
High Speed Camera images showing the difference of pattern at boiling inception between a saturation temperature
of +15 °C (top) and of -25 °C (bot), all other parameters being equal.
Cooling System R&D
Important progresses were made during the year on the production of a numerical code for the dynamic simulation of complete CO2 cooling systems. A new library of components specifically designed for the simulation of two-phase flow circuits in the EcosimPro physical modelling platform was created. The library was successfully validated against well documented test cases, and then used to model and simulate the dynamic cycle of a test bench reproducing the CO2-based two-phase cooling systems used for silicon trackers.
Comparison of simulation and measurements for the startup of a detector CO2 cooling system. Dotted lines represent
measured data and solid lines represent simulation results.
50
The staggered grid method and the upwind scheme have been adopted to handle splitting and merging flows along with flow reversals. Slip-ratio based void fraction correlations have been accounted for to better account for two-phase flow. The simulated results were compared against measured data collected from the test setup, showing good fidelity. As an example, the results for the simulation of the complex startup procedure are plotted in the figure below. The controller is set to attain a set point temperature of -20°C with 2 kW of thermal load. It can be seen that the simulated values match well with the experimental ones. The larger discrepancy is visible in the plot (c), where the simulated heater wall temperature in the evaporator overshoots the measured value during the initial startup. This is attributed to the use of a constant heat transfer coefficient employed for the sake of solver robustness. Appropriate complex correlations will be implemented at a later stage if necessary, although the underlying trend is captured. Set-point change transients have also been simulated, and the simulations are able to predict changes in the pump temperature caused by reduced capacities in the condenser. The developed tool shows readiness for use in the design of the next generation of silicon tracker cooling systems.
Optical Fibre Thermo-hygrometry
Multi-point sensing by LPG sensors Following the previous gamma irradiation studies, during 2018 three high fluencies proton irradiation campaigns have been executed in the IRRAD facility on LPG sensors produced by excimer laser on a standard B-Ge doped fibre. Some of the sensors were uncoated (sensitive to temperature) and some others were coated with an optimized nano-layer of TiO2 (sensitive to temperature and relative humidity). The functionality of the sensors showed no deterioration for doses above 1 MGy and fluencies above 5x1015 1MeV neq/cm2. However, while the uncoated sensors exhibited a dose-dependent baseline-shift but no influence on the temperature sensitivity, the relative humidity sensitivity of the coated sensors showed a dependency from the absorbed dose. The dependency observed seems compatible with compaction phenomena of the TiO2 nano-layer, not foreseen by standard Fluka models. New detailed predictive models are presently being developed and will be tested against further irradiation campaigns. Following a complex phase of preparation, at the beginning of LS2 two sets of LPG and FBG sensors, coated and uncoated, produced by different techniques and on different kind of fibres, have been installed behind the ATLAS IDEP: one set on the a-side and one on the c-side. They will be used to provide complete thermo-hygrometric data for the ATLAS ID, and to study in detail the long-term in-field behaviour of different classes of sensors in preparation of a much widespread installation in the ITk detector during LS3. The in-situ calibration process of the 18 sensors installed is presently ongoing. Continuous sensing fibres A first series of thermo-hygrometric tests have been conducted, in collaboration by EP-DT-FS and the Group for Fibre Optics (GFO) of EPFL, on the third generation of temperature and humidity sensors based on fibre optics. In this new developement the fibre itself is the sensor, producing a continuous signal along its full length that can be interrogated for distances up to few km. This innovative technology, once engineered will have the potential of providing detailed thermo-hygrometric monitoring in very large environments and/or very complex geometrical situations with just one long fibre (or two paired fibres). In this first campaign, a length of 650 m composed of 14 segments of different fibres with different coatings was produced. The tests were conducted in a large climatic chamber at a constant temperature of 27.5 °C and relative humidity varying between 12% and 21%, allowing for comparing the sensitivity and the response time of different potential solutions, and preselecting the best candidates for the following phases of more detailed tests and analyses.
51
5.5. R&D on Gas Systems Roberto Guida and Beatrice Mandelli
The research for the development of gas systems technologies applied to particle detectors continued during 2018. A long-term strategy aiming in reducing the greenhouse gas consumption from particle detection was proposed bringing together the needs from all the LHC experiments. Dedicated funds were allocated by the CERN Environmental Protection Steering board (CEPS) for the period from 2019 to 2026. The project articulates around four research lines: optimization of current technologies, gas recuperation plant, new environmentally friendly gas mixtures and gas disposal. Optimization of current technologies Several gas systems upgrades have been evaluated to cope with new detector requirements like enhanced stability, increase of recirculation fraction and flows. In particular, for the RPC detector, new regulation valves and modifications of the distribution module have been tested for improving the pressure regulation. Gas recirculation optimization studies were also ongoing for GEM detectors operated with CF4 based mixture. Tests in different gas system configurations were performed at the CERN Gamma Irradiation Facility (GIF++) for ageing studies and measurement of muon detection efficiency in presence of background radiation like the one expected during operation at the LHC experiments. Ion Selective Electrodes (ISE) for Fluoride ions were used on ALICE-MTR, CMS-RPC and LHCb-GEM to study possible optimization of gas mixture flow distribution in detectors and of mixture purification. Fluoride ions are produced by decomposition of perfluorocarbons or hydrofluorocarbons during detector operation especially under high radiation background. In total 10 setups were installed. The concentration of Fluoride measured at the detectors output is proportional to the detector integrated charge and beam luminosity.
Fluoride concentration measured at the detector return as a function of time compared with the LHC integrated
luminosity.
Gas recuperation plants The development of gas recuperation plants is the second step towards an optimized consumption. Gas recuperation plants aim in extracting greenhouse gases from the exhaust of gas recirculation systems allowing further re-use. Encouraging results have been obtained for the R134a recuperation with a prototype (see following Fig.) connected to the ATLAS-RPC gas system. A R134a recuperation efficiency close to 100% was achieved and the recuperated R134a was as pure as the new gas used for the operation of the RPC system. The research will continue for completing the design of the first system and for understanding the filtering capacity with respect to RPC specific impurities. Considering that R134a dominates the greenhouse gas consumption from particle detection at the LHC experiments, this plant might have an important positive effect on the overall optimization process.
52
First prototype of the R134a recuperation plant successfully tested on the RPC detector system.
New environmentally friendly gases For future long-term detector operation, R&D studies are ongoing to find “green” alternatives to the currently used gases (especially for R134a). Unfortunately, the new alternative gases developed by industry as refrigerant fluids (in particular Hydrofluoroolefins HFOs) are behaving differently with respect to R134a in particle detectors. Moreover, since most of the infrastructure (i.e. high voltage systems, cables, front-end electronics) as well as the detector itself cannot be easily replaced, finding a suitable replacement of the R134a for the RPC systems at the LHC experiments is particularly challenging. During 2018, the research about RPC detector operation with gas recirculation system and new environmentally friendly gases continued at the GIF++. For the first time, RPC detectors were operated with HFO-based mixture during test beam in presence of high gamma background. Despite the encouraging results obtained with a partial substitution of the R134a with HFO-1234ze and the addition of a neutral gas (for example CO2), a final satisfactory solution is still far from being achieved for the LHC experiments.
RPC detector efficiency (continuous line) and streamer probability (dotted line) curves for different background radiation levels (ABS) with the currently used mixture (left) and one of the new environmentally mixture tested
(right). In the case of the new mixture it is visible the higher voltage needed and the shorter width of the working region with low streamer probability.
53
Gas disposal The present strategy for reducing the emission of greenhouse gases consists in the possibility of using industrially developed plants for the disposal of these gases by decomposition in harmless compounds. A feasibility study was carried out in collaboration with CMS. Gas disposal systems allow to abate gas emission in the atmosphere, but they do not consider the gas usage optimization and, therefore, problems like gas availability and price for detector operation might become the challenge in the coming years due to the greenhouse phase down policy.
5.6. Microfabrication Technologies Alessandro Mapelli
The DT group continued to support LHC and non-LHC experiments in microfabrication technologies and microsystems engineering and assisted many CERN users in microfabrication activities in external silicon-processing facilities. In 2018, this included activities for the upgrades of ATLAS and LHCb (see section 2.4.1.), the NA62 experiment (see section 3.2.2.), Pixel R&D work (STREAM) and studies in the context of the FCC, as well as the fabrication of devices for beam instrumentation and monitoring. For the ATLAS ITk studies a process has been defined to fabricate TiN based silicon micro heating devices, that can be used for thermal mock-up studies. These devices are fabricated in the EPFL cleanroom described in the following section and have a short turnaround time between two to three weeks. DT provides the interface to the EPFL cleanrooms (EPFL Physics Institute (IPHYS) and the ISO 5 MEMS cleanrooms of the Center of MicroNanotechnology (CMi)) for CERN users and works closely with the laboratories at EPFL2. The team provides support in the design of devices, the definition of the fabrication process-flow as well as in the follow-up and assistance during the fabrication. It provides also administrative support, training to CERN personnel for their work in the EPFL cleanrooms and centralized handling of the billing. In 2018 six projects from CERN were presented during the poster session of the CMi Annual Review Meeting which was attended by more than 600 academic and industrial participants. Examples of successfully fabricated devices in the EPFL cleanroom
- Devices for the characterization of particle detectors by electrical injection TCT
The Transient Current Technique (TCT) is used for the characterization of silicon detectors.
