1. S. K. PalDCS WORKSHOP 17 JUN 2002 FRONT VIEW PMD Layout and Design Two planes: Veto + PreShower Gas detector with hexagonal cells Cell cross section: 0.22 cm 2 Cell depth: 0.5 cm Total No. of channels: 169,344 Distance from vertex: 355cm  Coverage: 2.3 – 3.5 Area of the detector: 1.8m 2 Ave. Occ: 13% for CPV & 28% for PMD Photon counting Efficiency: 64% & purity: 60% CPVPreShower

2. S. K. PalDCS WORKSHOP 17 JUN 2002 FEE Board Mounting and Cooling 4 chip MCM board with MANAS-16 (similar to that of station 3-4-5 of Dimuon Tracking) PMD Front-End Electronics

3. S. K. PalDCS WORKSHOP 17 JUN 2002

4. S. K. PalDCS WORKSHOP 17 JUN 2002 PMD Control System The Control System of PMD will consist of following subsystems: 1. High Voltage System 2. Gas System 3. FEE - Low Voltage System - Cooling System PMD Readout Chambers High Voltage Low Voltage Cooling Gas LV Crate HV Crate Temp. Flow FEE Air Flow

5. S. K. PalDCS WORKSHOP 17 JUN 2002 Schematic of LV Control System LV PS Distribution Box ‘N’ Power Supply Lines (Current ‘I’ in each Line) One Power Supply Line (Current ‘N*I’ in line) Control ‘On/Off’ FEE Read out Monitoring CAN Filed Bus ~50m No. of LV Chains : 180 Voltage : +/- 2.75V, +5V Current : 5A/Chain Model : PL500 from Wiener, 3U size Interlock : With cooling Alarms : depending on current limit / channel

6. S. K. PalDCS WORKSHOP 17 JUN 2002 Schematic of HV Control System HV PS Distribution Box ‘N’ Power Supply Lines (Current ‘I’ in each Line) One Power Supply Line (Current ‘N*I’ in line) Control ‘On/Off’ SM Monitoring CAN Filed Bus ~50m No. of HV Chains : 60 Voltage : - 2000V Current : 100 uA/Channel Model : ISEG or SY1527 Interlock : With Gas sub system Alarms : depends on currents/channel

7. S. K. PalDCS WORKSHOP 17 JUN 2002 PMD Cooling Setup to find out if Air Cooling is adequate for the PMD-FEE.

8. S. K. PalDCS WORKSHOP 17 JUN 2002 Effectiveness of forced air cooling can be seen here.

9. S. K. PalDCS WORKSHOP 17 JUN 2002 Gas ratio : Ar : Co 2 ( Ratio 70: 30) Monitoring : Required Interlock : With HV System Gas Sub System Cooling Sub System Alignment : - Few monitoring places Control Parameters : - Air flow - Temperature, 60 points wit pt100 Interlock and Alarms : - Interlock with LV Power supply System - Alarms if Temperature is not within limit

10. S. K. PalDCS WORKSHOP 17 JUN 2002 PMD Measures: Multiplicity and spatial distribution of photons on an event-by-event (E-by-E) basis Physics Goals: (1) E-by-E Multiplicity Fluctuation (2) Disoriented Chiral Condensates (3) Event shapes and Flow PMD Design: Recap from LHCC-2001: Pre-shower detector having fine granularity. PMD relocation from 580cm to 355cm – ITS & TPC services, Beam pipe, pump Necessitated smaller cell size ALICE PMD

11. S. K. PalDCS WORKSHOP 17 JUN 2002