1. 04/11/2008Lijuan Ruan (WWND2008)1 Prototype Performance of Novel Muon Telescope Detector at STAR Outline: Motivation Simulation Intrinsic timing and spatial resolution: Cosmic ray results Beam test results at Fermi-lab Detector performance at STAR Summary Lijuan Ruan (for the STAR Collaboration) (Brookhaven National Laboratory)

2. 04/11/2008Lijuan Ruan (WWND2008)2 The STAR Detector MagnetCoilsCentralTriggerBarrel(CTB)ZCalTimeProjectionChamber(TPC) Year 2000 Barrel EM Cal (BEMC) Silicon Vertex Tracker (SVT) Silicon Strip Detector (SSD) FTPC Endcap EM Cal FPD TOFp, TOFr FPD Year 2001+ PMD Large acceptance: 2  coverage at mid-rapidity Future upgrade: Time of Flight, DAQ1000, Heavy Flavor Tracker, Muon Telescope Detector

3. 04/11/2008Lijuan Ruan (WWND2008)3 Identify and study the properties of matter with partonic degrees of freedom (flavor, color, sound, temperature …) Penetrating probes Bulk probes - “jets” and heavy flavor - v 2  partonic collectivity - spectra at low p T, particle ratios. Electromagnetic probes: - vector meson properties ( ,   e + e - )  chiral symmetry restoration - thermal dileptons and photons  T QGP - quarkonia (J/   e + e - )  color screening Physics Goals at RHIC S. Bass

4. 04/11/2008Lijuan Ruan (WWND2008)4 Muons: Penetrating Probes A large area of muon telescope detector (MTD) at mid-rapidity, allows for the detection of di-muon pairs from QGP thermal radiation, quarkonia, light vector mesons, possible correlations of quarks and gluons as resonances in QGP, and Drell-Yan production single muons from their semi- leptonic decays of heavy flavor hadrons advantages over electrons: no  conversion, much less Dalitz decay contribution, less affected by radiative losses in the detector materials Quarkonium dissociation temperatures – Digal, Karsch, Satz  +  -

5. 04/11/2008Lijuan Ruan (WWND2008)5 Concept of Design A pseudo detector with scintillator covering the whole iron bars and left the gaps in-between uncovered. 1.muon efficiency: 35-45%, pion efficiency: 0.5-1% 2.muon-to-pion enhancement factor: 50-100 3.muon-to-hadron enhancement factor: 100-1000 including track matching, tof and dE/dx 4.dimuon trigger enhancement factor from online trigger: 10-50 (Guoji Lin, DNP06) Detection efficiency p T (GeV) pion muon  This together with DAQ1000 will greatly enhance our capability of J/  and other dilepton program in RHIC II and future QCD Lab

6. 04/11/2008Lijuan Ruan (WWND2008)6 Hadron Rejection at Intermediate p T p T (GeV)  Part of the hits come from the secondary muons from hadron decay. Some can be removed by using distance of closest approach (DCA) to the vertex on the corresponding track. Guoji Lin, DNP06  Pion efficiency is ~0.5%, pion rejection is about 100 at intermediate p T ; Kaons and protons can be rejected by TOF and dE/dx in TPC, hadron rejection is ~300. π+π+ π-π- Detection efficiency ● all hits ○ hits from π p T (GeV)

7. 04/11/2008Lijuan Ruan (WWND2008)7 Novel & Compact Muon Detector for QCDLab Novel and compact -------- Convention timing, position  track segments + fastHits Muon is penetrating probe J/  trigger, separate  +  - states QCDLab (RHIC II, eRHIC) Works with accelerator high luminosity upgrades R & D to address: spatial and time resolution, muon identification capability, trigger capability and hadron rejection power

8. 04/11/2008Lijuan Ruan (WWND2008)8 Cosmic Ray Results: Long-Strip Multi-gap Resistive Plate Chamber Technology Long MRPC Technology with double-end readout HV:  6.3 KV gas mixture: 95% Freon + 5% isobutane time resolution: ~60 ps spatial resolution: ~1cm efficiency: >95% 950 mm 256 mm 25 mm