The first devices to demonstrate this novel approach were fabricated at CMi and
successfully characterized at CERN, showing a similar response of the el-TCT structures
compared to the standard TCT structures which use a short-pulsed laser to inject the
charge [4].
- Embedding microfluidics into microelectronics
A CMOS-compatible microfabrication process was developed at CERN to embed
microfluidics into silicon dies. This process allows to fabricate cooling microchannels on
the backside of monolithic pixel detectors. A demonstrator is currently being produced by
post-processing functional MALTA chips [12] at CMi (see section 5.2).
2 LMIS4 - Microsystems Laboratory (lmis4.epfl.ch),
EDLAB - Group of Electron Device Modeling and Technology (edlab.epfl.ch), IPHYS - Institute of Physics (iphys.epfl.ch), CMi - Center for MicroNanotechnology (cmi.epfl.ch)
54
(a)
(b)
(c)
(a) Simplified process-flow for the fabrication of buried microchannels on the backside of a monolithic pixel detector. (b) SEM image of buried microchannels. (c) 3D-printed connector with plastic capillaries glued to a
100 µm thick MALTA chip.
- Silicon microchannel cooling frames to further reduce the overall material budget,
removing the center region of the cooling plate.
- Fabrication of Proton Beam Profile Monitors for IRRAD as well as for the Future Circular
Collider at CERN (see section 7.1.3. for details).
- Post-processing of Deep diffused avalanche photodiodes (APDs) for charged particle
timing applications (see section 5.1. for details).
- Thermal mapping of superconducting cavities – DT is providing support to the BE and TE
departments for the development of Transition Edge Sensors on glass substrates in the
EPFL-CMi cleanrooms.
Recently, a collaboration has started between CERN, EPFL, the Centre Suisse d'Electronique et de Microtechnique (CSEM) and the Swiss Space Center (SSC) aiming at developing passive self-contained cooling plates. They consist of fully integrated silicon-based micro oscillating heat pipes (µOHP). An oscillating heat pipe is composed of a single microchannel partially filled with a liquid meandering back and forth between a heat source (e.g. pixel sensor) where the heat is extracted by local evaporation and a colder region where condensation occurs as shown on the left drawing of the Fig. below). µOHPs have been identified as the most promising heat pipe configuration for the thermal management of pixel detectors and other semiconductor devices in HEP experiments and for aerospace equipment. They allow seamless operation independent of the orientation and gravity guaranteeing a high thermal conductivity, a fast thermal response and a low material budget. Moreover, they do not require any fluidic connection to a primary cooling plant. This reduces the risk of leakage and intrinsically increases their robustness. The first micro-fabricated prototype of µOHP is shown below. It consists of 400 µm deep micro-channels etched into a silicon substrate and closed by a glass lid using the cleanroom facilities of CSEM and CMi. The dual hydraulic diameter of each U-turn guarantees stable operation independent of the orientation and of the gravity (see the right picture below).This µOHP is currently being characterized at CERN in terms of thermo-fluidic and mechanical performance.
(left) Principle of operation of an oscillating heat pipe. (center) First silicon-glass micro oscillating heat pipe
fabricated at CSEM and characterised at CERN. (right) Detail of the dual-diameter microchannel.
55
6. Services Provided by DT
6.1. Gas Systems Roberto Guida
The activities on the 40 LHC and non-LHC gas systems were driven by preventive maintenance and preparation of consolidations and upgrades in view of the LHC Long Shutdown 2 period. Standard maintenance activities and monitoring of gas systems are fundamental to maintain the usual reliability level (99.98%). During 2018, 150 piquet interventions and about 1000 checks and interventions for scheduled maintenance and monitoring of the systems were recorded. In addition to the standard routine maintenance, power supplies, pressure sensors and pneumatic lines were the target of specific maintenance programs. About 60 power supplies are used for the gas systems operation. A replacement campaign started and about one-third were replaced with a new generation. For the LHC gas systems a total of about 1000 pressure sensors are used, of which about 500 are in gas distribution modules located in the experimental caverns. Even though in many cases a redundant sensor is present, the sensors reliability is of fundamental importance because the measurements are used to regulate the gas mixture pressure in the detector. During 2018 few problems were observed in sensors particularly exposed to radiation and in view of the expected LHC luminosity increase, a dedicated study was organized. Several types of pressure sensors, flow meters and a gas analyser were tested at the CERN High Energy Accelerator Mixed field facility (CHARM), which is the best place for validating electronic components for the LHC experiments. The results clearly indicated that only a specific generation of pressure sensors was able to guarantee good performance all over the expected period and a dedicated production was agreed with a company. After more than 10 years of operation, the pneumatic lines used to control valves in the experimental caverns have largely exceeded the expected lifetime and considerable leaks started to appear. The replacement campaign which started in the past with LHCb and ATLAS, continued during 2018 in CMS. About 2.5 km of multitube pipes (equivalent to about 10 km) were installed only for CMS. Gas chromatographic analysis were performed on a regular basis to verify the gas mixture composition during detector operation for the LHC experiments. In total 3 instruments were used to monitor the mixture for 8 detectors at the LHC experiments (in total 14 analysis points). In addition to the web page summary, since 2018 all data were distributed over DIP to the experiments. A detailed plan was prepared for upgrades and maintenance of the LHC gas systems during LS2 combining activities, available resources as well as the specific needs of each experiment. About 30 consolidation and upgrade projects have been included. A special maintenance program has been established. In total about 750 weeks have been allocated in the LS2 planning including CERN staff and Field Support Unit personnel. If compared with the construction time needed for a medium size gas system, the LS2 workload is expected to be equivalent to the construction of about 10-15 new systems (i.e. about one-third of the current infrastructure for the LHC experiments). Maintenance activities represent 40% of the total. The remaining 60% is due to upgrades and new gas systems. For example, 8 distribution modules were extracted from the CMS experimental cavern to be modified according to new RPC requirements and for including the new CMS-GEM distribution modules. Four additional modules have been designed for ATLAS-RPC. The new gas systems for CMS-GEM and LHCb-SciFi flushing were designed during 2018. Concerning the non-LHC part, the gas team continued to be involved in the maintenance, operation and development of the CLOUD, LINAC4, NA62, GIF++ and 904 gas systems. About 150 interventions were recorded during 2018. Technical and design support was granted to many CERN users and other CERN experiments.
56
6.2. CO2 Cooling Systems
Cooling coordination with LHC experiments
Paola Tropea, Lukasz Zwalinski The ATLAS cooling system operation in 2018 was rather stable apart from few issues addressed during technical stops. The main issue has been again the leak in Tile Calorimeter cooling system due to malfunctioning and edging connectors inside the detector and leak in TRT. A major improvement has been foreseen for LS2 including the replacement of all fast connectors of the Tile Calorimeter. Additionally the ATLAS cooling team together with EN-CV is studying the possibility of installing new pneumatic valves to be capable to insulate easily a leaky cooling circuit, in order to minimize the impact on data taking. The ATCA crates thermal tests are well continuing: the first 3m tall racks have been installed in ATLAS counting room (USA15) and are ready to receive first ATCA electronics during the LS2. The ATLAS Thermosiphon was performing very well after the final condenser replacement. The system ran stably for long term during summer 2018, and number of tests were carried out. The automatic swap between compressor stations back and forward has been validated. After the final tests with the detector during TS2 and the endorsement of ATLAS EB, the Thermosiphon has been put in operation with the ID for the last period of Data Taking and became the main ID cooling system until LS3. In 2018, the ATLAS cooling team together with EP-DT and EN-CV has completely rebuild the CO2 SR1 cooling station with state of the art technologies used nowadays for CO2 cooling systems. (New chiller, new accumulator, new control system logic for both PLC and SCADA, new transfer lines in SR1 radiation lab.) This will serve to all ITk detector R&D activities for Phase II in the extended SR1 clean room. During 2018, the activity of the CMS cooling coordination team has mostly focused on the preparation of the LS2 activities, both for water circuits and the future Phase II CO2 cooling circuits. In order to accommodate for the new requirements of the Endcap Muon detectors, a study has been completed and the specification for the water-cooling system to operate few degrees lower in temperature has been handed over to EN-CV, who has implemented the changes during the first months of the LS2. The maintenance activities on all cooling systems, perfluorocarbons, CO2 and water, have been scheduled according to the less disruptive timing with respect to the CMS detector LS2 activities and backup systems foreseen when needed. For the CO2 cooling of the Tracker upgrade, the Calorimeter Endcap and the Timing Layers, the integration office of CMS has been fed by the cooling team with all the specifications needed: envelopes of the cooling plants and preliminary sizes of all the concentric transfer lines, designed by a fellow of the FS section. As of 2018, the responsibilities of the DT-FS section for maintenance and operation of CO2 cooling systems for operational detectors has been extended to the ATLAS IBL system. The operation of both experiments has been smooth and has requested no corrective maintenance interventions, allowing full time operation of the two detectors. In 2019, the LHCb Velo and UT cooling systems will be part of the M&O service as well.
