13.4.02, v.korbel, desy ii. ecfa-desy lc workshop, st.malo 1 status of the tile-hcal for the...

13.4.02, V.Korbel, DESY

II. ECFA-DESY LC workshop, St.Malo

1

Status of the Tile-HCAL for the Detector at TESLA

Status of the Tile-HCAL for the Detector at TESLA

1. Actual project time planning2. Groups involved3. The milestones to the next PRC meeting3. Actual R&D

-- DESY-LPI-- DESY-H1-- The minical array

4. E-flow studies-- The calorimeter prototype-- Testbeam at DESY-- Testbeams CERN, ...?-- Collaboration with other groups



2

Groups involved:•DESY-LPI,

tile-WLS fibre optimisation,Photodetectors, simulationDESY FLC activityE.Devitsin, V,K., V.Kozlov, L.Popov, S.Potashov, A.TerkulovV. Morgunov, simulation and

reconstruction strategies •DESY-H1,

Photodet, preamps, ADC-RO, calibration, prototype simulationV.Andreev, A. Fomenko, V.K., S.Reiche, P.Smirnov, Y.Soloviev

•ITEP, Moscowsee presentation today

•MEPHI, Moscowsee presentation today

•Prague, Univ. and Academy of Sciencesee presentation today

•Imperial College London and Birmingham

ADC-RO,together with ECALP. Daunkey et al.

Project time planing in 2002-2004:

•R&D in 2002:• tile-fibre optimisation• signal RO

photodetectorspreamplifiers and shapers ADC’s, FADC’’sbuffering and DAQ

• studies with a ‘minical’ test array• technical design studies:

optimise the 1m3 prototype for HCALupgrade the TDR calorimeter design

• simulation studies to optimise the calorimeter structure

• PRC meeting in November 2002• 2003, prototype construction envisaged• 2004, prototype beam tests

and data collection• than presentation of realistic E-flow reconstruction



3

The milestones

The R&D program as reaction on demands of PRC: agreed task list from 11.11.2001, DESY

1. Period: 11.-12.2001-----------milestone: start minical test-array set up and - test operation at DESY, few channels

2. Period: 1.-2.2002-----------milestone: LED stability monitoring, stable photo-detector operation possible,-----------milestone: start cosmic test with minical, with increasing number of active tiles,-----------milestone: finish construction design of 1m3-prototype (ITEP, Prague, DESY)

3.Period: 3.-4.2002-----------milestone: optimal HCAL cell sizes defined from simulation (DESY),-----------milestone: final results from homogeneity TF-system measurements and simulation (Prague, ITEP), scintillator, WLS, reflector, clear RO fibres fixed.



4

The milestones,2

4. Period: 5.-6.2002-----------milestone: TF radiation hardness and ageing studies completed (Tashkent)-----------milestone: definition of final TF-RO plate geometry and RO fibre routing (ITEP)-----------milestone: operation of appropriate final Silicon Pixel PM's with preamps (MEPHI)-----------milestone: operation of all 64 PD's (CAMAC-RO) in minical (ITEP, DESY)

5. Period: 7.-8.2002-----------milestone: build a prototype of multiplexing +ADC RO (similar to ECAL) (DESY, LPI, ITEP, IC, U-BIR)-----------milestone: minical beam-tests at DESY, 1-6 GeV e-test beam

6. Period: 9.-10.2002

-----------milestone: build a prototype of Mplx +ADC RO, (DESY, LPI, ITEP, IC, U-BIR)-----------milestone: run a complete minical, 64 channels with appropriate PD's and RO as envisaged for 1m3 PT (ITEP and DESY), MEPHI-----------milestone: beam tests with electrons, test: energy resolution, noise, linearity,..... (all institutes)-----------milestone: test minical in a 1.2 (4 T) magnetic field, needs inquiry



5

R&D studies on the tile-WLS fibre system at DESY and LPI/Moscow

Green WLS fibre:attenuation length

Scintillatorlight yield

Scintillator :uniformity of RO

Reflector foil:mirror or diffraction, light yield Reflector foil:

uniformity of RO

Tile-WLS system:• optimal coupling,• light yield,• uniformity>>>> 5x5 cm2, than: ...7x7....16x16cm2

tiles

Scintillator :~6600 m2, costs!

clear RO fibre:attenuation length

R&D

WLS fibre:bending in small radius

WLS fibre:ageing, rad. hardness

WLS fibre:fibre end mirroring

R&D by:DESY-H1-LPI ,ITEP, Moscow, Prague

R&D by:DESY-H1-LPI ,ITEP, Moscow, Prague



6

Find optimal WLS fibre

Optimal WLS:-short abs. length for scintillation light-long atten. length of WLS shifted light



7

Tile-reflector studies

So far studies with•aluminised mylar•white teflon foil•Tyvek paper (Papierunion)best results with Tyvek----several layers needed----optimisation under way

>>>tests with super-reflector (95-99%, 380 nm) 3M special, “3M Radiant Mirror Film”20% more light collected!!!!



