24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL1 The STAR Photon Multiplicity Detector Supriya Das, VECC Kolkata For The STAR PMD Collaboration Junior’s Day STAR Collaboration Meeting, BNL Outline of the talk:  Physics goals  Working principle of the detector  Design and fabrication aspects  Test results  Installation  DAQ, Trigger and Slow control  Simulation and offline reconstruction software  Summary

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL2 What does it do? We measure the multiplicity and spatial distribution of photons (  dN/d  etc) to study: The azimuthal anisotropy to determine the reaction plane and flow as the probes of thermalization. The event by event fluctuations in global observables like multiplicity and pseudorapidity distributions following critical phenomena near phase boundary. The distribution of N  and N  /N ch with full azimuthal coverage ( the charged particles info will be taken from FTPC), looking for signals of chiral symmetry restoration (e.g. DCC).

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL3 Recollection from past… Observation of collective flow Phys. Lett. B403 (1997) 390. Scaling of particle production: Phys. Lett. B458 (1999) 422. DCC Search: Phys. Lett. B420 (1998) 169 Phys.Rev.C64:011901,2001 Fluctuations: Phys. Rev. C, May 2002 Scintillator + CCD readout detector sitting 21.5 meters from the vertex covering  to 

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL4 Two planes CPV+Preshower Gas detector of hexagonal cells Cell cross section : 1.0 cm 2 Cell depth : 0.8 cm Gas used: Ar+CO 2 in 70:30 Total number of channels : 82,944 Distance from vertex : 550 cm  coverage: 2.3 – 3.8 Area of the detector : 4.2 m 2 CPV PreShower Preshower detector : 3X 0 Pb convertor sandwiched between two planes of segmented gas detectors. Charged particle gives single cell signal in both the planes, photon gives restricted shower signal on the second plane How does it work?

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL5 One Unit Module has 576 cells. Different Supermodules has different number of unit modules (4,6,9 etc.) depending on the position on the detector Each plain has 12 Supermodules 144 unit modules Supermodules are Gas tight and HV isolated Whole detector can be separated in two halves Different features of PMD

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL6 Cathode Material: 0.2mm thick copper sheet Anode wire: 20  m gold plated Tungsten Anode wire Tension : 25 grams End caps: standard 1.6 mm thick FR4 PCB The single cells (shown above) have solder coating on the outer surface. They are assembled on a special jig (shown on the right) and fused together under controlled heat. Single Cell Design

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL7 Unit Module Components Gas - 4 board plugged onto the connector Each unit module contains 24x24 array of cells (576) Size of unit module: Rhombus of side 255 mm Weight of unit module: 700 gm Unit Module construction

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL8 STAR PMD Supermodule assembled in Laboratory

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL9 Front-end Electronics The front-end electronics for processing PMD signals uses 16-channel GASSIPLEX chips. Gassiplex Chip Testing 10,000 chips have been tested for the full functionality of each channel. Test board for GASSIPLEX The chip

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL10 Translator Board: Needed to shift the logic level of the control signals (CLK, CLR and T/H) from fast NIM to that of the GASSIPLEX chips. Gas – 4 Boards: Contains 4 GASSIPLEX boards and necessary discrete components. Two protection boards with twin series diodes for each channel is also plugged in. Buffer board: Needed for the impedance matching of the analog signal and the input impedance of the ADC in C-RAMS. Different Front end boards

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL11 Tests performed on the Supermodule: Gas leak test HV test Pedestal with FEE boards Signal with cosmic muons Supermodule under test in laboratory

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL12 Test Setup at CERN-PS June 2002 STAR PMD Supermodule

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL13 Supermodule Test Results I Pion beam at 5 GeV/c # of cells hit = 1.091Pulse height spectrum Variation of Efficiency & Pulse height with Voltage

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL14 Test with electron beams Preshower spectra Calibration curve Supermodule Test Results II

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL15 PMD in Wide Angle Hall

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL16 The suspension mechanism for PMD

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL17 PMD Installation

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL18 One Unit Module (UM) consists of 24x24 = 576 cells One UM has 9 Gas - 4 Boards each with 4 chips (= 64 Multiplexed channels per board) 3 of UM are daisy chained in ONE FEE Chain In ONE Chain: 27 Nos. Gas-4 boards i.e. 27x64 = 1728 channels In total there are 72 UM per plane. Two planes: 72 x 2 = 144 Unit Modules. Total Number of FEE chains 144/3 = 48 One C-RAM has 2 Blocks One Block = 2K Channels and Total 4K Channels/C-RAM 1728 channels/Block i.e. ONE chain/Block will be used Total Nos. of C-RAMS required are 24. DAQ:Number of Chains and C-RAMS

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL19 PMD trigger timing diagram

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL20 Typical pedestal plot for one FEE chain

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL21 CAN BUS VME Crate for DAQ(pmd02) VME Crate for DAQ(pmd01) NIM Crate for CLK,CLR,T/H NIM Crate for Trigger Elec. Motor Movement Control(PMD) PL-500 LV unit VME Crate for HV Control Network Power Switch Ethernet Hub for DAQ Network Ethernet Hub for Slow Control Network PC-Ethernet PC-CAN-USB HV Console CAN BUS Host PC To Main DAQ Network To Main Slow Control Network Fibre Optic RACK-1 RACK-2RACK-3 HV Serial Slow Control for PMD at STAR LeCroy 1454 HV Unit MVME 167B

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL22 10 Supermodules have been installed in the last shut down period. 7 FEE chains have been installed and tested. Pedestal taken for all seven FEE chains. Slow control for Cathode High Voltage, FEE Low Voltage and VME crates have been set up and working. Suspension and moving mechanism for PMD has been installed on the east wall of the WAH. The stainless steel support plate and lead converter plates have been installed. Journey so far … All LV, HV and signal cables including various optical cables have been laid. Gas supply and distribution system has been installed.

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL23 Implementation in GSTAR Front view of PMD in GSTAR PMD with other detectors PMD

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL24 Offline reconstruction framework

24th. February, 2003Supriya Das : Junior’s Day, STAR Collaboration Meeting, BNL25 Summary Photon Multiplicity Detector is a preshower detector which measures the multiplicity and spatial distribution of photons in the forward region of STAR. In combination with the charged particle data from the FTPC, it studies different important physics aspects. A major portion of the detector has already been installed. Looking forward for data from d+Au and p+p runs for detector Calibration and understanding of the different aspects of the detector. Getting ready for real physics data from Au+Au run. The DAQ, Trigger and Slow control systems has been set up.