1. Preparation of MTD production Yongjie Sun Center of Particle Physics and Technology University of Science and Technology of China

2. Mar. 30, 2011STAR MTD workshop, USTC 2 Outline Introduction Design of MRPC for MTD The first prototype The “ real size ” prototype Facilities for the mass production Summary and outlook

3. Mar. 30, 2011STAR MTD workshop, USTC 3 1. STAR MTD 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, trigger capability in Au+Au Z. Xu, BNL LDRD 07-007; L. Ruan et al., Journal of Physics G: Nucl. Part. Phys. 36 (2009) 095001

4. Mar. 30, 2011STAR MTD workshop, USTC 4 The novel design of MTD Iron bars as absorber Muon ID by combining Track matching with MTD  spatial resolution Energy loss in TPC Time-of-flight measurement  time resolution MRPC as detector Good timing: < 100 ps Spatial resolution: ~ 1 cm Cost-effective for large area coverage

5. Mar. 30, 2011STAR MTD workshop, USTC 5 The success of MRPC for STAR TOF Muon Detector Time resolution <100ps Efficiency  90% High granularity

6. Mar. 30, 2011STAR MTD workshop, USTC 6 The multiplicity of muon tracks is quite low Long strips save electronics channels Read out from two ends Mean time  Eliminate the position along the strip Time difference  Position information Easy to build for large area coverage detector MRPC with Long Strips

7. Mar. 30, 2011STAR MTD workshop, USTC 7 Gas gaps: 10 x 0.25 mm, in 2 stacks Glass plates: 0.71 mm anode 2. Prototype design Size: 950 x 256 mm 2 Read out strip: 25 mm wide, 4 mm gaps between strips Active area: 870 x 170 mm 2 The first prototype was constructed in 2006 at USTC. 1.5 cm

8. Mar. 30, 2011STAR MTD workshop, USTC 8 The considerations in the design 10 gaps: for better timing 2.5 cm wide strips: for better track matching The size: limited by the pcb production technics The edges: sufficient for uniform field and HV protecting.

9. Mar. 30, 2011STAR MTD workshop, USTC 9 Some photos

10. Mar. 30, 2011STAR MTD workshop, USTC 10 Trigger area: 20 x 5 cm 2 Time reference (T0) TOF MRPC was used to get 6 segments along the strip. Gas: 95% Freon + 5% iso-butane HV=±6.4kV LMRPC Cosmic ray test Telescope setup

11. Mar. 30, 2011STAR MTD workshop, USTC 11 Left end ADC SpectrumRight end ADC Spectrum ADC ch Trigger area and ADC spectrum Cosmic ray test Trigger area: 20 x 5 cm 2 STAR TOF MRPC PAD: 3.15 x 6.1 cm 2 Scheme of the trigger

12. Mar. 30, 2011STAR MTD workshop, USTC 12 HV plateau Cosmic ray test

13. Mar. 30, 2011STAR MTD workshop, USTC 13 signal propagation velocity Cosmic ray test TOF MRPC 6 trigger positions along the strip Time difference of 2 ends vs. position V -1 ~59.6±4.9 ps/cm

14. Mar. 30, 2011STAR MTD workshop, USTC 14 center of the strip One end of the strip T-A correlation T-A correction & Time resolution Cosmic ray test

15. Mar. 30, 2011STAR MTD workshop, USTC 15 MWPC5 MWPC1MWPC2 MWPC4 TOF1 252”73” TOF2 72”164” 449” LMRPC GEMs MWPC3 191” 563381 TOF3 70” Upper stream Down stream C1, C2 Beam Energy: 32 GeV FNAL Beam Test (T963) Beam test setup

16. Mar. 30, 2011STAR MTD workshop, USTC 16 Efficiency plateau FNAL Beam Test (T963) Time resolution

17. Mar. 30, 2011STAR MTD workshop, USTC 17 FNAL Beam Test (T963) Using the tracking, we get the signal propagation velocity: ~ 60ps/cm The half time difference of 2 ends of a strip: σ Δ T/2 ~ 1.1 channel (55ps) Spatial resolution: ~ 1 cm Spatial resolution

18. Mar. 30, 2011STAR MTD workshop, USTC 18 Running in STAR Run 7 & Run 8 Run 9 & Run 10

19. Mar. 30, 2011STAR MTD workshop, USTC 19 Run 10 Performance: Time and Spatial Resolution Cosmic ray trigger: Total resolution: 109 ps Start resolution (2 TOF hits): 46 ps Multiple scattering: 25 ps MTD intrinsic resolution: 96 ps System spatial resolution: 2.5 cm, dominated by multiple scattering L. Li, UT Austin σ: 109 ps σ: 2.5 cm pure muons average p T : ~6 GeV/c From Lijuan Ruan ’ s talk at MTD review Sep. 17, 2010