Construction of new cooling plants
Paolo Petagna, M. Brodski and P. Tropea for the DT-FS Cooling Team MAUVE The MAUVE (Multiple Apparatus for cooling of UT and Velo Experiments) cooling system, featuring
two identical CO2 plants (7 kW of cooling power at -35C each) for the upgrade of LHCb Velo and UT has been fully built in 2018. Commissioning has started towards the end of the year, with the installation for the two plants and their independent backup chiller in the new cooling laboratory
57
of building 153. Verification of electrical connections through the automatic logic have been performed as first step, followed by the plant operation and its performance evaluation. Engineers and students from the cooling team and a physicist of the DT section are completing the process in the first months of 2019, in order to install a fully commissioned plant in the LHCb underground premises by summer 2019.
The two plants forming the LHCb MAUVE cooling system under commissioning in the new EP-DT CO2 cooling lab in
building 153
DEMO and future systems The DT-FS cooling team has received the mandate of designing procuring and testing a first
prototype (the DEMO) of the large plants that will form the CO2 cooling systems of the phase II
upgrades of ATLAS and CMS. Following the phase of conceptual design, in 2018 the activity focused
on the procurement of the key components and the engineering design of the first unit. In
particular, the selection of the liquid pump for the DEMO was merged with the procurement phase
of the pumps for all the final systems. Following a Market Survey and an Invitation to Tender, a
contract worth few MCHF was signed with the selected company, securing the programme and
economic conditions for the procurement and the maintenance of all the future pumps. The first
pump, equipping the first DEMO module has been specified with the company and is presently in
production.
The DT-FS section is also looking into finding reliable temperature and pressure sensors which are
resistant to strong magnetic fields and ionizing radiation. Several tests were executes with a
dedicated setup in both magnetic and radiation fields. The corresponding report was presented
and thoroughly discussed during the final FS section meeting of the year. Another setup has been
partly prepared for further tests.
58
6.3. Magnetic Measurements and Controls
The DT-DI and DT-EF sections have a long experience with the instrumentation for magnets, facilities and detector infrastructures. They support experiments and other teams in EP for the choice of sensors, the readout electronics, general electromechanical support, as well as device installations and data treatment.
Magnetic field measurement service
Felix Bergsma
Documentation
In order to make equipment usable for non-experts an inventory was done and documentation
inspected. For the production of magnetic sensors this concerns the precision mounting of the
Hall probes on a glass cube and wire wrapping of their contacts, which have been documented.
The calibration station is already automatic and a step by step user’s guide is in preparation.
Manuals for measurement benches and data acquisition systems are prepared or upgraded.
Wire wrapping Hall probes
Sensor production
Calibration of 200 B-sensors for ATLAS-NSW and 20 for Mu2e is finished. Production and calibration
of 80 B-sensors was done, 60 are for MPD, 6 for HL-LHC and 14 spares. 20 old sensors with BATCAN
modules were delivered to ALPHA. 100 upgraded B-sensors were ordered.
Benches
Three pneumatic motors were produced at CERN, including the housing made of aluminium. The
device for mapping the MPD magnet is under test in building 164 and operational. Some cabling
and maintenance have to be done and planned to be finished end of June 2019.
The new Cartesian bench is under construction in building 164, the pneumatic motors are tested.
The cabling of the cylindrical and Cartesian benches was improved, which makes the control
modules easy exchangeable.
Mappings
The magnetic field of the MICE Spectrometer and Absorber Focussing Coils have been re-measured
with the special device build by DT-EF. This was necessary because the old current values of MICE
had changed and material with non-linear susceptibility was present.
59
MICE mapping
Calculation
The NA60+ collaboration needs a magnet similar to ACM with different aperture to study di-
muon events. The windings of the ACM are arranged in a complicated way, which gives an
excellent field quality but makes this magnet difficult to build and expensive. A new minimal
design, easy to build and cheap, but with a more complex field, was proposed. This layout could
also be useful for other experiments. An OPERA model has been made and field values
transferred for MC-studies.
Magnet service area
The magnet service area had visitors from ATLAS, CMS, Neutrino Group and Safety Office for a
total of 47 days magnet time.
Magnet Control and Safety System
Giovanna Lehmann Miotto
The Magnets Control Project (MCP) delivers control and safety systems to the LHC experimental magnets and ensures their operation and maintenance throughout the lifetime of the experiments. Additionally, adapted variants of the systems developed within this framework have been deployed on several other experimental magnets at CERN. The main components of the MCP are the Magnet Control System (MCS), the Magnet Safety System (MSS) and the Magnet Diagnostic System (MDS).
Transition plan from the old to the new MCS system for the ATLAS experiment (left); implementation of the first new
MCS rack for the ATLAS central solenoid (right).
60
The main difference between the LHC experimental magnets and the others is that for the LHC experiments a 24/7 on call service is in place, acting as first line support for the magnets as well as for the detector safety systems. After the successful completion of the MSS upgrade, in 2018 DT-DI started preparing the upgrade of the Magnet Control System hardware that was becoming obsolete, with the aim of exchanging the systems for all four LHC experiments during LS2. In addition, the section supported COMPASS during the re-connection and commissioning of the target magnets for the 2018 run, with new operation modes for the magnets, as well as the disconnection of the magnets and vacuum system required to move the target platform during LS2.
Instrumentation and Controls
Giovanna Lehmann Miotto
Detailed temperature mapping Using the knowledge and experience acquired instrumenting the LHC experimental magnets, EP-DT-DI has developed a multichannel and very precise temperature readout system, capable of reading out hundreds of temperature sensors at ±1 mK accuracy. This device is equipping the ProtoDUNE Single Phase and Dual Phase experiments, as well as CLOUD. In ProtoDUNE, reading many temperature sensors installed on vertical profiles inside the LAr Cryostat allows to build a precise 3D temperature map that is used to validate the fluid dynamic simulations and ensure a good understanding of the cryogenics system.
One of the ProtoDUNE Single Phase temperature profiles installed in its final position inside the cryostat. b) ProtoDUNE Dual Phase DT-DI Temparature Readout System. c) ProtoDUNE Single Phase LAR temperature as a
function of the distance from the bottom of the cryostat.
Capacitive Level Meters
The Liquid Argon Level is an important parameter to be measured precisely and regulated inside the cryostats of the neutrino experiments; in particular, this parameter is critical in the Dual Phase
61
detector, since it affects proper detector operation. The industrial market already proposes technical solutions based on capacitive level meter devices, but they are either technically not applicable or they are too expensive. For that reason, starting from an idea proposed by F. Resnati (EP-NU), DT-DI has developed an electronic interface that, independently of the cable length, allows an accurate reading of the capacity variation (due to the dielectric constant of LAr) of 2.5 cm long capacitive level meters. This system is being used in the ProtoDUNE Dual Phase detector for reading up to 20 level meters installed around the Charge Readout Plane (CRP) modules for their correct positioning and transmitted to the cryogenics system for an accurate regulation.
Capacitive level meters electronic interface developed by DT-DI (left); NP02 CRP detector equipped with two
capacitive level meters (right).
Strain Gauges
The NP02 and NP04 detectors are embedded in cryostats which have the capacity to hold around 700 ton of Lar at a temperature of about 87 K: they consist of a steel warm outer structure, layers of insulation and an inner cold membrane. Filling an empty structure with hundreds of tons of liquid will inevitably present a big load on the walls and will cause it to mechanically deform. To get an estimate of the magnitude of these deformations FEA models of the cryostat have been developed to assist in the choices of the mechanical design of the structure. It is however important to carry out actual measurements of the deformations before, during and after the filling process as this allows to check the actual structural behavior under various load cases and allows to check the predictions of the FEA models and correct them, if necessary. Having a live measurement of the deformations is also a safety aspect as any abnormal structural behavior during the filling process would most likely be seen by deformation sensors on the cryostat
ProtoDUNE Single Phase strain gauge measurement; b) and c) DT-DI strain gauges interface prototype connected to
the NP04 Strain gauges system.
