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GEM based TRD R&D Progress report

Zhangbu Xu (BNL)Ming Shao (USTC/China)

1. Physics Simulations and eSTAR Letter of Intent2. Funding support from NSF China starting 20143. Regular GEM R&D4. Manpower and plans

2Ernst Sichtermann reported to the STAR council in 09/19/2013

6. October 2013: submitted to BNL

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eSTAR Baseline Detector Configuration

Fig.3.2 https://drupal.star.bnl.gov/STAR/node/27990

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eSTAR Kinematic Coverage

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

𝜎 𝑟=𝑑2𝜎

𝑑𝑥𝑑𝑄2

𝑥𝑄4

2𝜋𝛼2 [1+(1−𝑦 )2]=𝐹2 (𝑥 ,𝑄2 )− 𝑦

1+(1− 𝑦 )2𝐹 L (𝑥 ,𝑄2 )

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Detector Acceptance and Resolution

Coverage Orientation Tracking EMC HCAL Resolution (momentum or energy)

-4<<-2 Electron Beam direction;

EAST

BSO E/E=2%/E0.75%

-2<<-1 iTPC+GTRD+ETOF

p/p=1/(pT/pZ-1/6) (0.45%pT0.3%) (pZ/pT) 0.2%/p/

-1<<1 Middle Rapidity

 

TPC+TOF

SMD+EMC E/E=14%/E2%

p/p=0.45%pT0.3% 0.2%/p/

1<<1.7  

Hadron Beam direction;

WEST

iTPC+TOF p/p=1/(pT/pZ-1/4) (0.45%pT0.3%) (pZ/pT) 0.2%/p/

iTPC+FTS SMD+EMC E/E=16%/E2% 1<<2

FTS W-fiber EMC  

HCAL

E/E=12%/E1.4%

E/E=38%/E3%

2.5<<5

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Resolution and Capability

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Semi-inclusive Measurements

Azimuthal correlations in di-hadron (semi-inclusive deep-inelastic scattering) measurements,

e + Aue’ + Au + h1 + h2 + 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.

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Fig.2.6 Why not flow, flux tube and multiplicity dependence? – E. Shuryak

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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

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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 TRDnew TRD

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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.

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Large size GEM construction

Active area: 30*30 cm2

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)

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Prototype Construction

Detector base plane GEM foil with NS2 frame

NS2 frame

Finished detector

-- Ming Shao (USTC)

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Detector test

HV test

Low Pass Filter

Test setup

HV Detector Coppershield

rail

X-ray source & support

X-ray source & support

GasDetector 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)

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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)

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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

g/e

h/e

pT (GeV/c)

Impact at high eta (-2>>-4)1. Kinematic values mainly from crystal calorimeter2. Charged hadron background rejection vs photon conversion background3. Current available detector R&D and simulation efforts4. Current configuration as baseline, welcome new efforts

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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 goals1. Extend eta coverage2. Increase dE/dx resolution3. Increase low-pt coverage4. Reduce material in fiducial

volume <~10% X0readout electronics along the TPC wheels

Currently up to 30% X0 behind TPC sector

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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—October2. New fund for effort3. Proposed joint

MTD/TRD postdoc (50/50%) Offer in process

4. Beam test delay 5. Change of positions

and responsibilities6. Visa delay (student,

professor)