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Status of R&D on a TPC/HBD for PHENIX

Status of R&D on a TPC/HBD for PHENIX. Craig Woody BNL. DC Upgrades Meeting December 12, 2001. Tracking in the Central Region in PHENIX. PHENIX ± Field Configuration. Momentum resolution in TPC 300 m m single point resolution in x,y,z (Simulation by N. Smirnoff). d p T /p T =0.02.

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Status of R&D on a TPC/HBD for PHENIX

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  1. Status of R&D on a TPC/HBD for PHENIX Craig Woody BNL DC Upgrades Meeting December 12, 2001

  2. C.Woody, DC Upgrades Meeting,12/14/01

  3. Tracking in the Central Region in PHENIX PHENIX ± Field Configuration Momentum resolution in TPC 300 mm single point resolution in x,y,z (Simulation by N. Smirnoff) dpT/pT=0.02 Field Integral Z (m) C.Woody, DC Upgrades Meeting,12/14/01

  4. R&D Topics • Study the electronic and optical properties of gases (CF4, CH4, …) • Detector design (field cage, readout plane, construct prototype) • Investigate readout detector options (GEM, mMega, MWPC w/pads) • Design of integrated readout electronics • Monte Carlo simulation studies C.Woody, DC Upgrades Meeting,12/14/01

  5. Initial Measurements with a Micromegas at BNL November 2001 I. Giomataris, CEA-Saclay, France G.C.Smith, B. Yu, BNL C.Woody, DC Upgrades Meeting,12/14/01

  6. I.Giomataris,G.Smith,B.Yu Experimental set-up C.Woody, DC Upgrades Meeting,12/14/01

  7. I.Giomataris,G.Smith,B.Yu Micro-photograph of Micromegas 5 m copper, 25 m diameter holes, 50 m pitch 50 m tall Kapton pillar Pillar spacing normally 1mm ( 2mm on test sample) 50 m C.Woody, DC Upgrades Meeting,12/14/01

  8. I.Giomataris,G.Smith,B.Yu Anode plane: Al strips with pitch 0.95 mm Center 12 strips bussed together, to preamplifier. Load  150 pF. Rest of strips grounded for present measurements. 152 mm Active area of micromegas mesh Section used for measurements (12 mm wide by 70mm) 152 mm C.Woody, DC Upgrades Meeting,12/14/01

  9. I.Giomataris,G.Smith,B.Yu Measurement instrumentation Collimator (25 m, 100 m, 1 mm) Monochromator Energized X-ray source Detector C.Woody, DC Upgrades Meeting,12/14/01

  10. Charge and Gain vs HT I.Giomataris,G.Smith,B.Yu C.Woody, DC Upgrades Meeting,12/14/01

  11. I.Giomataris,G.Smith,B.Yu +ve ion transmission C.Woody, DC Upgrades Meeting,12/14/01

  12. I.Giomataris,G.Smith,B.Yu Anode Pulse Height Distribution – Ar / 20% CO2 Linear Scale Energy Resolution = 16% FWHM (Equivalent to 15.3% for 55Fe) Logarithmic Scale Highest amplitude peak? Collimated Cr K , 5.4 keV Gain  1000 C.Woody, DC Upgrades Meeting,12/14/01

  13. I.Giomataris,G.Smith,B.Yu Anode Pulse Height Distribution – CF4 Collimated Cr K , 5.4 keV Gain  300 (Vmicromegas = 570 ) Linear Scale Energy Resolution = 27% FWHM (Equivalent to 26% for 55Fe) C.Woody, DC Upgrades Meeting,12/14/01

  14. I.Giomataris,G.Smith,B.Yu Comments • Micromegas mesh tested in Ar/20%CO2 and pure CF4 • Gas gain ~ 7,000 achieved in Ar/20%CO2 and ~ 300 in CF4 • 2mm post spacing may limit upper voltage, and hence gain, with CF4 • Resn of 16% and 27% FWHM in Ar/20%CO2 and pure CF4 at 5.4 keV • Positive ion feedthrough ~ 1% with ED = 200 V cm-1 • Collimated beam  cyclic gain change (~ 3%) across mesh holes • Tests continue: Ar/10%CH4, Ar/20%DME, ~ 10ns shaping, ion drift velocity, local gain variation, lateral diffusion…. C.Woody, DC Upgrades Meeting,12/14/01

  15. GEM Detector Courtesy of F. Sauli (CERN) Additional GEM foils will be used to construct readout detector for TPC Drift Cell C.Woody, DC Upgrades Meeting,12/14/01

  16. F.Sauli (CERN) Narrow pad response function (Ds ~ 1 mm): GEM TPC Improved multi-track resolution Fast signals (no ion tail) DT~20 ns : F Intrinsic multi-track resolution DV ~ 1 mm3 (Standard MWPC TPC ~ 1 cm3) C.Woody, DC Upgrades Meeting,12/14/01

  17. M.Dixit (Carleton) C.Woody, DC Upgrades Meeting,12/14/01

  18. F.Sauli (CERN) Strong positive ion feedback suppression GEM TPC Negligible effects Electrons Ions S. Bachmann et al, Nucl. Instr. and Meth. A 438(1999)376 With a standard Double GEM, in normal operating conditions (EDRIFT=200 V/cm), the Ion Feedback is ~ 1.5% Improve GEM geometry to reduce FB (---> 10-4?) Gated operation easy! C.Woody, DC Upgrades Meeting,12/14/01

  19. VUV Spectrometer Measures optical transmission down to 120 nm Correlate with drift measurements C.Lu & K.T. McDonald, NIM A343(1994) 135-151. C.Woody, DC Upgrades Meeting,12/14/01

