eSTAR Upgrade Ming Shao USTC

eRHIC – the future of RHIC STAR Regional Meeting, Weihai, /24/2012

ToF: π, K identification, t 0, electron ECal: electrons and photons GCT: a compact tracker with enhanced electron capability - Combine high-threshold (gas) Cherenkov with TPC(-like) tracking HCal: W powder, spaghetti calorimeter Simulations ahead eSTAR task force formed Evolving from STAR into eSTAR proton/nucleus electron ToF TPC i.s. GCT HCal GEM disks ECal 3STAR Regional Meeting, Weihai, 20127/24/2012

eRHIC phase 1: kinematic range “Forward” (-2.5 <~ η < -1) electron acceptance essential to span deep-inelastic (DIS) regime Both backward and forward hadron coverage valuable for semi-inclusive deep-inelastic (SIDIS) scattering 4 5 GeV e + 50 GeV/nucleon TPC+ BEMC+TOF Missing today EEMC+FGT DIS region SIDIS region 5 GeV e GeV/nucleon STAR Regional Meeting, Weihai, 20127/24/2012

Hadron rejection Clean electron identification (e-ID) over large phase space coverage needed 5STAR Regional Meeting, Weihai, 20127/24/2012

Proven at STAR mid-rapidity With velocity cut from TOF Within <70cm space inside endcap TOF as start-time for BTOF and MTD TOF + dE/dx for electron ID TOF for hadron PID Extended tracking with precise points High-precision dE/dx (Xe+CO 2 ) TRD An Endcap TOF & TRD for Identifying Electrons (ETTIE) Recoil electron tagging in ep collision 6STAR Regional Meeting, Weihai, 20127/24/2012

GEANT4 Simulation on TRD Physics List: QGSP_BERT as baseline TR process only applied to specific detectors (TRD) Primary Track: electron/pion at 1- 5 GeV/c Magnetic field: uniform solenoid field B=0.5T 7STAR Regional Meeting, Weihai, 2012 Similar to ALICE TRD, 3 layers due to limited space 7/24/2012

e/h Rejection ( Likelihood) 8 Construct Likelihood according to the total energy deposited and the position of largest energy deposition, in N(=3) TR layers STAR Regional Meeting, Weihai, 20127/24/2012

ETTIE in STAR Simulation 9 Geometry (AgML) g2t hit, track, volume (Geant) St_geant_Maker (Geant to McEvent) StMcEvent, StEvent and related classes All ETTIE components (TRD + TOF + Absorber/Scintillator) in Only TPC and ETTIE sub-system are shown STAR Regional Meeting, Weihai, 20127/24/2012

TPC and TRD Hits Simulated by STARSIM pT = 2 GeV/c Eta range: (-1.7, -1.4) Phi = 0 degree Vertex (0,0,0) Thin TRD Readout board (2mm) muon electron 10STAR Regional Meeting, Weihai, 20127/24/2012

TPC resolution and track fitting 11 tpc/perf/hiterrors Use Helix to fit hits (MCS and dE/dx effects not included) TPC hit spatial resolution from parameterization Primary vertex constrain applied (X-Y 100 microns, Z 2cm electrons MCS and dE/dx effect significant muons STAR Regional Meeting, Weihai, 20127/24/2012

Scan on pseudo-rapidity 12 FEE, Readout, cooling, and part of mechanical structure removed muonselectrons Need material suppression to improve electron momentum resolution iTPC will help For -1>  >-1.4, pT resolution by TPC alone is good enough -> TRD may be coarse readout? STAR Regional Meeting, Weihai, 20127/24/2012

TRD hits resolution: X-Y 100 microns, Z 300 microns TRD Spatial Resolution Impact TRD hits resolution: X-Y 300 microns, Z 500 microns muons electrons 13STAR Regional Meeting, Weihai, 20127/24/2012

TRD hits per layer: 30 TRD Efficiency Impact muons electrons TRD hits per layer: 15 (50% efficiency) muonselectrons 14STAR Regional Meeting, Weihai, 20127/24/2012

TRD tracking with Stv First attempt succeeds with preliminary detector (TRD) response simulation – StEtrFastSimMaker – by Victor Stv track finding – Along Z direction (along r direction in TPC) – With Detector geometry and materials in (Kalman Filter) 15  ~ -1.2 p T = 1GeV/c 10 MC tracks Primary vertex loosely bounded Efficiency low (~30%) – iTPC? p T resolution ~4% STAR Regional Meeting, Weihai, 20127/24/2012

GEM based TRD – R&D work with Xe+CO 2 better position resolution by GEM better rate capacity / space charge Need R&D – TRD readout structure – thin/thick GEM? – Multiple time bin readout – TRD gain in Xe/CO 2 and uniformity – GEM long time stability ALICE TRDReadout: MWPC -> GEM Multiple time bin readout Globe etching (micro etching) New type thick GEM 0.2mm 0.5mm 16STAR Regional Meeting, Weihai, 20127/24/2012

Simulation - Pythia in STARSIM Preliminary estimation of the acceptance of eSTAR detector system Pythia parameter setting follows EIC- MC guide, ic/index.php/PYTHIA, w/o radiative correction. ic/index.php/PYTHIA Stand-alone Pythia events for consistency check 17 Pythia version 6.4 STAR Regional Meeting, Weihai, 20127/24/2012

eSTAR acceptance 18 TRD #hit>0TPC #hit>0 && TOF #hit>0 STAR Regional Meeting, Weihai, 20127/24/2012

STAR Regional Meeting, Weihai, TPC acceptance (with iTPC upgrade) 7/24/2012

STAR Regional Meeting, Weihai, TPC acceptance (with iTPC upgrade) 7/24/2012

Summary ETTIE geometry implemented in STAR, TRD hits can be generated (in geant) and recorded (in StMcEvent and StEvent). TPC sector material budget has significant impact on track fitting (TPC+TRD), especially for inner sector part TRD spatial resolution change from 100 microns to 300 microns, or efficiency change to 50%, seem to have no significant impact on track fitting – need further check with MCS and energy loss effects included Stv tracking with TRD hits is accomplished. Still need further improvement. Recoil electron (x,Q2) acceptance in ep GeV collisions in eSTAR system evaluated. 21STAR Regional Meeting, Weihai, 20127/24/2012

Kinematics in DIS at EIC 22STAR Regional Meeting, Weihai, 20127/24/2012

STAR Regional Meeting, Weihai, eRHIC phase-I 7/24/2012

eRHIC phase-II STAR Regional Meeting, Weihai, /24/2012

Some distributions 25STAR Regional Meeting, Weihai, 20127/24/2012

TR Simulation Check 26 More energy deposited near radiator TR changes energy deposition significantly Incident particle kinetic energy: 3GeV STAR Regional Meeting, Weihai, 20127/24/2012

Energy deposition at 1-5 GeV 27 electronpion Energy deposition increase with particle energy, according to relativistic dE/dx rise Energy deposition increase with particle energy within 1-3 GeV due to increase of TR photons, then saturate at 3-5 GeV STAR Regional Meeting, Weihai, 20127/24/2012

28 Tracking cut on energy deposition Tracking cut: exclude hits far away from the expected track trajectory Suppressing the tail of energy deposition (from eg. knock-on electrons or secondaries from hadron process) STAR Regional Meeting, Weihai, 20127/24/2012

Materials at TPC Endcap Change eta from to -1.23, avoiding the supporting Al rib pT resolution 2.9%pT resolution 4.4% STAR Regional Meeting, Weihai, 20127/24/2012