The NP04 has been equipped with about 60 strain gauges in order to measure the deformations, during the commissioning period, with a commercial device. The importance of being able to provide strain gauge measurement systems to a variety of experimental setups has prompted DT-DI to start a project for the development of a readout system supporting a large number of sensors
62
at reduced cost, including the aspects of signal analysis and interpretation as well as the integration of the data into the detector control system (for visualization, setting of alarms and archiving). At present, DT-DI is using the disconnected NP04 strain gauges for testing the prototype electronic interface. The Curious Cryogenic Fish
DT-DI started an R&D project in 2018, together with the Neutrino Platform, TE’s CryoLab and the Danieli Telerobot company to study the feasibility of creating a robotic device, able to move in a cryogenic medium (e.g. a cryostat) for diagnostic purposes (e.g. visualization). The research started mainly through the work of a graduate and a PhD student and focused on one hand on the visualization aspects (cameras) and on the other hand on the shell of the robot and on propulsion and motion control techniques, with the collaboration of DT-EO. A project was submitted for funding to the EU ATTRACT initiative and the application was successful, such that in 2019 we hope to push on the research further also on several other challenging aspects of the project (e.g. energy harvesting and storage). Other Control Systems In addition to the systems highlighted above, for which there were major developments carried out in 2018, DT-DI also supports other control systems, such as the roman pots movement and vacuum control systems (TOTEM, ALFA, AFP), the NA62 safety system, the GiF++ infrastructure control and monitoring system, and CAST.
6.4. DAQ Systems Enrico Gamberini and Giovanna Lehmann Miotto
The support for developing DAQ systems for experiments and detectors is a recent activity in DT. It started after the EP management established the need for offering this kind of service to the community, in 2015. Two use cases were selected in 2016 as initial “customers”, in order to find the best working model for supporting experiments in an aspect that is at the core of the experiments themselves, i.e. the acquisition of physics data: NA62 and NP04 (see section 4.2.2). After the successful completion of these projects, several other contacts have been established with experiments and R&D communities. In order to remain up-to-date with the latest technologies and trends of DAQ systems, DT-DI is working in close collaboration with industry and the LHC experiments. As an example, a joint R&D project with Intel and the LHC experiments on large distributed key-value stores for DAQ is ongoing, in the framework of CERN OpenLab. DAQ support is provided in terms of a collaborative effort with the experiments. For systems that need to be developed, DT-DI advises on viable design choices, suggests suited toolkits for the implementation of functionality and carries out joint development of the aspects that need to be tuned specifically to the needs. The aim is to allow the experiment communities to remain the owners of the DAQ system and to actively participate to its shaping. For existing systems, DT-DI can assist in identifying issues, reviewing designs and implementations and can help in the development effort needed to achieve the desired performance and/or functionality. The continued and successful collaboration with NA62 on DAQ matters prompted the launch of an R&D study in 2018, in collaboration with EP-ESE, for the upgrade of the NA62 front-end electronics and readout system. While EP/ESE-FE is designing a new Time-to-Digital Converter (TDC) board to replace the current front-end electronics, DT-DI is implementing a new readout, based on the ATLAS FELIX system. The new TDC boards will be connected via fibers to powerful servers hosting one or more FELIX cards. These servers will perform the data selection, formatting and forwarding, based on the received triggers from the experiment.
63
Sketch of the new trigger-less readout system for the CHANTI and KTAG detectors of the NA62 experiment. Any hit detected in the detectors is sent to the FELIX system and buffered on host memory. For the KTAG detector, data are forwarded to the PC farm upon a L0 trigger accept, while the data of the CHANTI detector need to be forwarded to
the event building system only upon a L1 trigger. The FELIX (FLX) card is also in charge of distributing Timing, Trigger and Control (TTC) signals as well control and configuration commands to the front-end electronics.
The goal of this joint effort is to demonstrate, at hand of two of the most demanding detectors in terms hit rate (KTAG, CHANTI), the capability of reading out all hit data, even beyond design intensity of the beam, without relying on the data reduction achieved by the L0 trigger nor requiring long buffering on the front-ends. The main challenges for the readout system are the handling of a very high rate (order 10 MHz) of small data fragments (order 64 bits) delivered in a not time-ordered fashion from the TDCs, combined with the real-time processing needs, to time match data with trigger requests (~1 MHz), aggregate and format hits into larger DAQ fragments, and send them to the PC farm. DT-DI is investigating methods to perform this challenging selection in software and will collaborate with EP-ESE-FE to perform the interfacing tests between the first TDC boards and the FELIX card, including the data path and TTC signals in 2019. If the R&D is successful, the KTAG and CHANTI detectors will be equipped with this new system from the start of data taking after LS2.
64
7. Infrastructure for Detector R&D
7.1. Irradiation Facilities
Gamma Irradiation Facility (GIF++) at the SPS North Area
Martin Jäkel for the DT-DD Irradiation Facilities team
The CERN Gamma Irradiation Facility (GIF++) is a joint EN- & EP- Department facility located on the H4 beamline (Zone PPE-154) in EHN1. It is a unique place for detector R&D tests where a strong gamma source and a muon particle beam are simultaneously available. The facility provides two independent radiation fields, each one equipped with an attenuation system of iron/lead filters, with the purpose of optimizing the gamma field for the required tests. The facility is equipped with excellent gas and electronic infrastructures, a unified control- and monitoring system, setups for beam- and cosmic- trigger as well as radiation- and environmental conditions- monitoring.
GIF++ irradiation bunker during the last muon beam time before the LS2. Left side is the downstream irradiation
field, on the right side the upstream irradiation field. A record of 11 setups – often consisting of multiple chambers – could be placed simultaneously in the muon beam.
The facility is intensively exploited by a large collaboration from the LHC experiments. The main detector R&D programs remains the upcoming upgrades of the Muon systems for the LHC experiments in view of the High Luminosity LHC phase. This includes eigth different gaseous detector technologies: Drift Tubes (DT), Gas Electron Multiplier (GEM), Cathode Strip Chambers (CSC), MicroMegas (MM), Resistive Plate Chambers (RPC), glass based Resistive Plate Chambers, Thin Gap Chambers (TGC) and Transition Radiation Detectors (TRD). 2018 was an especially challenging year with more than 22 full-size setups requested long-term irradiation, and 16 setups – often consisting of multiple chambers - requesting muon beam in the final year before the Long Shutdown 2. A total of 7 weeks of dedicated muon beam could be provided and was successfully shared with the RD51 collaboration hosted beam upstream. With the help of the user community, we managed to host a record of 11 setups simultaneously in the muon beam, while still providing stand-alone gamma irradiation for several other setups. Results obtained by each group have been presented at international conferences.
65
The last part of the year was dominated by several mass production test campaigns, starting immediately after the last muon beam. From the ATLAS New Small Wheel (NSW) project, both MicroMegas and small-strip TGC production chambers arrived. Validation of chambers will continue throughout 2019 with multiple chambers entering / leaving the irradiation bunker every week.
s First ATLAS-MM chamber (NSW)to arrive at GIF++ for validation (left). Two ALICE TPC chambers under test to identify
/ repair faulty chamber before installation in the ongoing LS2 (right).
When problems appeared with the first TPC chambers being delivered to ALICE for the ongoing upgrade, GIF++ could provide its gamma field as an excellent test bench to spot faulty chambers so that these could be repaired in time for installation in ALICE. On short notice, we therefore launched an additional validation campaign – testing 6 TPC chambers per week in pairs of two. With more than 60 chambers to be tested, the campaign will last well into 2019, adding to the complexity of the daily user planning.
Proposed extension of the irradiation bunker by 9.6m towards the upstream beam area, which will provide 57m2 of
additional irradiations area in a dedicated low-irradiation zone.
66
The space along the muon beam path became a major limiting factor for hosting additional set-ups or allowing proper access to installed chambers for the ever-growing user community at the GIF++. In addition, requests for lower dose validation tests (lasting several months per year) conflicted with the simultaneous strong demand for high dose ageing studies. We therefore started to investigate if an extension of the irradiation bunker could be feasible, creating a dedicated low irradiation zone while also providing additional space along the muon beam path. An Engineering Change Request (ECR) for an 9.6 meter long bunker extension (adding 57m2 of irradiation zone, see Fig. above) was submitted (SPS-EA-EC-2018-0001) and with the support of all four LHC experiments, as well as the EP and EN departments, funding for this project could be secured. As the additional space will already be very beneficial for the ongoing mass production tests, construction will start in early 2019 in parallel to the continuous operation of the facility throughout the LS2. In October, we held the second Annual GIF User Meeting, with talks covering the various aspects of the infrastructure as well as presentations form all user groups active during 2018. Several GIF++ users profited from financial support provided through the AIDA-2020 Transnational Access program.
