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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. List of Topics. GEM measurements with Ar/CO 2 and CF 4 Status of new GEM foils Gas transmission measurements
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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
List of Topics • GEM measurements with Ar/CO2 and CF4 • 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, 6/11/03
GEM configuration Initial tests with GEMs using CF4 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, 6/11/03
GEM Measurements with Ar/CO2 Resistive divider Fix VTG Vary VF BNL WIS • We seem to get higher gain at the • same voltage than WIS • At fixed VTG the gain curve is nicely • exponential as expected up to ~ 105 • where discharging starts to occur • Varying VTG at fixed VF has a much • weaker effect on gain, but shows no • plateau up to the maximum V Fix VF Vary VTG C.Woody, Nashville Collaboration Meeting, 6/11/03
GEM Measurements with CF4 Resistive divider Fix VTG Vary VF BNL WIS • We again seem to get higher gain at • the same voltage than WIS • Both BNL and WIS see saturation in • CF4 at gain ~ 105 (before breakdown • point) • VTG again has a much weaker effect • on gain and shows no plateau Fix VF Vary VTG C.Woody, Nashville Collaboration Meeting, 6/11/03
New GEM Foils from 3M 3M Microinterconnect Systems Division, Austin, TX In collaboration with Univ. Chicago (J.Collar) hep-ex / 0304013 (April 2003) Roll-to-roll process Limited to 12” width Expecting delivery of 50 new 10x10 cm foils at BNL in ~ 2 weeks C.Woody, Nashville Collaboration Meeting, 6/11/03
Testing Small 3M Foils 80 mm (55 mm) holes spaced in a hexagonal pattern with 140 mm pitch Visually looks to be excellent quality 3 stage GEM with three 1” dia. 3M foils Will compare with CERN foils in Ar/CO2 & CF4 C.Woody, Nashville Collaboration Meeting, 6/11/03
VUV Transparency of Potential Radiator Gases Tranmittance of Argon and CF4 B.Azmoun Gas system being developed and tested in collaboration with LEGS VUV transparency is extremely sensitive to O2 and H2O content C.Woody, Nashville Collaboration Meeting, 6/11/03
Low O2 and H2O levels are critical for good VUV transparency Water Vapor. Oxygen. Ref.: Zaidel’ & Shreider, VUV Spectroscopy C.Woody, Nashville Collaboration Meeting, 6/11/03
Absolute Quantum Efficiency of CsI photocathodes Comparison of our CsI photocathodes with a calibrated CsI PMT VUV Spectrometer CsI PMT Stack with Au coated GEM foil for depositing CsI photocathode Good quality CsI photocathodes are now being made at Stony Brook C.Woody, Nashville Collaboration Meeting, 6/11/03
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 ? N.Smirnov Autocad geometry MAXWELL Not so easy…. Also try 2D calculation using GARFIELD C.Woody, Nashville Collaboration Meeting, 6/11/03
Drift Field Distortions EZ / <EZ> ER / <ER> R GARFIELDMAXWELL N.Smirnov Drift field distortions are generally < 1% C.Woody, Nashville Collaboration Meeting, 6/11/03
Electric Field Distortions Near the HBD N.Smirnov 0 V ED, V/cm 3 mm 5 cm + 75 V wire plane with 5 mm step 30 cm -36 kV 0 V mini TPC field cage wires Initial indications are that the electric field distortions in the region of the HBD are small, but we need to do more calculations ER, V/cm C.Woody, Nashville Collaboration Meeting, 6/11/03
Tracking Issues Need to begin serious simulation work on pattern recognition, track finding and track fitting using tracking information from allPHENIX detectors (present and future - VTX and TPC) ++ Configuration B = 9 KG 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 PT tracks and provides good stand alone tracking for tracks presently outside the PHENIX acceptance (useful for jet measurements) Momentum resolution for various combinations of the VTX and TPC V. Rykov C.Woody, Nashville Collaboration Meeting, 6/11/03
Is this PHENIX or STAR ? Investigating TPC pattern recognition software from LBL (LC) and STAR (Level 3) J.Mitchell’s event display of the PHENIX TPC for a central Au-Au event (PISA simulation) C.Woody, Nashville Collaboration Meeting, 6/11/03
Readout Electronics 55Fe source with 10x10 cm2 triple GEM FADC readout (10 ns bins) Digital scope trace Currently reading out GEM TPC with 100 MHz FADC (SIS 3300 8 channel, 12 bit VME module) pDAQ courtesy of M.Purschke C.Woody, Nashville Collaboration Meeting, 6/11/03
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 65 MHz FADC available soon 32 ch preamp/shaper for APD readout 0.18 mm CMOS, 125 mW per chip Final ASIC 4.3 x 1.6 mm2 C.Woody, Nashville Collaboration Meeting, 6/11/03
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) 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. This is to understand power + readout + packing density issues This will also serve as preliminary study for the HBD readout… C.-Y.Chi, Nevis
R&D Requests From Nevis Assumptions: we need to 1) readout HBD prototype end of next year 2) readout various prototype detector 1.5 years from now 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 C.-Y.Chi, Nevis
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, 6/11/03
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 CF4 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, 6/11/03
Extra Slides C.Woody, Nashville Collaboration Meeting, 6/11/03
HBD Budget C.Woody, Nashville Collaboration Meeting, 6/11/03
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, 6/11/03
Upgrade Budget and Timeline C.Woody, Nashville Collaboration Meeting, 6/11/03
Possible Support Structure for HBD/TPC/VTX H.Van Hecke C.Woody, Nashville Collaboration Meeting, 6/11/03