TPC/HBD R&D C.Woody, N.Smirnov, B.Azmoun, M.Sivertz, B.Yu, R.Majka, J. Mitchell, V.Rykov, M.Purschke, C.-Y.Chi PHENIX Collaboration Meeting Nashville, TN June 11, 2003

C.Woody, Nashville Collaboration Meeting, 6/11/032 List of Topics  GEM measurements with Ar/CO 2 and CF 4  Status of new GEM foils  Gas transmission measurements  TPC field cage design  Tracking Issues with TPC and VTX  Electronics for the HBD and TPC  R&D plan for next year

C.Woody, Nashville Collaboration Meeting, 6/11/033 GEM configuration Initial tests with GEMs using CF 4 did not produce usable signals Problem was with electric field in transfer gaps Smaller gap spacing and higher fields (> 2 kV/cm) give much higher gains

C.Woody, Nashville Collaboration Meeting, 6/11/034 GEM Measurements with Ar/CO 2 BNL WIS Resistive divider Fix V TG Vary V F Fix V F Vary V TG We seem to get higher gain at the same voltage than WIS At fixed V TG the gain curve is nicely exponential as expected up to ~ 10 5 where discharging starts to occur Varying V TG at fixed V F has a much weaker effect on gain, but shows no plateau up to the maximum V

C.Woody, Nashville Collaboration Meeting, 6/11/035 GEM Measurements with CF 4 Resistive divider Fix V TG Vary V F Fix V F Vary V TG We again seem to get higher gain at the same voltage than WIS Both BNL and WIS see saturation in CF 4 at gain ~ 10 5 (before breakdown point) V TG again has a much weaker effect on gain and shows no plateau BNL WIS

C.Woody, Nashville Collaboration Meeting, 6/11/036 New GEM Foils from 3M Expecting delivery of 50 new 10x10 cm foils at BNL in ~ 2 weeks Roll-to-roll process Limited to 12” width 3M Microinterconnect Systems Division, Austin, TX In collaboration with Univ. Chicago (J.Collar) hep-ex / (April 2003)

C.Woody, Nashville Collaboration Meeting, 6/11/037 Testing Small 3M Foils 3 stage GEM with three 1” dia. 3M foils 80 m m (55 m m) holes spaced in a hexagonal pattern with 140 m m pitch Visually looks to be excellent quality Will compare with CERN foils in Ar/CO 2 & CF 4

C.Woody, Nashville Collaboration Meeting, 6/11/038 VUV Transparency of Potential Radiator Gases VUV transparency is extremely sensitive to O 2 and H 2 O content Tranmittance of Argon and CF 4 Gas system being developed and tested in collaboration with LEGS B.Azmoun

C.Woody, Nashville Collaboration Meeting, 6/11/039 Low O 2 and H 2 O levels are critical for good VUV transparency Ref.: Zaidel’ & Shreider, VUV Spectroscopy Water Vapor. Oxygen.

C.Woody, Nashville Collaboration Meeting, 6/11/0310 Absolute Quantum Efficiency of CsI photocathodes CsI PMT Comparison of our CsI photocathodes with a calibrated CsI PMT Good quality CsI photocathodes are now being made at Stony Brook Stack with Au coated GEM foil for depositing CsI photocathode VUV Spectrometer

C.Woody, Nashville Collaboration Meeting, 6/11/0311 TPC Field Cage Design Question: How uniform can we make the drift field and how large are the electric field distortions near the edges and in the vicinity of the HBD ? Autocad geometry  MAXWELL Not so easy…. Also try 2D calculation using GARFIELD N.Smirnov

C.Woody, Nashville Collaboration Meeting, 6/11/0312 Drift Field Distortions N.Smirnov GARFIELD MAXWELL E Z / E R / R Drift field distortions are generally < 1%

C.Woody, Nashville Collaboration Meeting, 6/11/0313 Electric Field Distortions Near the HBD 30 cm mini TPC field cage wires 3 mm 5 cm -36 kV 0 V + 75 V wire plane with 5 mm step N.Smirnov Initial indications are that the electric field distortions in the region of the HBD are small, but we need to do more calculations E D, V/cm E R, V/cm

C.Woody, Nashville Collaboration Meeting, 6/11/0314 Tracking Issues Need to begin serious simulation work on pattern recognition, track finding and track fitting using tracking information from all PHENIX detectors (present and future - VTX and TPC) V. Rykov ++ Configuration B = 9 KG Momentum resolution for various combinations of the VTX and TPC TPC would be used for tracking not only in the electron pair measurement in conjunction with the HBD, but also as an additional tracking detector in normal field running. Helps in rejecting false high P T tracks and provides good stand alone tracking for tracks presently outside the PHENIX acceptance (useful for jet measurements)

