ALICE PMD PRR

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ALICE PMD PRR
Agenda
Morning B. Sinha Welcome Y. Viyogi Introduction
to PMD and scope of PRR M. Ganti Detector
fabrication and tests M. Dutta-Majumdar Quality
Assurance T. Nayak Test results of
pre-production prototype Y. Viyogi Planning and
scheduling Afternoon All Lab visit and
discussions
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Photon multiplicity detector (PMD)
Photon Multiplicity Detector (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.
PMD probes thermalisation (flow), phase
transition (multiplicity fluctuation), Chiral
symmetry restoration (charged-neutral fluctuation)
Bhubaneswar-Chandigarh-Kolkata-Jaipur-Jammu
SPS ? RHIC ? LHC
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Principle of a preshower detector
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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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Contribution to QGP physics at a glance
? Thermalisation First observation of elliptic
flow at SPS Directed and elliptic flow of
neutral pions ? Chiral symmetry
restoration Limits on domains of Disoriented
Chiral Condensates ? Phase transition Multipli
city fluctuation of photons and charged particles
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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. Reduce cross-talk stop ?-rays within a
cell Use neutron-insensitive gas mixture (Ar
CO2) ? Honeycomb gas proportional counter
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Honeycomb proportional chamber
PCB
Cathode extension
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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Evolution of honeycomb PMD
ALICE PMD TDR cell size 1 cm2, depth 5
mm Rhombus unit modules and supermodules Adapted
for STAR PMD ALICE PMD re-incarnation cell
size 0.22 cm2, depth 5 mm Rectangular geometry
after STAR PMD experience
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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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PMD _at_ STAR(identical with ALICE PMD TDR design)

• 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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Benefits from STAR PMD work
Infrastructure Manpower Experience with large gas
detector
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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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PMD in ALICE _at_ LHC
PMD Z360
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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 No. of cells in
a UM 4608 No. of HV channels 48 Signal
processing MANAS
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Works scheduling within PMD team
For SPS Manpower trained during WA93 PMD work at
VECC About half the padsfibre work done at other
centres for the WA98 PMD. For RHIC/LHC manpower
trained during numerous prototype fabrications
and in special training sessions at
VECC. Facilities for detector assembly setup at
VECC, IOP, Jammu. For STAR PMD, 15 unit modules
made at Jammu, 15 at IOP.
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Scope of PRR
Detector fabrication Fabrication and assembly of
unit modules and supermodules, quality control,
performance study
Auxiliary systems after more study and
design Electronics identical with Muon Arm
Tracking chamber
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Planning and scheduling UM assembly
Wire insertion
4 weeks
Visual inspection
3 days
Resistance measur.
1 week
Wire cutting
1 week
Visual inspection
3 days
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Planning and scheduling UM tests
Test setup ready and gas-tight
2 days
HV endurance tests
8 days
Tests with FEE boards
1 week
Cosmic tests
2 week
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Planning and scheduling SM assembly
SM assembly all the components made in
parallel Actual assembly time minimal
SM tests
SM tests similar to that of UM
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Planning jobs in parallel
Six stations for UM assembly (3 at Kolkata, 2 at
Jammu, 1 at Bhubaneswar) 6 UMs
every two months 48 UMs in 16 months Tests of
UMs 3 to 4 UMs tested in parallel (staggered
operation) Cosmic tests stacking of UMs.
SM assembly serial (all at VECC), but can be
taken up as and when 6 UMs ready and
tested. Tests of SMs time similar to that of
UMs except HV endurance tests.
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Material procurement
Honeycomb submodules, Al-boundary channels
procured. Connectors, PCBs, wire
vendorsidentified, tendering to go after
PRR. Jigs/fixtures/tooling partly available,
rest can be easily obtained (local supply).
MILESTONES
Target date for start of UM assembly April 1,
2004 Target date for start of SM assembly
Sept. 1, 2004