9. 04/11/2008Lijuan Ruan (WWND2008)9 Fermi Lab Beam Test Setup (T963 May 2-15 2007) TOF1 TOF2 AND Trigger, common start MWPC1 MWPC2 MWPC5 MWPC4 TOF1 252”73” TOF2 72”164” 449” MRPC1&2 GEMs MWPC3 191” 11” 45 3381 TOF3 70” Upper stream Down stream C1, C2 Test the performance of two long MRPC modules under different working conditions. Comprehensive scans on HV, gas mixture, position, beam energy, etc … (T963 spokesman: Zhangbu Xu)

10. 04/11/2008Lijuan Ruan (WWND2008)10 Beam Test Results HV:  6.3 KV gas mixture: 95% Freon + 5% isobutane time resolution: ~60-70 ps spatial resolution: ~0.6-1cm efficiency: >95% consistent with cosmic test results Tsinghua module as trigger Scintillator as trigger USTC

11. 04/11/2008Lijuan Ruan (WWND2008)11 STAR-MTD in Year 2007 iron bars as hadron absorber two scintillator trays as our trigger 403 cm away from TPC center, |  |<0.25 gas: 95% Freon and 5% iso-butane; HV:  6.3 KV MTD Triggered events: 380 K Au+Au events were taken

12. 04/11/2008Lijuan Ruan (WWND2008)12 Performance at STAR MTD hits: matched with real high p T tracks  z distribution has two components: narrow (muon) and broad (hadron) ones spatial resolution (narrow Gaussian) is ~10 cm at p T >2 GeV; hadron rejection: 200-300 time resolution: 300 ps  Improve our electronics with full scale detector STAR Preliminary p T >2 GeV/c STAR Preliminary

13. 04/11/2008Lijuan Ruan (WWND2008)13 Compared to Simulation from data: p T >2 GeV/c,  (  z) of muon: ~10 cm from simulation: p T =2.5 GeV/c,  (  z) of muon: ~9 cm Data and simulation show consistent results p T (GeV/c)  z (cm) muonspions muons

14. 04/11/2008Lijuan Ruan (WWND2008)14 Muon Identification: dE/dx Effect STAR Preliminary n   <-1 STAR Preliminary n   >0 the narrow Gaussian distribution: dominated by muons STAR Preliminary |  z|<20

15. 04/11/2008Lijuan Ruan (WWND2008)15 the narrow Gaussian distribution: dominated by muons Muon Identification: Cut on High Velocity STAR Preliminary 1/  trackhits - 1/  rawhits >0 n   >0 STAR Preliminary

16. 04/11/2008Lijuan Ruan (WWND2008)16 Simulation: Are Muons Primary? From simulation: the hits from pion decay seem not to have a narrow Gaussian distribution in  z further investigation by studying the DCA distribution in data and simulation  + detection efficiency ● all hits ○ hits from π distance between mc hits and projected hits (cm) p T (GeV)

17. 04/11/2008Lijuan Ruan (WWND2008)17 Summary and Future Plan Cosmic and beam tests: intrinsic timing resolution of long MRPC: ~60-70 ps spatial resolution: ~1 cm The prototype of MTD works at STAR in year 2007. We observed: ---- clear narrow muon peak ---- hadron rejection: 200-300 (requiring track matching) ---- spatial resolution: ~10 cm, consistent with simulation ---- time resolution: ~300 ps The possible physics topics to do: electron muon correlation, muon spectra and v 2 in run7 (2007) Au+Au collisions at 200 GeV The plan: analyze the data in run8 (2008) d+Au and p+p collisions

18. 04/11/2008Lijuan Ruan (WWND2008)18 Towards the Future at STAR Current hardware supports at STAR: HV supply for Long-MRPC: 2 channels from TOF Low voltage supply for read-out electronic boards: old TOF Gas system: share with TOF Gas control computer: share with TOF DAQ system: trigger, including DSM and 2 CDB VPD (start time detector): DSM This set up: run 9 at STAR as well; have a plan to install another tray with TOF electronics Towards the future: Collaborators for a proposal of full scale detector Gas, VPD: share with TOF Electronics: similar to TOF HV, LV: similar to TOF Trigger: DSM and QT Boards

19. 04/11/2008Lijuan Ruan (WWND2008)19 Novel & Compact Muon Detector for QCDLab Novel and compact -------- Convention timing, position  track segments + fastHits QCDLab (RHIC II, eRHIC) Works with accelerator high luminosity upgrades Muon is penetrating probe J/  trigger, separate  +  - states; vector meson; thermal dileptons … STAR Preliminary n   >0 STAR Preliminary