1. 1 GEM based TRD R&D Progress report Zhangbu Xu (BNL) Ming Shao (USTC/China) 1.Physics Simulations and eSTAR Letter of Intent 2.Funding support from NSF China starting 2014 3.Regular GEM R&D 4.Manpower and plans

2. 2 Ernst Sichtermann reported to the STAR council in 09/19/2013 6. October 2013: submitted to BNL

3. 3 eSTAR Baseline Detector Configuration Fig.3.2 https://drupal.star.bnl.gov/STAR/node/27990

4. 4 eSTAR Kinematic Coverage Figure 3.1: DIS kinematics of scattered electrons and jets with STAR existing detector coverage.

5. 5 Detector Acceptance and Resolution Coverage Orientation TrackingEMCHCALResolution (momentum or energy) -4<<-2 Electron Beam direction; EAST BSO  E /E=2%/E0.75% -2<<-1 iTPC+GTRD +ETOF  p /p=1/(p T /p Z -1/6) (0.45%p T 0.3%) (p Z /p T ) 0.2%/p/ -1<<1 Middle Rapidity TPC+TOF SMD+EMC  E /E=14%/E2%  p /p=0.45%p T 0.3% 0.2%/p/ 1<<1.7 Hadron Beam direction; WEST iTPC+TOF  p /p=1/(p T /p Z -1/4) (0.45%p T 0.3%) (p Z /p T ) 0.2%/p/ iTPC+FTSSMD+EMC  E /E=16%/E2% 1<<2 FTSW-fiber EMC HCAL  E /E=12%/E1.4%  E /E=38%/E3% 2.5<<5

6. 6 Resolution and Capability

7. 7 Semi-inclusive Measurements Azimuthal correlations in di-hadron (semi-inclusive deep-inelastic scattering) measurements, e + Au  e’ + Au + h 1 + h 2 + X provide sensitivity to gluons and have been proposed as a robust probe of saturation: eSTAR projections for 10 GeV electrons scattering off 100 GeV/nucleon Au beams, 1 fb -1. 6 Fig.2.6 Why not flow, flux tube and multiplicity dependence? – E. Shuryak

8. 8 Exclusive Vector Meson Production Mesons such as  or ρ, which have large wave functions, are anticipated to be considerably more sensitive to the saturation effect. eSTAR advantanges: t resolution (2.5%) low-momentum PID around mid-rapidity TRD+iTPC

9. 9 On-going R&D Projects  iTPC Design reduce material and padrow arrange  Forward Calorimeter System (FCS) W-power+Fiber  Crystal Calorimeter (BSO) new crystal  GEM based TRD new TRD

10. 10 eSTAR Executive Summary  In this Letter of Intent, the STAR collaboration proposes a path to evolve STAR into a major experiment, referred to as eSTAR, at a possible future Electron-Ion Collider (EIC) at Brookhaven National Laboratory, eRHIC.  We demonstrate through simulations that eSTAR will deliver on a broad range of key measurements: inclusive structure functions in (polarized) electron-nucleon and electron nucleus scattering, semi-inclusive observables that have one or more identified particles in the current fragmentation region and dihadron correlations in the low-x regime, exclusive observables in deeply-virtual Compton scattering and in vector meson production processes, including diffractive processes. These measurements have been identified as flagship science cases in the recent EIC community white-paper for the eRHIC facility specifications envisioned in the charge for this LOI.  The baseline eSTAR plan has three essential upgrade projects for the scientific program: Endcap TOF, GTRD, CEMC  eSTAR will rely on a replacement upgrade of iTPC and on a subsequent forward upgrades (FCS and FTS) for completing of STAR’s high-priority programs at RHIC  The majority of the collaboration is strongly supportive of the eSTAR effort and multiple institutions are already actively engaged in simulations and R&D for each of the envisioned upgrade projects.  The detector configuration presented in this Letter of Intent represents the baseline instrument. New collaborators from the broader community are vitally important. Science-driven proposals to further strengthen the baseline eSTAR scientific capabilities and program, are particularly welcome.

11. 11 Large size GEM construction  Active area: 30*30 cm 2  Triple layer standard GEM foils from CERN  New stretching method – NS2, easy repair and replace of the GEM foils Explore in more detail the tradeoffs between the TGEM approach and using more traditional foil-based GEMS instead. As a material G-10 remains a bit of a wild card particularly in large areas. -- Committee Q#3,4 -- Ming Shao (USTC)

12. 12 Prototype Construction Detector base planeGEM foil with NS2 frame NS2 frame Finished detector -- Ming Shao (USTC)

13. 13 Detector test HV test Low Pass Filter Test setup HVDetector Copper shield rail X-ray source & support Gas Detector base plane (rear) Thinned spot GEM detector radiated by a Copper k-edge X-ray source through the thinned spot on the base PCB -- Ming Shao (USTC)

14. 14 Test Results MCA recorded spectrum Uniformity: energy resolution ~ 20- 25% (ok) gas gain ~100% larger near the edge than in the central (not good) Over-stretching? 2nd version with improved NS2 design Under further improving ~15-18% -- Ming Shao (USTC)

15. 15 Committee Report (Q#1) On page 25 a new small angle “Inner TPC (or other technology?) tracker is shown. This apparently adds ~30% hits to the tracks. The Committee requests more clarification about such small angle tracking. What would be the plan for this? 0.1 1 10  /e h/e p T (GeV/c) Impact at high eta (-2>  >-4) 1. Kinematic values mainly from crystal calorimeter 2. Charged hadron background rejection vs photon conversion background 3. Current available detector R&D and simulation efforts 4. Current configuration as baseline, welcome new efforts

16. 16 Committee report (Q#2) What will be the effect of additional inner sector TPC electronics on the performance of this and other downstream devices? iTPC upgrade goals 1. Extend eta coverage 2. Increase dE/dx resolution 3. Increase low-pt coverage 4. Reduce material in fiducial volume <~10% X0 readout electronics along the TPC wheels Currently up to 30% X0 behind TPC sector

17. 17 Summary and Plan  Accomplishments and Plan  Physics Simulations and LoI  Fund support from NSF China for GEM based TRD  Regular GEM study starts in China  Continue small TRD R&D at BNL postdoc: Prepare for new gas box, test beam different foils simulations  Several Changes since last review: 1. eSTAR document June—October 2. New fund for effort 3. Proposed joint MTD/TRD postdoc (50/50%) Offer in process 4. Beam test delay 5. Change of positions and responsibilities 6. Visa delay (student, professor)