8

Scintillator/WLS fibre coupling

Fibre end polished, openTyvek coating of tile,air gap contact tile/WLS

Look for cheaper scintillator from Russia, with similar performance!

sensitive PM,number of photoelectrons

from Gaussian fit to all individual N ph.e.contributions(poisson distrib.)



9

original fibre RO conceptas described in the TESLA-TDR.

Original concept of tile plate read out

1. layer

Problematic are the small scintillator tile sizes to be read outStudy other possibilities



10

Search for optimal WLS-Fibre arrangement

10 different TF configurations studied• WLS fibre end polished, no reflector• air gap contact to tile• Tyvek reflector on tile

tile irradiated withcollimated Ru106 source,simple current measurement for LY

Ru106 source, ~ 2cm



11

Uniformity scan for optimal WLS-Fibre couplings

10 configurations studied:

best LY:diagonal 1/4 c fibre,RO in groovebest uniformity:straight fibre,RO outside tile

All tiles: 5x5x0.5 cm3

source =1.95 mm,



12

Best coupling shape for WLS fibres?

Loops ph.e./tile ph./cell•1 7.7 184•2 10.5 256•3 10.0 240unbent fibres:along edge, no groove: 7.0 168along groove in centre 7.7 184diagonal fibre, groove: 10.5 256diagonal, minimal bend: 11.0 264Other criteria to use unbent fibres:

•easy to insert,•less risk of damage •no bending stress,•> less ageing



13

Inside magnetic field:•HPD’s, expensive•Silicon photodiodes, low gain, noise, n.c.effects•APD’s, to study•Si-photomultipliers (Si-PM), see MEPHI presentationOutside field:•single small photomultipliers, logistic problem,•Multi-anode photomultipliers (MA-PMT’s)Some details: ---APD’s:

gain of 100-500 possible, extended noise? temperature stability, gain shift of 1-2% /°C low capacities 10-15 pF possible, >> lower amplifier noise tight packing in detector requires small sizes Hamamatsu: >> 4x8 channel Si-APD array, S8550, study started in Prague, 2 x 2 mm2 photo-cathode pixels, specimen >>> common bias voltage, <500 V, gain 100-500 (?), peak~600nm, >> work on integration with monolithic preamps, in collaboration with

•MPI Munich, Eckart Lorenz•ITEP, Y. Guilitski•Brookhaven, G. Woody

Photodetectors

~1 x 2 cm2



14

---Si-PM’s: Studies at MEPHI (Moscow), B. Dolgoshein, See talk at International Conference on “Advanced Technology and Particle Physics”, Como, Italy, Oct. 2001 100-4000 pixels/mm2 with common output, pixel size is 15-50 m, Cpixel ~100 fmF each pixel consists of:

--drift region in inner electrical field (10-500 V/cm)--Geiger region, ~0.7 m, electrical field of 500.000 V/cm gain 0.2..20*105 >>--output signal is proportional to number of pixels fired:

S ~Npixel fired = m*(1-e-Nph*/m) with:•M - total number of pixels,•Nph - number of photons,• - photon detection efficiency.

--sensitive to single photons,--problem is dark carrier rate (-40°C, ~200 kHz) >>--first selected samples available Nov. 2002,

---photomultipliers,properties known, have to be small, compact and cheap!

Photodetectors



15

---multi-anode photomultipliers (MA-PMT’s) >>> Hamamatsu, “Metal Channel Dynodes”,

types:R5900-M16 >> H6568, 4x4 channels (4x4 mm2 each) orR5900-M16 >> H7546, 8x8 channels (2x2 mm2 each) New versions with less cross talk,at DESY enough available to equip fully the ‘minical’, 64 channels

disadvantage: sensitive to small magn. field variations, dynamic range of MA-PMT’s is only a few times 102, sensitive to fields > ~100 G, light transport in ~7 m clear RO-fibres outside 4T field, att~ 10 m >> 50% amplitude loss,gain uniformity between anodes: typ. 1.3 cross talk in MA-PMT’s (~ 1-2%),

advantage: easy access, temp. stability, small noise, gain > 106

>>>>> will be used for minical test array studies as first option

Photodetectors



16

The dynamic range of light signals:

From V.Morgunov

needs to be referred to events

MIP in 3 layer cell deposes ~70 MeV

maximal energy deposit ~ 15 GeV

If MIP counted in channel 10 >>> 14.4 GeV >> channel

2048, >>> dynamic signal range:

11 bit12 bit ADC’s would be excellent

overflow problem to study: 1. correction methods using

neighboured cells,2. non linear ADCs



17

Calibration and monitoring

of photodetectorsCell calibration with MIP’s !

