1. Tracking Issues in the Central Region Craig Woody BNL DC Upgrade Meeting August 11, 2002

2. C.Woody, DC Upgrades Meeting, 8/11/042  PHENIX would benefit greatly by implementing a tracking system inside the central magnet: Improved momentum resolution Reduced background from decays and conversions Improved vertex tracking capabilities when used in conjunction with the VTX Improved pattern recognition when used in conjunction with the HBD  We would also benefit greatly by expanding our tracking coverage beyond the present PHENIX acceptance in both   and f. This is particularly important if we want to study jets and do g -jet correlations.  The problem is with implementing a tracking system that will cover h ~ 1 due to the limited space for all detectors in the central region. General Comments

3. C.Woody, DC Upgrades Meeting, 8/11/043 h=1.17 h=0.88 h=0.70 h=0.35 Central Region Planar GEM Tracking chambers Provides tracking coverage over -2.6 < h < 2.6 h = 2.6 Space for the TPC is being squeezed by the need to bring out services for the VTX and the need for space for the readout electronics 10-15 cm

4. C.Woody, DC Upgrades Meeting, 8/11/044 Nose Cone Calorimeter Tracking in front of the NCC would provide clean separation of charged and neutral showers Missing rapidity coverage NCC ~ 1 m dia Area ~ 0.8 m 2 2 detectors x 2 sides  GEM area = 4 x 0.8m 2 =3.2 m 2 Two barrel detectors would add ~ 10m 2 Total GEM area for HBD ~ 1 m 2 Would also provide tracking in a region of rapidity not presently covered in PHENIX E.Kistenev

5. C.Woody, DC Upgrades Meeting, 8/11/045 COMPASS GEM Detectors COMPASS tracking system includes a set of 20 triple GEM detectors (31x31 cm 2 ) each 2D readout using Microstrips Problems with occupancy for PHENIX ? We may want to use a “Micropad” readout similar to what is being proposed for the Forward Silicon Position resolution comparable to Si detectors s ~ 46 m m

6. C.Woody, DC Upgrades Meeting, 8/11/046  STAR is planning to implement a large (~ 10m 2 ) GEM tracking system in their forward direction.  There is a world-wide problem in obtaining GEM foils from CERN due to their limited production capacity (large demand from LHC-B may limit world supply for the foreseeable future)  We (PHENIX/BNL) have been collaborating with CERN, MIT and Yale on developing a new commercial source of GEM detectors (Tech Etch in Plymouth, MA)  MIT has also been developing a GEM readout system based on the COMPASS readout chip. STAR/MIT GEM Development

7. C.Woody, DC Upgrades Meeting, 8/11/047 Comparison of CERN, 3M and Tech Etch Foils Measurements taken w/ Fe-55 source Field config. DG: 0.4kV/cm TG 1: 2.5kV/cm TG 2: 3.0kV/cm IG: 3.5kV/cm B.Azmoun

8. C.Woody, DC Upgrades Meeting, 8/11/048 Gain Stability of GEM Foils Gain instability appears to be a charging effect in the foils due to materials or process used by different manufacturers B.Azmoun

9. C.Woody, DC Upgrades Meeting, 8/11/049 Comparison of Tech Etch and CERN Foils

10. C.Woody, DC Upgrades Meeting, 8/11/0410 APV25 Readout Chip Developed for CMS Silicon strip detector Used by COMPASS for reading out GEMs Bernd Surrow / MIT

11. C.Woody, DC Upgrades Meeting, 8/11/0411  STAR is planning to install a set of three small (10x10 cm 2 ) triple GEM tracking detectors in their forward region possibly as early as Run 5 with a complete readout system based on the APV25 chip (future plans are for a large, 10 m 2 system)  Is a system like this of interest to PHENIX ?  Can we provide enough space in the central region to implement a large acceptance tracking system (either with a TPC or with a system of planar GEM tracking detectors) along with all of the other detectors (and their services) that are planned to go into this region ?  If we’re interested in this, we need to start doing some serious simulation work on how such a tracking system would perform. Future Steps ?