ecal review 5 th ild workshop @ lal orsay 23-25 may 2011 k. kawagoe kobe-u kyushu-u in april 2011

ECAL review5th ILD workshop @ LAL Orsay

23-25 May 2011K. Kawagoe

Kobe-U Kyushu-Uin April 2011

The ILD ECAL• Finely granular PFA calorimeter with tungsten absorber• Cell-size in baseline design ~ 5 x 5 mm2, num. of cells ~100M in total• Necessary to achieve less dead space, low production cost

Candidate technologies :• Silicon-tungsten• Scintillator-tungsten• MAPS/DECAL

Jet Energy Resolutionby M. Thomson

Barrel: 5 octogonal wheelsRmin = 1808 mm; Rmax = 2220 mmWidth = 940 mmEnd-caps: 4 quarters∅min = 800 mm

S. Uozumi@ILDWS2010

11/05/23 ECAL review K. Kawagoe 2

R&D studies of ILD ECAL are carried out inside CALICE Collaboration

For details of recent works, see slides at CALICE Collaboration Meeting last week at CERN.

Silicon tungsten ECAL status – progress towards DBD

“Physics prototype” 10k channel physics prototype

6 years of successful operation at DESY, CERN, FNAL

Validated principle and performance

Very few signs of agingCalibrations stable with timeNo problems with e.g. conductive glue dotsConnectors can get flaky with repeated re-connections

D. Jeans

Integration of ECAL into ILD-like detector

addressed within Technological Prototype development

Mechanical

~2/3 ILD barrel moduleunder construction

mould 1 alveolus

mould 3 alveoli

Core

2.5m long alveolae (endcap)

Fastening system

D. Jeans

Silicon sensors

Starting discussions directly with Hamamatsu engineers

investigate sensor improvements (laser cutting -> reduced edge areas)cost control

widen technical requirements(manufacturer chooses thickness...)

relax quality requirements(allow few dead pixels, higher leakage current...)

Batch of test sensors expected in a couple of months

D. Jeans

Front-end electronics

SKIROC2 ASIC produceddesigned for ECAL Si PIN diode readoutLow power, power-pulse capability

being tested

Front end PCB

Supports Si sensors and ASICs,Routes data to and from ASICs to outside world

Strict requirements on thicknessnow met by manufacturersSome improvements required

(planarity)

D. Jeans

Assembly of sensitive detectorsSensor -> PCB

gluing

ASIC -> PCBWire bonding

HV connectionKapton cables

Industrial techniquese.g. Anisotropic Conductive Films

Powering, cooling, DAQ

Compact, scalable systems under development

D. Jeans

Mokka ECAL simulation

Good level of realism

- dead area at sensor edge

- mechanical tolerance between sensors

- structural supports within modules

- support structure between ECAL and HCAL

- ECAL cables and cooling pipes

D. Jeans

SummarySilicon tungsten ECAL

Established designwell developed ideas about detector integration

No technical show-stoppers to current design- of course some challenges

As always, sensor cost is main concernstudies to better understand are continuing

in close contact with industry

D. Jeans

Scintillator-tungsten ECAL• Cost-effective scintillator strip calorimeter

aiming to have virtual cells by x-y strips crossing.

• Beam tests of the physics prototype have been performed to prove feasibility.– DESY 2007 (small prototype)– FNAL 2008, 2009 (test with AHCAL)

• ILD structure – Scintillator strips with 5 mm width 2 mm thick without WLS fiber– 3 mm tungsten, ~21 X0 in total

• Study of “strip-clustering” underway with realistic simulation• Remaining Hardware R&D issues :

– Study of 5 mm width scintillator-strip without WLS fiber– Dynamic range of photo-sensor– Establish design of the photo-sensor gain

calibration system

Scintillator strip (4.5 x 1 x 0.3 cm)

MPPCWLSfiber

18 c

m

18 cm

72 strips

x 30 layers

S. Uozumi@ILDWS2010


Strip-splitting method developed by Katsu has shown good performance.

Two scintillator layers are being constructed to be tested in the same mechanical structure as the SiECAL Technological prototype.

MPPC with more pixels (smaller pixel size) are being developed.

Strip-splitting method• An algorithm developed by

Katsu to split energy deposit in a strip to virtual square cells using information of adjacent orthogonal layers.

• After Mark’s tuning of PandraPFA for ScECAL, good jet energy resolution was achieved, although still a little worse than SiECAL.

• The origin of the difference between SiECAL and ScECAL to be further investigated.


w/o strip-splitting

with strip-splitting

SiECAL Mokka (5mmx5mm)

ILD with PandraPFAStrip width: 5mm

ScECAL to the technological prototypeIntegration of electronics

• Original idea for ILD– Two scintillator layers of orthogonal

directions in a drawer• The technological prototype

– The mechanical structure is designed for Si-pad layers: required thickness is different

– A few scintillator layers are being constructed, but only one layer in each drawer

– How to fix the strips in the structure ? Some ideas exist, to be further investigated.

• Test beam in 2012

electronics

stripscintillator


Flexible Printed Cable• MPPC has to stand up on the EBU• need a thin flexible connection : FPC

FPC+MPPC

EBU withSPIROC(DESY)

Surface-mount MPPC FPC


R&D of 5mm width scintillator strips• Direct readout of 5mm width scintillator strips to realize an

effective cell size of 5mmx5mm• Number of P.E. is roughly 14, good enough.• Aiming at good uniformity with small dead region


scintillator strip scintillator strip

acrylic spacer 3mmMPPC 25m pitch (1600 pixels)

14

5mm strip • improve homogeneity around the MPPC

hole hole filled with grease


LED-like package for MPPC ?

