GEM based TRD R&D Progress report

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

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

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

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

5. Detector Acceptance and Resolution

6. Resolution and Capability

7. Semi-inclusiveMeasurements Azimuthal correlations indi-hadron(semi-inclusivedeep-inelasticscattering) measurements, e+Aue’+ Au+h1+h2+X providesensitivity to gluonsandhavebeenproposedasarobustprobeof saturation: Fig.2.6 Why not flow, flux tube and multiplicity dependence? – E. Shuryak eSTARprojections for 10GeVelectronsscattering off 100GeV/nucleonAubeams,1 fb-1.

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

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

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. Active area: 30*30 cm2 Triple layer standard GEM foils from CERN New stretching method – NS2, easy repair and replace of the GEM foils Large size GEM construction 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. Prototype Construction Detector base plane GEM foil with NS2 frame NS2 frame Finished detector -- Ming Shao (USTC)

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

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

15. Committee Report (Q#1) 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 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? g/e h/e 0.1 1 10 pT (GeV/c)

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 • Extend eta coverage • Increase dE/dx resolution • Increase low-pt coverage • Reduce material in fiducial volume <~10% X0readout electronics along the TPC wheels Currently up to 30% X0 behind TPC sector

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: • eSTAR document June—October • New fund for effort • Proposed joint MTD/TRD postdoc (50/50%) Offer in process • Beam test delay • Change of positions and responsibilities • Visa delay (student, professor)