A CsI based RICH for the identification of high momentum particles in ALICE G. De Cataldo, on the behalf of the ALICE-HMPID team

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A CsI based RICH for the identification of high
momentum particles in ALICEG. De Cataldo, on the
behalf of the ALICE-HMPID team

• The High Momentum Particle Identification
  Detector (HMPID) of ALICE at LHC
• Operating principles and module elements
• The C6F14 liquid distribution system
• The FEE-RO basic elements
• The Cooling system
• HMPID Control System in the JCOP Framework
• Conclusions.

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HMPID layout in ALICE at LHC
The HMPID layout is such to maximize the
acceptance of high pt particles in h lt1
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THE HMPID BASIC ELEMENTS
Proximity-focusing geometry
Radiator 15 mm C6F14 n1.2989 _at_ 175 nm
Photon converter 300 nm thick reflective layer
of CsI QE ? 23 _at_ 7.1 eV (175 nm)
Photoelectron detector MWPC 2 mm gap with CH4 at
atmospheric pressure, gas gain ? 105 and analogue
pad read-out ( pad size 8x8.4 mm2, total
channels ? 160 K)

• PID range
• sqc 12.8 mrad/single pe. (b1, norm inc)
• 1 lt p lt 3 GeV/c p, K
• 1.5 lt p lt 5 GeV/c p

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Module elements
6 photo-cathode panels
Mechanical details
protective box
Al main chamber frames 1 trough 4
proximity gap 80 mm
quartz
rad. thickness 15 mm
3 quartz radiator trays
composite panel
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HMPID display during SPS beam tests
A HMPID prototype, 2/3 in size, equipped with 4
photo-cathodes, tested at CERN first then shipped
and installed in the STAR experiment at BNL, is
now data taking at RHIC since 2000 (see Gerd
Kunde talk)
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CsI photo-cathode

• The CsI photocathode is based on
• ? standard multi-layers PCB
• ?G10-Cu-Ni-Au as substrate for the CsI
• SMD connectors to plug-in the FEE cards
• ?Au deposition by electrolytic procedure
• ?Tooling for gluing PCBs on aluminum frame
  (vacuum table).

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MODULE 1 ASSEMBLING
Metrology controls on the pad panel frames
mm
Tolerances on the planarity - Pad panel frames
0.05 mm - main chamber frames 0.1 mm
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Liquid distribution systembasic elements and
layout
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Header tubes and pipe layout
Height 400 mm Diameter 100
mm Weir angle 30 Fluid Volume 2,53
liters Total Volume 3,14 liters
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MAIN FEE and RO COMPONENTS
FROM THE PAD PLANE
COMMERCIAL 12 bit ADC
Basic FEE card plugged on the pad cathode panel
DILOGIC, DIGITAL ASIC 12-bit amplitude input
data, 6 bit add. 9-bit threshold pedestal, 20
MHz , 60 mW/64 chs power consumption,
Asynchronous read/write operation, 512 18-bit
words output FIFO, Several chips can be
daisy-chained on the same 18-bit bus.
GASSIPLEX, 16 ch ANALOGUE ASIC
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Cooling systemoperating principles
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HMPID Control System

• This Control Domain Hierarchy is implemented in
  the JCOP Framework by means of the Finite State
  Machine (FSM) tool kit
• The system is defined by 6 Control Units, one for
  each sub-system and one for the whole detector

HMPID Control Unit Domain
Control Units
High Voltage Sub Sys CU Domain
Low voltage Sub Sys CU Domain
Gas Distrib. Sub Sys CU Domain
Liquid Circulat. Sub Sys CU Domain
Cooling Sub Sys CU Domain
LVm 1
HVm 1
LCModul
LCMain
?
?
LVm 2
HVm 2
Device Units
LVm 3
HVPS 1
HVm 3
LVm 4
HVm 4
LVm 5
HVm 5
LVm 6
HVm 6
LVm 6
HVm 7
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LV-HV Sub-systemsthe detector segmentation
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HMPID CS Main Panel
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HV channel monitoring Panel PS Test Beam
(October-2001) CAEN SY1527-A1821P board, readout
via OPC server
HV Channel Status
HV Channel Setting Values
Channel Imon
Channel Vmon
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LCS Trend Panel ( HMPID DCS Lab Test
13/09/2001 )
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CONCLUSIONS
After ten years of RD activities, an array of
seven proximity focusing RICH modules is being
built to identify p-K in the range 1 lt p lt3 GeV/c
and protons in the range 1.5ltplt5 GeV/c in the
ALICE experiment at LHC. The HMPID, with a total
active area of 11 m2, working fine in magnetic
fields, represents the largest scale application
of MWPCs with high QE CsI segmented
photo-cathodes for the Cherenkov photon
conversion.
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GASSIPLEX technical specifications
? 16 Analogue multiplexed channels, up to 60
chips in daisy chain, TRACK HOLD ?Dedicated
filter to compensate the long ion drift
tail ?Internal protection against discharges
Technology
ALCATEL-MIETEC 0.7 Silicon Area
mm2 13.8 VDD/VSS
V
2.8 Noise e- r.m.s.
530 _at_ 0 pF (1000 on det.) Noise
slope e- r.m.s./pF
11.2 Linear Dynamic range fC
gt 500 Conversion gain mV/fC
3.6 Base line recovery
lt 0.5 after 5 ?s Peaking
time ?s 1.1
- 1.3 Power consumption mW
128 Analogue readout speed MHz
10 Package
MQFP 64 L 15.000 chip
already delivered and now under test in Bari
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Details of the HMPID layout on the cradle