Status and R&D Plans for GEM/TPC Development in PHENIX and STAR

1. Status and R&D Plans for GEM/TPC Development in PHENIX and STAR Craig Woody For the PHENIX Collaboration and Nikolai Smirnov For the STAR Collaboration RHIC Detector Advisor Committee Meeting November 22, 2003

2. Overview of R&D Status • Results from drift cell • Field cage design • Electronics development • Software development • TPC development effort in Japan • FY04 R&D Plans C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

3. Test Drift Cell Drift Stack (presently 30 cm drift) Photodiode Laser Upper fixed source • Used to study • Drift velocities • Drift lengths • Diffusion parameters • Energy loss (dE/dx) • Study impurities • Readout structures • Field cage design Lenses Lens Triple GEM Lower movable source Lab 2-86 in Physics C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

4. Drift Cell Measurements Ar/CO2 (80/20) Ar/C2H6/CF4 (80/10/10) Top 55Fe source DE/E = 22% (FWHM/mean) * Data o Garfield • DriftCell • Magboltz C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

5. Charge Distribution from Drift Cell(top source, 2 mm pad readout) Ar/CO2 (80/20) Ar/CF4 (95/5) s=1.2 mm s=1.7 mm pad number pad number Measured s=1.1 mm s=1.4 mm Simulation (N.Smirnov) pad number pad number C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

6. TPC Field Cage Design Two Methods Autocad geometry  MAXWELL 2D calculation using GARFIELD N.Smirnov • 3 mm electrodes with 2 mm spacing • Inner layer - two sides • Outer layer - one side • Also studied design with open wire top C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

7. Drift Field Distortions ER EZ / <EZ> R Ratio V/cm GARFIELDMAXWELL N.Smirnov Drift field distortions are generally < 1% C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

8. Ion Feedback and Space Charge Distortion of field components in TPC volume Ion Feedback Emax ~ 1.7V/cm Emax ~ 1.4V/cm z r Radial Axial Ion feedback can be kept < 10% 200 GeV Au+Au G ~ 103 Ion feedback 10% r ~ 10-8 C/m3 B. Yu et.al., IEEE Trans. Nucl. Sci. Vol. 50, No. 4. (2003) 836-841 q ~ 2.5 x 10-3 rad Dx ~ 0.5 mm for 40 cm drift C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

9. TPC/HBD readout electronics C-Y.Chi Nevis • High density, low power preamp and shaper (custom ASIC) • Several possible chips available from BNL Instrumentation • but require some modifications • New line of 40-65 MHz, 8-12 bit FADC (TI, AD) • Development by Nevis - will use TI 8 channel 12 bit 40 MHz • for prototype to be built this year (64 channel board w/FPGA) C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

10. PHENIX TPC Tracking Simulation An integrated tracking package using the TPC and VTX inner detectors is currently being developed and implemented into the PHENIX software Event display of the PHENIX TPC for a central Au-Au event (PISA simulation - J.Mitchell) C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

11. Drift region -V Drift 30cm PHENIX TPC R&D in Japan • T.Isobe, K.Ozawa, M.Inuzuka, H.Hamagaki, T. Sakaguchi, F.Kajihara,T.Gunji,N.Kurihara, (CNS Tokyo) • S.Sawada (KEK), S.Yokaichi (RIKEN) Prototype TPC PWC readout, but designed for GEM readout (will test this year) • Beam test at KEK gave: • 100 microns along wire direction • 500 microns along drift direction • 1.5 cm double hit resolution Operated in pure CF4 C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

12. TPC Prototype - To be built in FY04 Full size module Test 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 Test bench for new readout electronics C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

13. R&D motivation (STAR specific) Meet All Physics Goals in “STAR Decadal Plan (Future Physics)” for RHIC pp and AA beams need: • high event statistics • good event selection (trigger) with PID possibility • unique (beam-beam) vertex matching. Requires: • RHIC upgrade up to 40 times design luminosity • experiment upgrade to improve -- data rate (the speed of tracking detectors, DAQ) --trigger performance -- particle identification while reducing detector mass and maintaining the capabilities of the present STAR experiment ( “destroy nothing” approach from STAR Physics Program point of view). C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

14. If STAR is going to be a RHIC II Detector … (long term upgrade) 70 cm 2x55 cm One of the top priorities in STAR is to prepare for the eventual replacement of the STAR TPC with a fast, high luminosity and high resolution tracking set up. The new concept is to develop: • fast, compact TPC using micro-pattern readout, • with an integrated direct imaging Cherenkov detector that can be used for particle tracking and powerful e+/- identification • that will organize together with fast, low mass, not expensive Pad Detectors (on the basis of micro-pattern technology) and Si-detectors the new STAR tracking setup convenient both for relativistic heavy ion and pp- program. 20 cm 55 cm Pad Det. With CsI Photocathode 16 identical modules with 35 pad-rows, double (triple) GEM readout with pad size: 0.2x1. cm². Maximum drift: 40-45 cm. “Working” gas: fast, low diffusion, good UV transparency . C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

15. Improvements from TPC replacement( realistic simulation / reconstruction ) • Solve the problem with Event pile up, Space Charge distortions • Increase Data Rate • Increase “trigger power”; reliable and fast High Pt (jets) trigger • e+/- PID ( 0.05 -5.0 ) GeV/c (additional to dE/dX, ToF, EMC) • Very low Pt particle measurement • Possibility to work with “fast” Detectors only • Realize an “on-line track finding / reconstruction” algorithm using data from Pad Detectors as “pointers” for miniTPC • Use space for new Detectors to be installed C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

16. STAR tracking improvement in the short term both barrel and “forward” directions • How to “struggle” with TPC space charge problem? • Additional tracking / calibration Detectors in front of TPC, and (may be) a good reason is to use one ToF slat for the coordinate Detector behind TPC • Additional tracking a front of EEMC. • “Forward Physics” at STAR (?!) C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

17. Additional tracking / calibration detectors in STAR based on micro-pattern technology (GEM) Tracking detector in front of EEMC TPC field cage SVT GEM Detectors behind TPC; ( one ToF slat ?) SSD GEM Detectors in front of TPC Beam pipe C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

18. Additional tracking in 1<|η|<2 direction (pp  W+/-  e+/- + X)(with STAR Vertex Detector and TPC FEE Upgrades);new team(s) in STAR, B.Surrow (MIT) is a leader GEM Detectors 2-3 additional layers of Si Detectors C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03

19. R&D Plan • FY2004 • Study fast drift gases using drift cell • Complete design of field cage and readout plane for TPC • Build and test TPC prototype module • Build first prototype of readout electronics • Start engineering design of TPC detector in PHENIX • Continue software development in tracking and simulations • Build and install in several GEM Pad Detectors in STAR Longer term plans • Develop a commercial source of GEM foils • Develop a GEM foil testing and calibration facility (at Yale or MIT ?) Micro-pattern Detectors are critical for today’s experiments and for the future C.Woody/N.Smirnov, RHIC Detector Advisory Committee Meeting, 11/22/03