Proton (IRRAD) & mixed‐field (CHARM) Irradiation Facilities at PS East Area
Federico Ravotti for the DT-DD Irradiation Facilities team
The proton irradiation facility (IRRAD) at the PS East Area was built during LS1 to cope with the increasing need for irradiation tests of the community working for the HL upgrade of the LHC and beyond. This new facility is the natural upgrade of a historical service in the EP department that, since the 90’s, exploits the 24 GeV/c proton beam of the CERN PS for studying the radiation hardness of semiconductor devices (RD50) and materials. The IRRAD facility, operated by EP-DT, is part of a more complex infrastructure in the PS East Area that includes, on the T8 beam-line, also the mixed-field facility CHARM operated by the EN department. The year 2018 for IRRAD, being the last one before the LS2, concluded successfully the first run of this facility which is operational since the LS1 with more than 2500 samples irradiated (see also EP-newsletter article of December 2018). During this year, the IRRAD team was exposed to a high pressure arising from many of the user teams that needed to perform the last, crucial, irradiation experiments before installing their equipment in LS2. About 1000 samples have been registered by the users in the IRRAD data manager software application. Finally, as shown in the following Fig. (left-hand side) during 2018: 792 objects, belonging to 92 users and 81 different experiments were irradiated and more than 600 dosimetry measurements were performed during the 227 days of proton beam operation. 47% of the irradiated samples came from the LHC experiments, 28% from R&D projects (RD50/RD53/etc.), while 25% of them belonged to the Accelerator and Technology (A&T) sector, various EP groups and small experiments. The most complex irradiation experiment performed during 2018 was the FEAST2 DC-DC converters test. The failure of this component represented an immediate threat for the data taking 2017 of the CMS experiment but also risked to compromise many other future projects that already integrated this device in the design of the power distribution network of their detector systems. This experiment, carried out in IRRAD with an "ad-hoc" experimental setup, was critical for understanding and solving this issue as documented here: http://project-dcdc.web.cern.ch/project-DCDC/public/Reports.html. The two irradiation runs for the FEAST2 experiment consisted in the insertion of a thin (10 mm-thick) copper target in the proton beam in order to simulate the exposure conditions of the devices installed in the CMS pixel, as shown in the following Fig. (right-hand side). In parallel to the irradiation performed in IRRAD, 61 users, mostly belonging to the EN/TE/BE department at CERN or coming from the experimental sector or from external collaborations (≈20% for each category), installed and run experiments in the CHARM mixed-field irradiation area. Moreover, 21 days at the end of the run 2018 were dedicated to the development and commissioning of a Pb-ion beam on the T8 beamline. In this context, several dosimetric measurements where performed by the IRRAD team
67
aiming to characterize a beam for Single Event Effect (SEE) studies in electronic components for space applications, but also to propose a Heavy Ion (HI) beam to the users of the EP experiments for the second run of the facility after the LS2 (from spring 2021 onwards). During 2018, the proposal for the extension of the IRRAD technical area during LS2 (EDMS 2085649) was also finalized and accepted by the involved groups in EP, EN and HSE department. While the year 2019 will be dedicated to the thorough maintenance and upgrade of the various irradiation systems suffering from radiation-induced degradation (see also AIDA-2020 D15.7 deliverable report: https://cds.cern.ch/record/2663195), the beginning of the works in bld. 157 for the extension of the IRRAD technical area, are currently scheduled in the first half of 2020. Among the upgrades foreseen during the LS2, one concerns the IRRAD Beam Profile Monitor (BPM) devices. The advancement in the microfabrication processes carried out for the RDR dosimeters (see section 7.1.3), triggered the idea of adopting the same technology for the development of a new generation of BPM devices for IRRAD less prone to radiation damage and more "transparent" to the proton beam. During 2018, several prototypes of these new BPMs were manufactured at EPFL and tested in the framework of the AIDA-2020 task D15.7 in IRRAD. The very promising results (see AIDA-2020 Technical Note https://cds.cern.ch/record/2655341) indicate the feasibility of this approach.
Statistics for the IRRAD facility during the run1 (2014-2018) on the left-hand side. Pictures of the complex
irradiation experiment performed for the FEAST2 DC-DC converters test, along with the simulations performed to predict the secondary field produced by the thin Cu-target on the right-hand side.
IRRAD is also part of the AIDA-2020 Transnational Access (TA) to irradiation facilities program that provides funding for external users to perform their irradiation tests at CERN. In total, 18 projects and 76 users where supported by the AIDA-2020 TA during the first run of IRRAD. Since detector and accelerator developers need irradiation facilities to test their components under conditions that are as close as possible to real applications, and even more now during the LS2 without the availability of most of CERN irradiation facilities, the new database of worldwide irradiation facilities was maintained and expanded by the IRRAD team in 2018. With more than 210 entries at the end of 2018, this is a unique database of this kind worldwide. More details about this development within AIDA-2020 are available on the EP-newsletter article of April 2018. Within the AIDA-2020 framework, and in collaboration with the MINES ParisTech in Paris, the new IRRAD Data Manager (IDM) software application has been further developed and used for the follow-up of all irradiation experiments of 2018 in IRRAD. Along with this new software tool, the formalization of an “Ontology for Irradiation Experiment Data Management (IEDM)” has been also completed. In the future, IEDM will be used as a base for automatic code generation for the data management systems of any kind of irradiation facility (along with other machine learning applications).
68
Radiation Monitoring Sensors (RADMON)
Federico Ravotti for the DT-DD Irradiation Facilities team
The PH-RADMON integrated sensors monitor radiation levels at the LHC experiments that may cause damage to sensitive electronics equipment and particle detectors. During 2018, 11 new PH-RADMON devices were assembled for the CMS-GEM project and configured with different types of RadFET and pin-diode devices. Moreover, to cope with the decreasing number of sensors in stock, a new batch of 200 sensitive pin-diode devices was procured during the year. A general-purpose and portable readout system for these sensors (the “ReadMON”) is under development by the IRRAD team. During 2018 most of the required control software for this device has been developed and the full system has been further validated during several irradiation experiments in IRRAD. Finally, the team provided support to many CERN users for measurements with passive radiation sensors (mainly GaF films used for the cross-calibration of reference PIN diodes for the dosimetry of the X-ray tubes) during irradiation campaigns inside and outside CERN. The silicon-based devices employed in the PH-RADMON sensor proved to be the right choice for the LHC. However, the HL-LHC upgrade and future hadron colliders such as the FCC are expected to generate an unprecedented amount of radiation, posing new challenges for radiation monitoring. As a possible new technology for ultra-high level particle fluence monitoring, the IRRAD team (in the framework of the FCC Radiation Hardness Assurance – Special technologies WP 11, together with the Centre of Micronanotechnology (CMi) of EPFL in Lausanne) has proposed the novel idea to use copper thin films. These nanometre-size copper films exhibit resistivity changes at high particle fluence levels, and can possibly be used as Radiation Dependent Resistors (RDRs).
SEM picture at 50k magnification of a non-passivated and irradiated copper film (let).
The mechanisms involved in the radiation-enhanced oxidation effect (right).
During 2018, we completed the understanding of the basic mechanism underlying the RDR resistivity change, which is attributed to a radiation-enhanced oxidation effect. Further radiation damage experiments were performed on copper thin films of few 100’s nm. After observing an increase of resistance only in copper samples exposed to ambient air, and supported by the finding of voids and oxide grains by cross-sectional SEM analysis, a model describing this phenomenon was developed (see above Fig.). The model, describing the set of chemical and nuclear processes responsible for the copper corrosion in radioactive environments, is the pre-requisite to evolve towards a new reliable sensor technology to be employed in CERN accelerators and experiments. These results have been submitted for publication in the AIP Advances Journal published by the American Institute of Physics.
7.2. Solid State Detector Lab, Bond Lab, QART Lab and DSF
Solid State Detector Lab
Michael Moll
The solid-state detector laboratory (SSD) is located in bldgs.28 and 186 and offers a wide range of measurement techniques to characterize the properties of (irradiated) silicon detectors and perform defect spectroscopy on semiconductor diodes.