MPPC evolution

• Smaller pixel size (more pixels/mm2)– for better dynamic range and linearity– trade off geometrical acceptance for

photons

• 1600 pixel/mm2 : 25m pitch– ~36%eff, ~14 p.e. for MIP

• 2500 pixel/mm2 : 20m pitch– ~25% g.e., ~10 p.e. for MIP ?

• 4400 pixel/mm2 : 15m pitch– 35% g.e., ~14% for MIP ?

16

25m pitch


20m pitch

15m pitch

MPPC bench test• compare response curves by a LED

PMT

MPPCLED(pulse width ~ 5ns)

PMT responseADC

MPPC res.(p.e.)


Possible Idea for baseline design of the ILD ECAL• A lot of discussion has been done to form the “Unified ILD ECAL” in this month.

• One possible idea is a “hybrid-type ECAL” with silicon pads and Scintillator-strips.

– The silicon pads in pre-shower and shower-max region– The scintillator layers cover after the shower maximum– Another idea : Si layers interleaved in scintillator layers– Cost-effective– No two-fold ambiguity for the strip clustering with silicon sensors– Can use established the silicon and Scintillator ECAL technologies.– Need extensive simulation study to determine configuration of Silicon / Scintillator layers– Specific cell & strip combined clustering must be developed.

• Mokka simulation of the hybrid-type ECAL is under preparation.

Two-fold ambiguitywith strip clustering

Si pads(5x5 mm2)

Scint strips(5-10 x 45 mm2)

S. Uozumi@ILDWS2010


Simulation studies are about to start for optimization.

Hybrid ECAL• ScECAL with strip-splitting method has shown good performance

(stochastic term < 30% at Z pole), close to the SiECAL performance.• There should be optimum combination of SiECAL and ScECAL for

ILD Hybrid ECAL with good performance and reasonable cost.


Sc/(Si+Sc)

Performance Cost

Low

high

high

low

Hybrid ECAL (cont’d)• Hardware R&D:

– ECAL technological prototype will have both Si-pad and scintillator-strip layers: good experience to operate two different technologies simultaneously in a same mechanical structure.

• Simulation studies for optimization– Hybrid ECAL geometry has been already implemented in Mokka.– Strip-splitting method to be implemented in MarlinReco soon.– Tamaki (Kyushu) and new Posdoc@LLR will work on this study.– Various combinations to be studied, for example:

• SiSiSi…SiSiSiScScSc…ScScSc• SiSiScScSiSiScSc…SiSiScScSiSiScSc• ScSc…ScScSiSi…SiSiScSc…ScSc


MAPS (DECAL) option• Potential large cost reductions

– Standard CMOS sensor– No proprietary processes– Electronics all on sensor, reduced

fabrication/assembly costs• Ultimate spatial resolution

– 50x50 μm2 pixels– “TERA Pixel” detector

• TPAC readout chip v1.0-v1.2 = 168 x 168 pixels; 79.4 mm2

Expected resolution (pixel counting) 13%/√E(GeV) 1%⊕• Status:

– successful CERN TB of 6 sensors summer 2009

– New SPiDeR collaboration – Physics prototype planned for 2012

• Critical points– integration, Power consumption,

services– Funding issue for further R&D

S. Uozumi@ILDWS2010


Because of funding problems in UK, currently no plan for physics prototype DECAL. Apart from sensor R&D being continued, only simulation studies have been carried out recently.

DECAL Status Recent resolution studies using HZ/ZZ 4-jet events and qq pairs

ILCSoft v01-10, Mokka 07-06, QGSP_BERT. Use old ILD_00 model, direct comparison of

DECAL and SiW (trivially adapted SECal03 driver for DECAL). MarlinReco v00-19, IldCaloDigi, PandoraPFANew v00-04.

Jet energy resolution extracted with full PFA, 2 very different environments ZZ/HZ case: bin hadronic jets according to their energy, (all at s = 500

GeV) pairs, 10 energies, s = 50-500 GeV

Energy resolutions obtained in our studies (4-jet topology) DECAL (25.5±0.6)%/√E

(analogue) SiW (22.3±0.5)%/√E

pairs, DECAL (4.9±0.2)%/√E

(analogue) SiW (4.8±0.2)%/√E

DECAL performance comparable with baseline ECAL options

More straightforward qq (uds) jet resolution, no ISR, etc. to be done 11/05/23ECAL review K. Kawagoe

Reco’d PFOs

Sim

N. Watson

SummaryECAL group is working toward DBD with a strong international collaboration.•SiECAL

– Physics prototype: successful operation of 6 years at TB – Technological prototype being constructed

• to establish necessary technology for ILD: sensors, ASIC, PCB, Integration, DAQ, Mechanical structure, and cooling.

• First (small) test will start in this year.•ScECAL

– A few layers to be integrated into the technological prototype– Progress in Strip-clustering, 5mm strips, new MPPC.

•Hybrid ECAL (SiECAL+ScECAL)– is considered seriously, and intensive studies are starting for

optimization.•MAPS DECAL, currently having financial problems for its R&D, may be considered as an option beyond DBD. 11/05/23 ECAL review K. Kawagoe 23

ecal review 5 th ild workshop @ lal orsay 23-25 may 2011 k. kawagoe kobe-u kyushu-u in april 2011

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