The High Momentum Particle Identification Detector (HMPID) of ALICE at LHC;

1. 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.

2. Seven HMPID modules with 11m2 of CsI photosensitive surface. The external module’s sizes are about 1.5x1.7x0.5 m3 Distance vertex-module = 4.5 m • ALICE is devoted to study strongly interacting matter at extreme energy density (1-2 GeV/fm3) • The Highest expected multiplicity in Pb-Pb collision at LHC is : dNch/dy ~ 6000-8000, corresponding to about 80 charged particles/m2 at 4.5 m from the interaction point (10-12% pad occupancy ). HMPID layout in ALICE at LHC The HMPID layout is such to maximize the acceptance of high pt particles in |h| <1

3. , qp qc THE HMPID BASIC ELEMENTS Proximity-focusing geometry Radiator: 15 mm C6F14; n=1.2989 @ 175 nm Photon converter: 300 nm thick reflective layer of CsI; QE 23% @ 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. (b=1, norm inc) • 1 < p < 3 GeV/c p, K • 1.5 < p < 5 GeV/c p

4. 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

5. 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)

6. 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 PCB’s on aluminum frame (vacuum table).

7. CECOM CERN-Marbre Planarity CERN- 4 block CECOM CERN 3-point 0.1 CERN-Marbre remachined- CERN CERN- 4 block 0.08 CERN 3-point Remachined - CECOM remachined- CERN 0.06 Remachined - CECOM mm 0.04 0.02 0 0 10 20 30 40 50 60 frame number 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

8. The header tube acts as a hydrostatic gravity feed for the radiator to have “implicit” pressure control/safety for quartz radiators Liquid distribution system:basic elements and layout

9. Thomson-weir angle of 30 ° to control the liquid flow to about 1 volume exchange every 2 hours reference gas Input pipe purging pipe to radiator input Header tubes and pipe layout Height = 400 mm Diameter = 100 mm Weir angle = 30° Fluid Volume = 2,53 liters Total Volume =3,14 liters

10. 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 ch’s 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

11. Cooling system:operating principles

12. 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 Cooling Sub Sys CU Domain Low voltage Sub Sys CU Domain High Voltage Sub Sys CU Domain Gas Distrib. Sub Sys CU Domain Liquid Circulat. Sub Sys CU Domain LVm 1 HVm 1 ? ? LCMain LCModul LVm 2 HVm 2 LVm 3 Device Units HVPS 1 HVm 3 LVm 4 HVm 4 LVm 5 HVm 5 LVm 6 HVm 6 LVm 6 HVm 7

13. DCS LOGICAL UNITS + 5 2x (MCM+……….) Segments MCM4 _ MEM MCM5_ MEM MCM1_MEM MCM2_ MEM MCM3_ MEM _DDL MCM3_ MEM_DDL 6 x FEE Segments, 240 GASS. each - 5 6 xHV Segments, 48 wires each FEE 6 FEE 4 FEE 3 FEE 1 FEE 5 FEE 2 Power requirements/SEGMENT V A W FEE+ +2.8 5.6 16.0 FEE- -2.8 6.8 19.0 MCM_MEM_DDL+ +5 12 60.0 2 x MCM_MEM + +5 14 70.0 MCM (half detect.)- -5 2.5 12.5 TOTAL power /HMPID module 495 - 5 + 5 H6 H1 H2 H3 H4 H5 LV-HV Sub-systems:the detector segmentation

14. HMPID CS Main Panel

15. 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

16. Ready for physic Rad. purging Main tank level Stand by C6F14 Rad. level LCS Trend Panel ( HMPID – DCS Lab Test 13/09/2001 )

17. CONCLUSIONS After ten years of R&D activities, an array of seven proximity focusing RICH modules is being built to identify p-K in the range 1 < p <3 GeV/c and protons in the range 1.5<p<5 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 MWPC’s with high QE CsI segmented photo-cathodes for the Cherenkov photon conversion.

18. 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 mm213.8 VDD/VSS V ±2.8 Noise e- r.m.s. 530 @ 0 pF (~1000 on det.) Noise slope e- r.m.s./pF 11.2 Linear Dynamic range fC > 500 Conversion gain mV/fC 3.6 Base line recovery< 0.5% after 5 s Peaking times1.1 - 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

19. Details of the HMPID layout on the cradle