69
Available equipment The lab is equipped with a Transient Current Technique (TCT) system with red and infrared lasers delivering light pulses of about 250 ps length on temperature controlled devices under test (DUT)
down to -20C. It is used to characterize the electric field inside silicon sensors and study signal formation in standard- or edge- TCT mode. The system can be modified to allow for precision timing jitter measurements by shining two calibrated infrared light pulses with a well-defined separation in time (50 ns) on the same device. Other available systems are a CV/IV imbedded in a
climate chamber allow measuring sensor characteristics down to -60C and up to 2000V. The same climate chamber holds a beta source (Sr-90) based single-channel charge collection efficiency (CCE) measurement system based on discrete electronics. Multichannel CCE measurements on segmented (strip) detectors can be performed with an Alibava system. For less demanding CV/IV measurements a cold chuck system with probe needles reaching up to 1000V and embedding a
cooling down to -30C is available. The Thermally Stimulated Current (TSC) system, which allows performing defect characterization in the temperature range from 20 K to room temperature by measuring emission currents down to tens of femto amperes was further optimized for precise temperature measurements during the ramping of the temperature in collaboration with DT-CO. New equipment In 2018 the construction of a Two Photon Absorption - TCT ("TPA-TCT") setup has started. The project is funded by a grant from the CERN Knowledge Transfer fund. In contrast to conventional TCT a new femtosecond-laser source with a photon energy below the threshold for single photon absorption in silicon is used. Because light will only be absorbed in the focal point of the laser, it will be possible to characterize detectors with a much increased spatial resolution and for the first time in a real 3D mode. The beam waist will have a width of about 1µm. This development is especially important, following the trend of ever thinner detectors and detectors with implemented read-out circuitry (HV-CMOS). To be able to move the focal point of the laser in the sample accurately, a 6-axis high-precision hexapod will be used (precision 50-100nm). Delivery of the laser and positioning system will be in spring 2019. In 2018 the setup was prepared as far as possible for the delivery of the fs-laser. An optical table, Faraday cage, power supplies and read-out electronics were set up. A conventional laser source (660nm) was used to mimic the functionality of a TCT setup. Furthermore, a Deep Level Transient Spectrometer (DLTS) was installed at the end of 2018 and will be commissioned in spring 2019. Users The SSD equipment is heavily used by the SSD team for detector research, serves visiting scientists from the RD50 collaboration and has been made available as a service to several external groups: colleagues from ATLAS, CMS, LHCb, DT and EN-EL performed measurements for their individual solid-state sensor projects in the laboratory.
Bond Lab
Alan Honma, Florentina Manolescu, Petra Riedler
The wire-bonding lab has been involved in a large number of projects in 2018, owing to the many activities for the LS2 and LS3 upgrades in the LHC experiments. The complexity of the bonding work is increasing over the years due to challenging designs, for example smaller wire bonding pads and geometries, but also due to thinner and larger silicon chips used in the various experiments. The Bond Lab team has provided advice to many projects concerning all matters related to wire bonding layouts and assembly strategies. During 2018 and continuing in early 2019, the entire module production of the ALICE ITS inner barrel modules was carried out at CERN. All optimization and the full wire bonding production as well as systematic wire bond quality testing of 125 modules have been completed in the Bond Lab.
70
In parallel, 100 pre-production modules for the MFT Alice detector have been wire bonded in preparation for the upcoming production. For the installation of the GEM GE1/1 V3 inside CMS forward Muon detectors, the new VFAT3 chip has been developed and was originally planned to be entirely bonded in industry. The CMS project requested the assistance of the Bond Lab in assembling and wire bonding 60 pieces and despite the very short available time, the work was completed successfully and the installation was realized as planned on March 1st, 2018. The production wire bonding for the NA62 GTK modules has continued throughout the year at the rate requested by the project. Within the STREAM EU MC project a novel large area monolithic pixel chip (MALTA) has been developed. The chip contains more than 500 wire bonding pads of 80 µm x 80 µm which are placed with minimum pitch on 3 edges of the chip. The chips are thinned to 100 µm, which causes additional deformation due to the stress in the silicon. Many MALTA chips have been mounted and bonded in the lab, including a chip-to-chip connection which allows data and power transfer directly from one chip to the next without the use of a flex cable. The Bond Lab has been involved in the assembly and wire bonding of the RD53A chip, which is a critical element for ATLAS and CMS pixel upgrades during LS3. This included contact with other institutes involved in the wire bonding of the RD53 chip to help resolve issues observed during the bonding. As usual, there was a very large number of requests from a large variety of clients: LHCb, ATLAS, CMS phase 2 upgrades, Medipix, ESE-DC-DC convertors, TOTEM, RADMON, CALICE, RD50, RD51, etc. Experience and knowledge exchange in the use of the G5 wire bonding machine has been shared with bonding sites inside the high energy physics community.
Wire bonding of a chip
Quality Assurance and Reliability Testing (QART) Lab
Alessandro la Rosa The QART lab provides services to the CERN community supporting projects working on novel detector technologies. The lab is equipped with dedicated instrumentation for QA/QC and reliability testing as environmental chambers, a powerful vibration test system, a small aperture high field (2T) electromagnet, and numerous smaller specialized test equipment used by a variety of users. Examples of jobs are tests for the LHCb RICH upgrade (electronics thermal cycling tests), LHCb VELO Upgrade (hybrid modules thermal cycling and preparation for vibration tests), ALICE ITS Upgrade (modules thermal cycling), EP-ESE (DC-DC converters thermal cycling), CMS (preparation for testing dosimetry in B-field), ATLAS ITK (heaters thermal cycling). Many other projects as for example CROME (CERN radiation monitoring electronic system, carried out by HSE-RP) asked the QART lab for support and technical advice.
71
All the 4 main LHC experiments had upgrade projects that used the QART lab facilities and advice, and considering the clients requirements an additional area of about 35m2 is under refurbishment for activities compatible to silicon sensors, front-end electronics and hybrids quality assurance and control.
1200 DC-DC converters in preparation for thermal cycling test.
Departmental Silicon Facility (DSF)
Petra Riedler
The common DSF clean area has been intensely used also in 2018. The ALICE ITS and MFT continued to produce modules for the upgrade of the detector during LS2 in a dedicated zone at the back area of the clean room. Furthermore, work has continued to increase on the CMS outer tracker module studies as well as on the ATLAS pixel module assembly work. Both activities are related to upgrades of the detectors foreseen during LS3. The electronic access as well as continuous efforts by all users have helped to improve the overall cleanliness of the area. In November 2018 a dedicated campaign has been carried out to measure the particle contamination in the various zones of the DSF common clean area. Other activities, e.g. pixel R&D, medipix, LHCb VELO upgrade have continued throughput the year in their dedicated areas in the common clean room. Also for 2019 this high level of activity of various projects will continue in the common clean room.
7.3. Thin Film and Glass Lab Thomas Schneider
Based on more than 30 years’ experience and R&D, the TFG lab in EP-DT gives dedicated support to the different CERN experiments and groups in terms of thin film coating. Highly specialized technical solutions have been developed for the different HEP detector applications, as there are UV enhanced spectral reflectors, photomultiplier Wave Length Shifting (WLS) coatings, photocathode (PC) coatings and lateral plastic fibre coatings. The attached glass and ceramic workshop is another unique facility at CERN for the machining of hard and brittle material (glass, Pyrex, quartz, sapphire, ferrites and other ceramics) with high precision. Using special diamond
72
tools, several prototypes and small series have been produced in 2018 for Isolde, EN-VSC and the µ-channel cooling activities in EP-DT. A major effort in 2018 has been the replacement of 2 generic mid-size coaters (from the 60’s) with a new “state of the art” Box-Coater. Delivered end of the year it will be commissioned and brought to service early 2019. The new device will further ease and improve the quality of the future coatings in the lab.
New box coater installation in TFG Inside view of box coater
On top of this mid-size generic coater, there are four more custom build ones for dedicated exotic use (WLS and PC) and one bigger installation for substrates up to 1m diameter. Common for all these installations is the Physical Vapour Deposition (PVD) thermal evaporation process. With this technology, all kinds of materials (metals, dielectrics and even organic material) can be deposited on a multitude of substrates. Main focus for thin film coatings in 2018 has been:
Extensive coating campaign for the Picosecond R&D test beam activities of RD51
Test coatings to prepare the LHCb RICH1 upgrade program planned for 2019
Zinc coatings for medical application of MEDICIS and a
Follow up production of scintillating fibre based beam monitors units.
Lateral coating of scintillating fibers Installation of beam monitor unit in H2
73
The beam monitor project, in collaboration with BE-BI, included lateral coating of the scintillating fibres as well as the manufacturing of the in house developed (R&D in 2017) detector units. Eleven units have been produced to fully equip the H2 and H4 beamlines of the neutrino facility. To qualify the outcome of the coating products, the TFG optics quality control lab is equipped with several spectrometers and microscopes. Over the years, the CERN optics community has very well adopted this infrastructure. In addition to the thin film core activity, the TFG lab is strongly engaged to share its expertise and infrastructure with other CERN activities. In 2018, the assembly of seven NA62 GigaTracker detector units (see section 3.2.2) has been hosted in the TFG cleanroom. As the years before, three CERN apprentices (Physics Laboratory Technicians) have been trained in the glass and ceramics workshop for 3 months each.
7.4. Scintillator Lab and Workshop Sune Jakobsen and Raphael Dumps
The scintillator workshop has provided advice, repairs and production of scintillator counters for 15-20 projects at CERN in 2018. This includes ATLAS, ALICE, LHCb, CERN Beam Instrumentation, RD51, beamlines for schools and CosmicPi. As most project requests ~40 mm PhotoMultiplier Tubes, PMTs, a mini stock has been build up to eliminated the long delivery time. A new standard design has been made to connect the PMT to the light guide while having the possibility to add additional magnetic shielding and easily support the PMT/scintillator. The new design will first be used for the FASER experiment for triggering and vetoing.
