TPC HBD R D C Woody N Smirnov B Azmoun

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 q q Status of new GEM foils q Gas transmission measurements q TPC field cage design q Tracking Issues with TPC and VTX q Electronics for the HBD and TPC q R&D plan for next year C. Woody, Nashville Collaboration Meeting, 6/11/03 2

GEM configuration Initial tests with GEMs using CF 4 did not produce usable signals Problem was with electric field in transfer gaps aller gap spacing and higher fields (> 2 k. V/cm) give much higher gain C. Woody, Nashville Collaboration Meeting, 6/11/03 3

GEM Measurements with Ar/CO 2 Resistive divider Fix VTG Vary VF BNL WIS • We seem to get higher gain at the same voltage than WIS Fix VF Vary VTG • At fixed VTG the gain curve is nicely exponential as expected up to ~ 105 where discharging starts to occur C. Woody, Nashville Collaboration Meeting, 6/11/03 4 • Varying VTG at fixed VF has a

GEM Measurements with CF 4 Resistive divider Fix VTG Vary VF BNL WIS Fix VF Vary VTG • We again seem to get higher gain at the same voltage than WIS • Both BNL and WIS see saturation in CF 4 at gain ~ 105 (before breakdown point) C. Woody, Nashville Collaboration Meeting, 6/11/03 5 • VTG again has a much weaker

New GEM Foils from 3 M 3 M 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 10 x 10 cm foils at BNL in ~ 2 weeks C. Woody, Nashville Collaboration Meeting, 6/11/03 6

Testing Small 3 M Foils 80 mm (55 mm) holes spaced in a hexagonal pattern with 140 mm pitch Visually looks to be excellent 3 stage GEM with three 1” dia. 3 M quality foils Will compare with CERN foils in Ar/CO 2 & CF 4 C. Woody, Nashville Collaboration Meeting, 6/11/03 7

VUV Transparency of Potential Radiator Gases Tranmittance of Argon and CF 4 B. Azmoun Gas system being developed VUV transparency is and extremely tested in collaboration with sensitive to O 2 and H 2 O LEGS C. Woody, Nashville Collaboration Meeting, 6/11/03 8 content

Low O 2 and H 2 O levels are critical for good VUV transparency Water Vapor. Ref. : Zaidel’ & Shreider, VUV Spectroscopy C. Woody, Nashville Collaboration Meeting, 6/11/03 Oxygen. 9

Absolute Quantum Efficiency of Cs. I photocathodes VUV Spectrometer Comparison of our Cs. I photocathodes with a calibrated Cs. I PMT Stack with Au coated GEM foil for depositing Cs. I photocathod e Good quality Cs. I photocathodes are now being made at Stony Brook C. Woody, Nashville Collaboration Meeting, 6/11/03 10

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 2 D calculation using GARFIELD C. Woody, Nashville Collaboration Meeting, 6/11/03 11

Drift Field Distortions EZ / <EZ> ER / <ER> R GARFIELD MAXWELL N. Smirnov Drift field distortions are generally < 1% C. Woody, Nashville Collaboration Meeting, 6/11/03 12

Electric Field Distortions Near the HBD N. Smirnov 0 V + 75 V 30 cm -36 k. V ED, V/cm 3 mm 5 cm wire plane with 5 mm step 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 C. Woody, Nashville Collaboration Meeting, 6/11/03 ER, V/cm 13

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 TPC would beand TPC) tracking VTX used for not only in the electron pair measurement in conjunction with the HBD, but also as an additional tracking detector in normal field running. ++ Configuration B = 9 KG Helps in rejecting false high PT tracks and provides good stand Momentum resolution for alone tracking for tracks various combinations of the presently outside the PHENIX VTX and TPC V. acceptance (useful for jet Rykov C. Woody, 14 measurements) Nashville Collaboration Meeting, 6/11/03

Is this PHENIX or STAR ? Investigatin g 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 15

Readout Electronics 55 Fe source with 10 x 10 cm 2 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) p. DAQ courtesy of M. Purschke C. Woody, Nashville Collaboration Meeting, 6/11/03 16

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 m. W per chip Final ASIC 4. 3 x 1. 6 mm 2 C. Woody, Nashville Collaboration Meeting, 6/11/03 17

TPC and HBD electronics TPC FEE: Samples signal every 25 ns for 140 samples. need L 1 delay buffer (160 samples) + 5 events buffers (700 samples) HBD FEE: Need to measure charge and time (~ several ns) L 1 delay buffer + 5 events buffers. R&D: 1) can use the same type of electronics for both HBD and TPC ? ? ? (by fitting ADC samples to get T 0) 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… C. -Y. Chi, Nevis 18

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 : 60 K 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 + 20 K (M&S) - Part of works on done from TPC FEE R&D 1) prototype readout For DCM: 80 K on salary + 20 K (M&S) R&D on DCM work out readout method for prototype detectors readout C. -Y. Chi, Nevis 19

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 20 bench for C. Woody, Nashville Collaboration Meeting, 6/11/03

R&D Plan FY 2003 • Complete TPC drift cell and begin comprehensive gas studies • Test new 3 M GEM foils • Continue to improve TPC field cage calculation • Begin TPC prototype design • Measure Cs. I quantum efficiencies w/GEMs + radiator gases • Measure CF 4 Cherenkov efficiency + scintillation (NSLS) • Begin design of HBD & TPC readout electronics • Funds: $25 K labor + $30 K equipment FY 2004 • 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: $200 K HBD + $200 K TPC C. Woody, Nashville Collaboration Meeting, 6/11/03 21

Extra Slides C. Woody, Nashville Collaboration Meeting, 6/11/03 22

HBD Budget C. Woody, Nashville Collaboration Meeting, 6/11/03 23

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 24

Upgrade Budget and Timeline C. Woody, Nashville Collaboration Meeting, 6/11/03 25

Possible Support Structure for HBD/TPC/VTX H. Van Hecke C. Woody, Nashville Collaboration Meeting, 6/11/03 26