C.Woody, Nashville Collaboration Meeting, 6/11/0315 Is this PHENIX or STAR ? J.Mitchell’s event display of the PHENIX TPC for a central Au-Au event (PISA simulation) Investigating TPC pattern recognition software from LBL (LC) and STAR (Level 3)

C.Woody, Nashville Collaboration Meeting, 6/11/0316 Readout Electronics Currently reading out GEM TPC with 100 MHz FADC (SIS channel, 12 bit VME module) pDAQ courtesy of M.Purschke FADC readout (10 ns bins)Digital scope trace 55 Fe source with 10x10 cm 2 triple GEM

C.Woody, Nashville Collaboration Meeting, 6/11/0317 Future HBD/TPC readout electronics development Try and utilize existing or soon to be available components HBD needs only modest (~ few ns) time resolution Perhaps can use FADC to provide time information 32 ch preamp/shaper for APD readout 0.18 m m CMOS, 125 mW per chip Final ASIC 4.3 x 1.6 mm 2 65 MHz FADC available soon

18 TPC and HBD electronics R&D: 1) can use the same type of electronics for both HBD and TPC ??? (by fitting ADC samples to get T0) 2) TPC FEE issue: Heat load and high channels count => custom ASIC or commercial ADC+ FPGA In the next few months we will construct a possible commercial ADC + FPGA for the TPC readout solution base on Analog Device 4 channel 8 bit ADC (chips scale BGA serial ADC) This is to understand power + readout + packing density issues This will also serve as preliminary study for the HBD readout… TPC FEE: Samples signal every 25ns for 140 samples. need L1 delay buffer (160 samples) + 5 events buffers (700 samples) HBD FEE: Need to measure charge and time (~ several ns) L1 delay buffer + 5 events buffers. C.-Y.Chi, Nevis

19 For TPC FEE : 60K to carry out TPC FEE study + 20 K (M&S) 1) study commercial IC solution 2) study the issues regard to custom ASIC a) follow ALICE path – buy ADC core + custom Logics b) fully custom ASIC ( need to use commercial library) 3) building prototype modules ( commercial solution) or custom ASIC prototype For HBD FEE: 40 K on salary + 20K (M&S) - Part of works on done from TPC FEE R&D 1) prototype readout For DCM: 80K on salary + 20K (M&S) R&D on DCM work out readout method for prototype detectors readout Assumptions: we need to 1) readout HBD prototype end of next year 2) readout various prototype detector 1.5 years from now R&D Requests From Nevis C.-Y.Chi, Nevis

C.Woody, Nashville Collaboration Meeting, 6/11/0320 TPC Prototype - Starting Next Year Full size module Tests field cage design Tests materials to be used in actual construction Allows testing with cosmic rays Provides structure on which to design and study readout plane Provides excellent test bench for readout electronics

C.Woody, Nashville Collaboration Meeting, 6/11/0321 R&D Plan FY2003 Complete TPC drift cell and begin comprehensive gas studies Test new 3M GEM foils Continue to improve TPC field cage calculation Begin TPC prototype design Measure CsI quantum efficiencies w/GEMs + radiator gases Measure CF 4 Cherenkov efficiency + scintillation (NSLS) Begin design of HBD & TPC readout electronics Funds: $25K labor + $30K equipment FY2004 Build and test TPC & HBD prototypes Hopefully complete design of HBD readout electronics and continue design of TPC electronics. Start engineering design of TPC/HBD detector system Funds: $200K HBD + $200K TPC

C.Woody, Nashville Collaboration Meeting, 6/11/0322 Extra Slides

C.Woody, Nashville Collaboration Meeting, 6/11/0323 HBD Budget

C.Woody, Nashville Collaboration Meeting, 6/11/0324 R&D Proposal Budget Request PHENIX Institutional Involvement HBD BNL, WIS, Stony Brook TPC BNL (Physics, Instrumentation), Tokyo, FIT Electronics BNL Instrumentation, Columbia (Nevis) Related R&D Efforts STAR (joint effort) LEGS TPC TPC w/GEM readout for NLC/TESLA

C.Woody, Nashville Collaboration Meeting, 6/11/0325 Upgrade Budget and Timeline

C.Woody, Nashville Collaboration Meeting, 6/11/0326 Possible Support Structure for HBD/TPC/VTX H.Van Hecke