Exploded view of a standard PMT
7.5. Composite Lab François Boyer
The composite workshop has reinforced in 2018 its capabilities in terms of applications, infrastructures and dedicated tools. A new freezer room with a use volume of 13.5m3 has been
Closure of the lab New freezer room
74
delivered and installed in the lab. This freezer room allows storing all the pre-preg materials and thermoset resins at -20°C. With the installation of new separations and a new roof, the EP-DT lab doubled in size reaching now 290m² dedicated to the composite activities. The composite lab is involved in several projects for the different experiments. In addition to this, contributions were also provided for the accelerator sector. The main projects are briefly detailed below: ATLAS After the production of the different truss (longeron) prototypes in 2017, the composite lab developed and produced new end parts in the frame of ITK program for ATLAS Pixel upgrade Phase II. The EP/DT Composite lab is also involved in the new design of inclined region for the outer barrel and begins with prototyping activities on carbon rings. The production of full prototypes is expected in 2019.
New carbon end part for ITK Truss longeron Prototype of a small segment of ITK carbon ring
CMS After the production of some TBPS ring prototypes in 2017, the composite lab continued his involvement in the upgrade of CMS Outer Tracker phase II by producing some TBPS beam prototypes. These beams will be used to integrate the different TBPS rings. In the meantime, the composite lab keeps producing and improving the surface’s quality of carbon plates used for 2S and PS modules. These plates need to have a flatness below 50µm.
TBPS Beam support Carbon plate for 2S and PS modules
75
LHC As support to the LHC magnet activities, the composite lab started a new development for a cold foot support. This new cold foot will support the first MQXFB 8.1m cold mass. The part was produced with triaxial GFRP prepreg (Glass Fibers Reinforced Polymer). Its weight is about 2kg and it is able to support 17t in compression. Among other activities, some insulators parts used in PS and SPS have also been manufactured. In fact, in the frame of LIU-PS project, some glass fibres/Polyimide sleeves were produced. These sleeves have a length of 1m and it consist of 4 layers of prepreg glass fibres/Polyimide. Some insulators shims have been also produced with the same material for MSE magnet located in the SPS.
Preform in GFRP of the cold foot Pyralin sleeve used as insulator for BSW42 LIU PS and insulator shim for support for dipole cryostat MSE-SPS spool
CLIC In the framework of AIDA calorimeter project, the composite lab produced 25 carbon-fibre envelopes. These supports have a total thickness below 750µm and are composed of 5+ 1 ply of prepreg woven. These envelopes will be used in FCAL beam tests in November 2019 at DESY Hamburg. They will host the silicon sensors and the readout electronics.
7.6. Micro Pattern Technologies Workshop Rui de Oliveira
Large GEM mass productions
The mass production of GEM detectors for CMS GE1/1 and the ALICE TPC project ended respectively in June and October 2018. More than 1300 GEMs have been produced during 24 months. The GEM size ranged from 0.5m x 0.7m to 1.4m x 0.5m (see next figure with the ALICE example). During the most productive period up to six technicians where assigned to the production of the GEMs, reaching a throughput of close to 70 GEMs of 1.4mx 0.5m per month. Despite the difficult conditions of production due to building 102 (lack of space and bad ergonomy), the yield of production has been constantly growing. The first production was showing less than 70% yield, while for the last batches yields of 100% have been reached a few times with an average of 90% during the last 6 months of production. After a volume reduction of the production in the fall of 2018 and in the beginning of 2019, a new mass production period, beginning in June 2019, will start for the second phase of the Muon detector upgrade of CMS GE2/1. The workshop is supposed to produce half of the required quantity for the full project, approximately 500 GEMs, split in two different sizes: 1.3m x 0.5m and
76
0.8m x 0.5m. The team in charge of this production is reduced compared to 2018. The reasons for this are the lower quantity of GEMs to be produced compared to the GE1/1 project and the longer allocated time for the production. Four technicians during 2 years should bring enough work force to complete this production. Concerning quality, several tests are performed before delivering the GEMs to the experiment: Holes diameter measurements, uniformity checks and leakage currents at high voltage checks in ambient air. The experiments are usually repeating these tests for cross checks, but they are also adding new ones: leakage current measurements in a controlled atmosphere, precise holes diameter mapping with automated scanners, X-ray scans. A GEM is accepted only after all these validations.
Machine installation program in building 107
The resettlement of the building 102 to the new building 107 ended beginning of May 2019. By March 2019 95% of the move was completed.
CNC Lab Plating Facility
Press Lab Test lab
CMS GE1/1 long GEM. Picture taken during the uniformity check on a back illuminated wall. This is one of the screening test done at the
production level before delivery.
ALICE GEM production. Three small
GEM fit in this format
77
Production activity started in building 107 in April 2018, the first area welcoming a real production was the lab dedicated to the CNC drilling and milling. At the same time we have installed the three long chemical lines in the plating facility. Two of the three lines are dedicated to Carbon treatment of PCB holes and chemical cleaning of holes respectively. The last one is used to create, in a controlled way, copper oxides on the panels. This last line is mandatory to prepare copper to get perfect gluing of multilayer structures. In the same room, baths for copper electro plating and hoods for Gold and NI/Gold plating were previously installed by the contractor team for building construction. All these wet equipments were finally working at the beginning of 2019.
In May 2018 we moved our two presses in the new building. The equipment is used to produce multilayer boards or flexes. In June 2018 all the equipment for PCB tests were moved: Automatic Optical inspection machine, flying probe tester and many microscopes/binoculars.
Photolithographic lab Etching room
Immediately after this, the photolithographic labs was moved. This step was the most complex due to the number of equipment (more than 10), their diversity (laser direct imaging, large ovens, laminators etc.) and the ultra-short period of one week allocated to do the move. All the activities in PCB manufacturing are naturally interlinked: if one is stopped it will affect others. One can maintain a minimum of activity. If the photolithographic lab is stopped, the full workshop production stops. In September 2018 all the copper etching machines, stripping machines and GEM baths were transferred to the etching room in 107. Part of the GEM production at that time was done in the clean rooms of 107 and 102. At that point, close to 90% of the activity was transferred; nobody was anymore permanently working in 102 (out of punctual activities in the Clean room). It then took us nearly 5 months to stabilize the activity in the new building before starting the last chapter of the move: the clean room transfer. This step started beginning of March 2019 and is still ongoing, the large equipment are already in 107. We are now waiting for the final commissioning of the new clean room to bring all the small equipment (ovens, spinner, UV lamps etc.). The completion is expected beginning of May 2019. Building 102 is now free from any activity involving chemicals. According to ongoing discussions it will be dismantled in 2019.
Aluminium bus production for the ALICE inner tracker
The Aluminium Bus circuit production for the ALICE barrel inner tracker is now ending in the MPT workshop. The last circuits will be delivered spring 2019. We have produced in the MPT workshop more than 100 busses (see the following Fig.). This bus is a double sided aluminium cladded Kapton.
The Aluminium is deposited by vacuum magnetron DC sputtering with a thickness of 30m on both sides. This thickness is quite unusual and challenging for this deposition technique. The production foil size of 95cm x 30cm, including many individual busses, is also something far from any standards in this field. The signal strips are obtain by conventional photolithographic steps, the aluminium etching chemistries have been specifically developed at CERN to cope with these thick layers.
78
After quality inspection, the flexes are populated with the decoupling capacitors. The pixel detector chips are then glued on the back of the flex. This gluing is selective; the areas of the chip seen through the oblong hole in the bus are not covered with glue. Through this hole the electrical connection is made by conventional aluminium wedge wire bonding. After extensive performance test to check that the staves are fine, they are finally assembled in a barrel structure on carbon fibre fixtures. There are still many flexes to be produced, a few hundred of smaller busses for the MFT part of ALICE are still missing. In addition, prototypes are being built for new TPC inner tracker projects copying the ALICE design philosophy. To our knowledge there are today only two workshops in the world doing such low mass circuits, one in Ukraine and one at CERN. The production techniques are quite different (tab bonding versus vacuum deposited aluminium) each technique can do things that the other one cannot. At the end both are used in the ALICE project for their respective advantages.
8. Safety in EP-DT Burkhard Schmidt for the team in charge of safety in DT
During 2018 the group has further consolidated the conformity of the park of machines and tools, attaining full conformity for all of them (~170 in total) in the different DT workshops. To manage, trace and record the operation of machines and special equipment in the EP-DT workshops in buildings 108, 162 and 166, which are also used by colleagues external to DT, an automatic system called TRAKA is in place. Each workshop is led by a Workshop Supervisor. For the Micro Pattern Technologies workshop, which moved in 2018 from building 102 to 107, about 80% conformity has been reached for the machines. Several hundreds of safety documents and procedures have been stored in the new EDMS safety structure for DT group. New additional safety measures were taken to follow-up safety aspects in the MPT workshop. Support was provided to the technical responsible in the framework of the supply and for all purchasing and logistics aspects. A review process for DT safety has started with special emphasis on lab conformity. This is done in close collaboration with the DSO and her team and is planned to progress further in the course of 2019.
