Detector development for heavy ion colliders : Indian contribution

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Detector development for heavy ion colliders
Indian contribution
Y.P. Viyogi Variable Energy Cyclotron Centre,
Kolkata (e-mail viyogi_at_veccal.ernet.in)
Heavy ion experiments Study of Quark-Gluon
Plasma SPS experience Challenges of high
multiplicity at colliders RHIC and LHC Photon
Multiplicity Detector for STAR _at_ RHIC and ALICE
_at_ LHC Cathode pad chambers for muon tracking in
ALICE MANAS a signal processing ASIC for ALICE
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The complexity of multiplicity
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Photon multiplicity detector (PMD)
PMD a preshower detector measuring spatial
distribution of photons in the forward rapidity
region Complements the study of photons in the
forward region where calorimeter cannot be used
due to high particle density.
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PMD_at_SPS
At SPS (WA93/WA98 Experiments) Scintillator pads
with wavelength shifting fibres read out using
image intensifier CCD camera systems. 3 X0
thick Lead converter Scintillator pads of size
10, 15, 20, 25 mm2

• WA93 (S Au, 200AGeV) 8000 pads covering
  3m2
• WA98 (Pb Pb, 158 AGeV) 53000 pads covering
  21m2

Building blocks of PMD
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PMD _at_ SPS
WA93
WA98
Bundle of 1900 fibres
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PMD _at_ colliders
At RHIC and LHC (STAR and ALICE experiments)
PMD in forward region Detector design criteria
Confine charged particle hits to single cell to
improve photon-hadron discrimination and
restrict occupancy Reduce cross-talk stop
?-rays within a cell Use neutron-insensitive gas
mixture (Ar CO2) ?
Cellular gas proportional counter with honeycomb
geometry
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Honeycomb proportional chamber
Copper honeycomb Closest to circular
geometry Excellent packing Wall to stop
?-electrons
PCB
Cathode extension
Cathode at high negative potential, Anode wire at
ground potential connected to readout.
Extended cathode design a novel idea to achieve
uniformity of response throughout the cell volume
design with GARFIELD
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Results of GARFIELD simulation
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Gain variation within a cell
Extended cathode
Open geometry
NIM A488 (2002) 131
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Building blocks of honeycomb detector(STAR PMD)
Top and bottom cover With printed circuit boards
70-pin connector
Front-end electronics Boards with 4 gassiplex
chips
Copper honeycomb
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Response to charged particles(typical results)
5 GeV/c pion
Av. Eff. 97
Cell-to-cell uniformity 7
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STAR experiment at RHIC, BNL
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PMD _at_

• Preshower Detector with fine granularity
• Two planes Veto Pre-shower
• h Coverage 2.3 3.9
• Total no. of cells 82,944
• Distance from vertex 550cm
• Cell cross section 1.0 cm2, depth 0.8 cm
• Readout GASSIPLEX 0.7-3 C-RAMS
• 24 Supermodules, 144 Unit modules
• Rhombus geometry of unit modules

PMD front view
Joining of two halves
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Unit module assembly
Quality assessment PCBs before mounting after
soldering after gluing Wire insertion,
tensioning jig and soldering (delicate needle
work)
Resistance meas. for one UM
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STAR PMD in Wide Angle Hall
Preshower plane
Veto plane
STAR PMD installation completed, ready for data
taking Jan. 2004
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TOF
TRD
HMPID
TPC
PMD
ITS
Muon Arm
Indian contribution to ALICE Preshower PMD
(honeycomb chamber) Second station of Muon
Spectrometer (cathode pad chamber) MANAS signal
processing ASIC for Muon Arm and PMD
PHOS
ALICE Set-up
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PMD in ALICE _at_ LHC
PMD Z360cm
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PMD in ALICE
?,? coverage 2.3-3.5, 2? Distance from IP 361.5
cm Cell cross-section 0.22 cm2 Cell depth 0.5
cm No. of SMs 8 No. of UMs 48 Total no. of
cells 221184 No. of HV channels 48 Signal
processing MANAS
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ALICE PMD pre-production prototype
Two unit modules, each with 2304 cells Tests at
CERN Sept. 2003
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Dimuon Spectrometer
ALICE
Requirements of dimuon tracking chambers for
energy resolution of 100 MeV for J/?
1. Position resolution lt ?100 microns for track
through five stations (lt 70 microns for
St.2). 2. Thickness lt 2 of X/X0 (ultra-light
material). 3. High granularity and low occupancy
of pads.
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Cathode pad chamber for muon tracking
Three different pad sizes Plastic (PEEK-GF30)
frame Flexible PCB (kapton) to connect pads to
MCM board Occupancy in the bending plane lt 6
Detector Quadrant Zero, Station 2 Oct 2003.
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Total charge spectrum from cathode
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Test results (typical)
Gain variation lt 15
Gain vs Voltage
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Signal processing ASIC
16-channel signal processing ASIC (pre-amp,
shaper, track-and-hold with analog multiplexed
output) Developed by Saha Institute of Nuclear
Physics, Kolkata Fabricated at Semiconductor
Complex Ltd. Chandigarh
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MANAS
Silicon area 2.7x4.7 mm2 Peaking time 1.2
?s Noise at 0pF 640 e- rms Noise slope 11.58 e-
rms/pF Dynamic range () 500 fC Dynamic range
(-) 275 fC Sensitivity () 3.75
mV/fC Sensitivity (-) 3.27 mV/fC Readout speed
10 MHz (max) Power consumption 7
mW /channel Temperature coeff. 0.03 mV/0C
Layout of ceramic packaged MANAS
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MANAS test results
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Gain Distribution of 500 plastic packaged
pre-production MANAS chips
Noise 1125 electrons
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Position resolution with single-point gain
calibration of MANAS
July 2003 in-beam test
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Summary
Indian contribution to Heavy Ion Collider
experimental program significant PMD has been a
flag bearer for the last 12 years Joined by CPCs
now Good expertise in gas detectors With MANAS,
the contribution comes to electronic age
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Groups involved in various activities

• PMD
• Variable Energy Cyclotron Centre, Kolkata
• Institute of Physics, Bhubaneswar
• Panjab University, Chandigarh
• University of Rajasthan, Jaipur
• University of Jammu, Jammu
• Tracking chambers
• Saha Institute of Nuclear Physics, Kolkata
• Aligarh Muslim University, Aligarh
• MANAS ASIC
• Saha Institute of Nuclear Physics, Kolkata
• Semiconductor Complex Ltd. Chandigarh