  20. Set up to measure VUV transmission of gases Construct gas cell with MgF2 or LiF2 window Measure transmission of CF4 down to ~ 1150 angstroms Measurements by Bob Azmoun, Stony Brook C.Woody, DC Upgrades Meeting,12/14/01

  21. Monte Carlo Simulations • Detailed TPC/HBD detector Monte Carlo already exists which is being used • to optimize geometry, pad size, etc(N. Smirnoff) • - study two track resolution, multihit resolution, diffusion limits, etc. • - will also run GARFIELD to study field cage configurations • TPC/HBD geometry is now in full PHENIX simulation package PISA (C. Aidala) • Note: New proposed silicon pixel detectors have also been added to PISA; • will use this together with TPC/HBD to study the effect on tracking and • momentum resolution • Studies are currently under way of to study electron pair signals (e.g., r,w,f, • low mass pairs) in heavy ion events using EXODUS Monte Carlo(K. Ozawa) • Next step will be to incorporate all three Monte Carlos programs together • into PISA to do full event simulation of electron pair signals, Dalitz pairs, • conversions and other background sources, combined with studies of tracking • and momentum resolution, using the full PHENIX detector simulation package. C.Woody, DC Upgrades Meeting,12/14/01

  22. e- p TPC e+ p e- p e+ Using the TPC to measure Low Mass Lepton Pairs and Vector Mesons in PHENIX • Operate PHENIX with low inner B field • to optimize measurement of low • momentum tracks • Identify signal electrons (r,w,f, …) and • background electrons with p>200 MeV in • outer PHENIX detectors • Identify low momentum electrons (p<200 • MeV) using dE/dx from TPC and/or • Cherenkov light in HBD • Calculate effective mass between all • opposite sign tracks identified as electrons • (eelectron > 0.9, prej > 1:200) • Reject pair if mass < 140 MeV V0 measured in outer PHENIX detectors (Pe > 200 MeV/c) Must provide sufficient Dalitz rejection (>90%) while preserving the true signal C.Woody, DC Upgrades Meeting,12/14/01

  23. K.Ozawa (U.Tokyo) Signal survival probability • Signal survival rates for several kind of Dalitz rejection ratio were calculated. • Dalitz rejection ratio were calculated as a fraction of Dalitz rejected events on the invariant mass histogram. • It was depends on mass cut parameter. • Calculations were done for Dalitz rejection ratio of 50%, 60%, 70%, 80%, 90%, 95%, and 100%. C.Woody, DC Upgrades Meeting,12/14/01

  24. f J/y Y Results K.Ozawa (U.Tokyo) Results r w Survival probability of f is 70% for dN/dy = 650, when we keep 90% Dalitz rejection ratio. C.Woody, DC Upgrades Meeting,12/14/01

  25. TPC/HBD Detector in PISA CsI Readout Plane 70 cm 20 cm 55 cm 80 cm C.Aidala C.Woody, DC Upgrades Meeting,12/14/01

  26. TPC Detector with HBD Radiator CsI Readout Plane 20 cm Readout Pads DR ~ 1 cm f ~ 2 mm 55 cm 70 cm C.Aidala C.Woody, DC Upgrades Meeting,12/14/01

  27. C.Aidala PISA Simulation EXODUS Event in TPC C.Woody, DC Upgrades Meeting,12/14/01

  28. Electronics Development • Investigate requirements for integrated TPC readout electronics • Assuming pad size of ~ 1.0 x 0.2 cm and an area of 0.8 m2 per readout plane: • 80K channels => 40K channels per readout plane (25 pads/cm2) • Power, cooling, services are a major design consideration • assume 25 mW/ch => 4.0x104 x .025 = 1 kW/plane(not too bad!) • Data volume is high (16 Mb unsuppressed) => need to do zero suppression in FEE • Even with zero suppression, data transfer rate must be high • 160 Gbit/sec => 80 Gbit/side (2-8 Gbit G-links in the future ?) • What will be the cost per channel ? ($40/ch?, STAR: $25/ch) • Hopefully will save in cost/channel by doing highly integrated design • (but then need good estimate of design costs) • Readout requirements for HBD will be different than TPC • May need to operate at higher gain • Channel count will be lower (depending on segmentation) • Electronics will be in the PHENIX acceptance => low mass • Readout must function in the existing PHENIX system readout architecture • Buffer size < 4.0(6.4) msec (5 event buffer) • Readout speed of 40 MHz (40 words/msec) • Readout time < 40 msec (DCM speed = 25kHz) • High luminosity pp running probably requires a level 3 trigger C.Woody, DC Upgrades Meeting,12/14/01

  29. TPC Readout Plane and Electonics P.O’Connor & Bo Yu (BNL) Readout Pads DR ~ 1 cm f ~ 2 mm Segmentation driven largely by resolution C.Woody, DC Upgrades Meeting,12/14/01

  30. Possible TPC Readout Electronics Chain P.O’Connor (BNL) C.Woody, DC Upgrades Meeting,12/14/01

  31. Cost and Schedule Estimate • R&D (2 years) • HBD Detector Design: $250K • TPC Detector Design: $500K • Electronic Design: $1M (5 FTEs x 2 yrs) • Total: $1.75M • Construction (2 years) • Detector: $100K • Gas System: $100 K • Detector mounted electronics: $3.2M • (80K Readout Channels @ $40/ch) • Other readout electronics: $300K • Total: $3.7 M C.Woody, DC Upgrades Meeting,12/14/01

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