Left: Single bus (in green), it is sitting on its assembly fixture. Right: Magnified view of the Aluminum Bon-ding wires making the connection between the flex and the pixel detector chip sitting underneath the Bus.
79
9. Secretariat V.Wedlake
In 2018 the DT secretariat continued to provide administrative and secretarial support to the group and to the following experimental collaborations: NA62, RD50, RD51, CLOUD, MoEDAL and FASER.
Veronique Wedlake in the EP-DT secretariat, 166/R-01
10. Selected Publications and Contributions to Conferences
1. Ch. Joram, C, Gargiulo, E. Oliveri, A. Onnela, P. Riedler, B. Schmidt et al., Strategic R&D Programme on Technologies for Future Experiments, CERN-OPEN-2018-006, https://cds.cern.ch/record/2649646/files/CERN-OPEN-2018-006.pdf
2. Michael Moll, Displacement Damage in Silicon Detectors for High Energy Physics IEEE Transactions on Nuclear Science, Vol.65, No.8, August 2018, 1561-1582 https://doi.org/10.1109/TNS.2018.2819506
3. M. Centis Vignali, R. Dalal, M. Gallinaro, B. Harrop, G. Jain, C. Lu, M. McClish, K. T. McDonald, M. Moll, F. M. Newcomer, S. Otero Ugobono, S. White, Characterization of Irradiated APDs for Picosecond Time Measurements; 2018 JINST 13 C01041; https://doi.org/10.1088/1748-0221/13/01/C01041
4. Sofıa Otero Ugobono, Mar Carulla, Matteo Centis Vignali, Marcos Fernandez Garcıa, Christian Gallrapp, Salvador Hidalgo Villena, Isidre Mateu, Michael Moll, Giulio Pellegrini and Ivan Vila; Radiation Tolerance of Proton-Irradiated LGADs; IEEE Transactions on Nuclear Science, Vol.65, No.8, August 2018, 1667-1675; https://doi.org/10.1109/TNS.2018.2826725
80
5. J. Bronuzzi, M. Moll, D. Bouvet, A. Mapelli and J.M. Sallese; Principle of the Electrically Induced Transient Current Technique; 2018 JINST 13 P05021 https://doi.org/10.1088/1748-0221/13/05/P05021
6. Leonid Makarenko, Stanislav B Lastovskii, Hanna S. Yakushevich, Michael Moll, Ioana Pintilie Effect of electron injection on defect reactions in irradiated silicon containing boron, carbon and oxygen; Journal of Appl. Physics 123, 161576 (2018)https://doi.org/10.1063/1.5010965
7. E.Gaubas, T.Ceponis, L.Deveikis, D.Meskauskaite, J.Pavlov, V.Rumbauskas, J.Vaitkus, M.Moll, F.Ravotti; Anneal induced transformations of defects in hadron irradiated Si wafers and Schottky diodes; Materials Science in Semiconductor Processing, Volume 75, 2018, 157-165; https://doi.org/10.1016/j.mssp.2017.11.035
8. L. F. Makarenko, S. B. Lastovskii, E. Gaubas, J. Pavlov, M. Moll, H. S. Yakushevich, L. I. Murin; Injection Annealing of the Self Di-Interstitial – Oxygen Complex in p-type Silicon, Proceedings of the National Academy of Sciences of Belarus, Рhysics and Mathematics series, 2018, vol. 54, no. 2, рр. 220–228; https://doi.org/10.29235/1561-2430-2018-54-2-220-228
9. Sofía Otero Ugobono, M. Centis Vignali, M. Fernández García, C. Gallrapp, S. Hidalgo Villena,
I. Mateu, M. Moll, G. Pellegrini, A. Ventura Barroso, I. Vila, Multiplication onset and electric field properties of proton irradiated LGADs; PoS (Vertex 2017) 041; https://doi.org/10.22323/1.309.0041
10. K. Moustakas et al., Development in a Novel CMOS Process for Depleted Monolithic Active
Pixel Sensors, IEEE Nuclear Science Symposium, Atlanta, USA, 2017,
http://dx.doi.org/10.1109/NSSMIC.2017.8533114
11. R. Cardella et al., LAPA, a 5 Gb/s modular pseudo-LVDS driver in 180 nm CMOS with capa-
citively coupled pre-emphasis, PoS TWEPP-17 (2017) 038, https://pos.sissa.it/313/038/pdf
12. W. Snoeys et al., A process modification for CMOS monolithic active pixel sensors for
enhanced depletion, timing performance and radiation tolerance, Nuclear Instruments and
Methods A 871 (2017) 90-96 https://doi.org/10.1016/j.nima.2017.07.046
13. I. Berdalovic et al., Monolithic pixel development in TowerJazz 180 nm CMOS for the outer
pixel layers in the ATLAS experiment, 2018 JINST 13 (C01023)
https://iopscience.iop.org/article/10.1088/1748-0221/13/01/C01023
14. G. Quero, G. Gorine, F. Ravotti, et al., A novel Lab-on-Fiber Radiation Dosimeter for Ultra-high
Dose Monitoring, Nature Scientific Reports, vol. 8, article 17841 (2018)
https://www.nature.com/articles/s41598-018-35581-3
15. Federico Ravotti, Dosimetry Techniques and Radiation Test Facilities for Total Ionizing Dose
Testing, IEEE Transactions on Nuclear Science, vol. 65, no. 8, pp. 1440-1464, Aug. 2018,
https://ieeexplore.ieee.org/document/8347010
16. G. Gorine, G. Pezzullo, M. Moll, M. Capeans, F. Ravotti et al., Metal Thin-Film Dosimetry Tech-
nology for the Ultra-High Particle Fluence Environment of the Future Circular Collider at CERN,
Radiation and Applications, vol. 3 (3) pp. 172–177, 2018. doi: 10.21175/RadJ.2018.03.029.
81
17. G. Gorine, F. Ravotti, J. M. Sallese, Future Circular Collider Study, Volume 3: The Hadron
Collider (FCC-hh) Conceptual Design Report, pp. 93-94, 2018. Submitted for publication to
Eur. Phys. J. ST. https://cds.cern.ch/record/2651300.
18. Konul Gurbanli, Development of a new PS IRRAD Facility website,
September 9, 2018, CERN-STUDENTS-Note-2018-110.
19. Jose Cabrero Holgueras, Development of a Readout System for RadMON Sensors on Arduino
YUN microcontroller, October 8, 2018, CERN-STUDENTS-Note-2019-006.
20. Eva Sicking, Steffen Doebert, Towards TeV-scale electron-positron collisions: the Compact
Linear Collider (CLIC), Europhysics News, Volume 49, Number 1, January-February 2018,
https://doi.org/10.1051/epn/2018102
21. N. Akchurin et al., First beam tests of prototype silicon modules for the CMS High Granularity
Endcap Calorimeter, published in JINST 13 (2018) no.10, P10023,
https://iopscience.iop.org/article/10.1088/1748-0221/13/10/P10023/meta
22. The Compact Linear Collider (CLIC) - 2018 Summary Report, CLICdp and CLIC Collaborations,
2018, https://e-publishing.cern.ch/index.php/CYRM/issue/view/66
23. A. Robson, P.N. Burrows, N. Catalan Lasheras, L. Linssen, M. Petric, D. Schulte, E. Sicking,
S. Stapnes, W. Wuensch, The Compact Linear e+e− Collider (CLIC): Accelerator and Detector,
Input to the European Particle Physics Strategy Update on behalf of the CLIC and CLICdp
Collaborations, 2018, https://arxiv.org/abs/1812.07987
24. R. Sipos, The DAQ for the Single Phase DUNE Prototype at CERN IEEE Transactions on Nuclear Science, DOI: 10.1109/TNS.2019.2906411 https://ieeexplore.ieee.org/document/8672182
25. E. Gamberini, G. Lehmann Miotto, R. Sipos, et al., FELIX based readout of the Single-Phase ProtoDUNE detector, IEEE Transactions on Nuclear Science, DOI: 10.1109/TNS.2019.2904660 https://ieeexplore.ieee.org/document/8668437
Selected conference talks:
1. CERN academic training lecture on “Detector technologies for CLIC”, Eva Sicking
https://indico.cern.ch/event/668148/
2. Talk on “The CLIC detector” presented at the International Conference of High Energy
Physics (ICHEP) 2018 in Seoul, South Korea, Eva Sicking, https://www.ichep2018.org/
3. Talk on “The ProtoDUNE Single Phase Detector Control System”, M.J. Rodriguez et al.,
CHEP 2018, Sofia, Bulgaria, https://indico.cern.ch/event/587955/contributions/2935760/
82
Editors, P.Martinengo and B. Schmidt for EP-DT ©CERN, June 2019
Reflective Mylar foil glued to the NA62 Cone disc PH-DT TFG Lab