~250 000 cells, many calibration events neededoff-line:

•some days during shut downonline:

•between bunch trains, cosmic muon ~95% efficiency,

useful ~2*10-2 Hz, >> 1728 events/day/cell >> 2.4% calibration precision in one calibration day!

•in bunches (halo muons, endcaps only)

10 halos/BC, >> 1.1*10-4/sec/cell14100 BC/sec , > 1.6 Hz/cell>> few minutes calibration time needed

Light from Scintillator

pulsed LED

APD

Light mixer

Stable photodiode

readout

readout

monitoring gain of PD’s:•method A:

pulsed LED,light split and send to all photodetectors, a stable photodiode, +/-1°C, dG/G < 1%o monitors LED gain via signal peak position

•method B: pulsed LED,stable gain from gaussian of PM signal



18

The layer structure of the HCAL

sandwich layers, lamination in: 38 in barrel, 45 in end caps, add. 4 in pole tips of end-capswith scintillator tiles: ~ 800 000 tiles

sizes: ~5x5......~16x16 cm2

cells: ~ 160 000 cells• 9 (10) cell layers in barrel (end cap),• grouped from 3,3,3,4,4,4,5,5,7

(3,3,3,4,4,4,5,5,7,7) s/w layerscell volumes:

• (0.22)2 x0.36(0.71)2 x0.84• (1.6 RMoliere)2 x 3.5 X0 ...(5 RMoliere)2 x 8 X0

such a detailed structure to be studied in prototype

HCAL granularity to be optimised• for E-Flow reconstruction of jet energies,• ~angles• and jet-jet masses.



19

[

1

[

[

[

[

Assembled with up to27 scintillator layers:165 scintillator tiles of: 5x5 cm2 >> 45 cells 10x10 cm2 >> 8 cells 20x20 cm2 >> 2 cells

read out by WLS fibres to photo-detectors:•16 small PM’s•3x16 MA-PM’s,•1x32 APD arraylater:•Si-PM’s (MEPHI, Moscow)

Tile and S/w structure

Cell structureTrack cambers?

A small pre-prototype : the „minical“-array

Aim of this device is study of:stability, ageing and calibration with MIP’s



20

Beam tests with the „minical“-array

Beam at DESY, “Strahl 22”reserved for •2 weeks in July, set up, cosmics•2 weeks in August, 1-6 GeV e-•later in this year:test measurements in/between (?) solenoids>>> APD’s or Si-PM’s as photodetectors needed!



21

HCAL prototype for E-flow studies

Required volume ~ 1 m3

~ 800-1200 calorimeter cellsFe-structure can accept•analogue •or digital HCAL

10 GeV pions

100 GeV pions

100 cm

Leakagedetector needed!



22

Studies with the prototype

beam tests:--1m3 structure made from Fe(ss) (or Brass?)--stack should be used for tile and digital HCAL studies--need electron, pion and proton test beam, muons for fast calibr?--different energies between 1-30 GeVperformance studies: --linearity, --energy calibration and energy resolution,--position resolution, --measure containment of showers, leakage (sides and back) >--software compensation (e/responseimprovementsimulation tests and reconstruction studies:--verify shower shapes from MC simulation, tune MC --energy flow studies, establishment of real performance:--overlay of individual measured beam particles to jets >>--with entrance coordinates and angles as indicated from MC--include cell size and nonuniformity, calibration precision, noise...>>>> reconstruct objects as Z, W, top, Higgs in these studies collaboration with interested US groups agreed



23

Some first simulation results, reconstruction a la H1

V.Andreev •pions in the 1m3 ss-prototype,•resolution ~ 0.395/E

•considerable leakage deteriorates this resolution•tail catcher needed:

• with 0.8 dead Al coil• and realistic Fe structure

•1 cm2 cell structure,•RO of each layer >>>> 38 x 104 cells

/E ~ 0.395/E

mean leakage/incoming pion



24

Realistic event representation

Strong bending in the magnetic field of 4T

charged particle showers are not vtx pointing

t-tbar production, 800 GeV, several W jets



25

Outcome of the meeting (27.3.02, Caltech, Pasadena, 19:30-21) , page 1 R. Frey, V. Korbel, S. Macgill, V. Morgunov, D. Strom, H. Videau, V.Zutshi agreement on closer future co-operation in calorimeter studies:

1. Invitation to the regular E- and HCAL meetings, especially members from ANL/ZEUS. Connection via Video-Conference, thus meetings will start at 14:00 MEZ. The next monthly HCAL meeting at DESY is scheduled for 6.6.2002.2. We keep CALICE web page up to date with E- and HCAL meetings, pointers also to minutes and interesting transparencies of weekly DESY internal HCAL meetings.3. Information on schedule for minical studies at the DESY test beam. First 2 weeks in July are planned for set-up of minical in test beam. Detailed studies are foreseen in the 2 last weeks of August for MIPs and electrons (1-6 GeV).4. V.K. will contact Michael Hauschildt, the test beam co-ordinator at CERN and try to get information on availability of beams (1-30 GEV, hadrons, muons and electrons) in 2004, CERN PS.5. For other alternative test beams we have to look for at Serpuchov, Brookhaven,….?6. Discussions on specification of 1m3 HCAL prototype (absorber material, dimensions, tile sizes, equipped volume,..) and side leakage tagging and tail catcher requirements are under way. To optimise the prototype, simulation and reconstruction studies have started at DESY by the DESY-H1-PPI group. The US groups declared strong interest to contribute to such studies.7. The Fe(ss)-HCAL stack is also foreseen for equipment with digital RO planes.8. Study of the required tail catcher, structure and effective volume to fill (tile plates / digital planes).



26

Outcome of the meeting (27.3.02, Caltech, Pasadena, 19:30-21) , page 29. Actual useable photodetectors, FE and RO electronics, all options have to be investigated for the prototype. A group of Imperial College, London has expressed strong interest to help with the design and implementation of the RO, starting from the ADC’s. So far DESY, ITEP, MEPHI, Prague are involved.10. The beam test results will be used as input to - Shower size and energy resolution measurements for individual particles, - Leaking energy measurements, the improvement in resolution and reduction of missing energy tails, - Tune the software compensation a la H1 to improve further the energy measurement, - Realistic energy-flow studies with overlay and reconstruction of single particle clusters according to e.g. simulated W, Z, Higgs, t-tbar production.......11. The effects of the magnetic field which changes significantly the charged track vectors in front of the calorimeter can be taken into account in a “realistic” energy flow simulation and reconstruction using measured prototype showers overlaid according to the simulated events in a cockeyed, non vertex pointing manner.12. Aim is to find from such simulation and reconstruction studies all required beam test settings as: - Particle types and -energies, - Particle impact angles needed for overlays to jets and final states, - Number of particles to collect /data set. With these studies the useful prototype dimension, cell sizes and required volume fill (~4000 tiles combined to ~1000 electronic RO channels) and TC structure have to be optimised. Also we have to find out, which volume to fill with digital planes to draw a conclusive comparison.Probably, if 40 layers of digital RO will not be available at time for alternative test, as many tile layers as possible can be replaced with digital layers and consecutively shifted along the prototype depth. This can be studied in detail also!



27

Summary

•CDR >> TDR (2001) considerable improvement in concept•straight fibre RO, at least for small cells, instead loops, >> ~25 ph.e. for calibration with PM for MIPs (~250 photons)•further work on further improvement in light yield,•lateral cell response uniformity seems ok (+/- 3-4%), •but needs confirmation by simulation studies•studies are underway for cell size optimisation

•s/w compensation (~ size of elm. cluster)•E-flow measurement•economy, costs

•minical-prototype is in operation, more channels soon•prototype tests at CERN envisaged for 2004•wait for results from software prototype study group•how to implement realistic tail catcher?



28

Outlook

Approved, final concept2005 ?

Approved, final concept2005 ?

Here we are2002

Here we are2002

Detector ready forfirst e-e interactions:

2012 ?

Detector ready forfirst e-e interactions:

2012 ?

Concept,design studies,R&D,prototype to be builtfor 2004

Minical

design

13.4.02, v.korbel, desy ii. ecfa-desy lc workshop, st.malo 1 status of the tile-hcal for the...

Documents

simulation desy

ecal desy

prototype itep

minical itep

test minical

ecfadesy lc workshop

minical testarray

1m3 prototype