20. Mar. 30, 2011STAR MTD workshop, USTC 20 Run 9 Performance: Time Resolution L. Li, UT Austin σ: 142 ps Include muons from pion, kaon decays and punch-through hadrons Muon average p T : ~2.5 GeV/c Total resolution: 142 ps Start resolution (start detector with TOF electronics readout): 81 ps Multiple scattering: 70 ps MTD intrinsic resolution: 94 ps From Lijuan Ruan ’ s talk at MTD review Sep. 17, 2010

21. Mar. 30, 2011STAR MTD workshop, USTC 21 MTD Concept of Design A detector with long-MRPCs covers the whole iron bars and leave the gaps in- between uncovered. Acceptance: 45% at |  |<0.5 117 modules, 1404 readout strips, 2808 readout channels Long-MRPC detector technology, HPTDC electronics (same as STAR-TOF)

22. Mar. 30, 2011STAR MTD workshop, USTC 22 Prototype of “ real size ”  “ real size ” module: active width ~ 52 cm  12 strips: 3.8 cm wide, 87 cm long, 0.6 cm in between  Single stack: 6(5) × 0.25 mm gaps

23. Mar. 30, 2011STAR MTD workshop, USTC 23 Structure — side view inner glass = 874 Licron electrode = 882 outer glass / honeycomb = 890 PC board = 915 Licron electrode = 551 outer glass / honeycomb = 559 PC board = 580 386 inner glass = 543 Gas gaps: Prototype I: 250μm × 6 Prototype II: 250μm × 5

24. Mar. 30, 2011STAR MTD workshop, USTC 24 HV plateau of Prototype I (6 gaps) The efficiency > 90% @ ±7300 V (Vth=30mV) Time resolution ~ 90 ps without SF 6 SF 6 is helpful for performance enhancement.

25. Mar. 30, 2011STAR MTD workshop, USTC 25 Charge spectrum@ ±7600V With more SF6, less streamer achieved. no SF6 2% SF65% SF6

26. Mar. 30, 2011STAR MTD workshop, USTC 26 Noise rate (Hz/strip) HV= ± 8000V, Vth=30mV (R134a:C 4 H 10 :SF 6 =93:5:2) Strip No. 123456789101112 Left479253407359310274255252321390259346 Right526280326303163235320266377400280313 With HV filter: HV (+/-) 10MΩ 0.5nF LMRPC Equivalent to < 1.5 Hz/cm 2, comparable to TOF MRPC

27. Mar. 30, 2011STAR MTD workshop, USTC 27 Prototype II with 5 gaps Efficiency > 90% @ ± 6300 V Time resolution comparable to Prototype I.

28. Mar. 30, 2011STAR MTD workshop, USTC 28 3. Facilities for mass production The same clean room as for STAR TOF with controlled temperature and humidity. Two new desks for big module construction.

29. Mar. 30, 2011STAR MTD workshop, USTC 29 Electrode production A separate room for glass cleaning and electrode spraying. Clean the glass with hot steam and alcohol. Graphite liquor will be used for painting the electrode.

30. Mar. 30, 2011STAR MTD workshop, USTC 30 Cosmic ray test system A new cosmic ray system has been setup. Trigger: 20 x 5 cm 2 T0: <50 ps 16 TDC + 16 QDC VME based DAQ Gas: Freon + iso-C 4 H 10 + SF 6

31. Mar. 30, 2011STAR MTD workshop, USTC 31 Manpower for production 3 professors, 1 lecturer, 2 pos-doc, 1 engineer and 3 graduate students. 2 technicians for module construction. 1 technician for electrode painting.

32. Mar. 30, 2011STAR MTD workshop, USTC 32 The first Long-strip MRPCs (10-gap) show very good performance and were successfully running at STAR from Run7 to Run10. The cosmic ray test : time resolution: around 70 ps; detection efficiency: higher than 95%. T963 beam test at FNAL: spatial resolution: less than 1 cm. time resolution and detection efficiency similar to cosmic test Performance running at STAR: Time resolution <100ps, spatial resolution ~2.5cm The performances of both “ real size ” LMRPCs are good enough for the MTD requirements. The facilities are ready. Mass production can start soon after the final design is confirmed. 4. Summary Thank You ！

33. Mar. 30, 2011STAR MTD workshop, USTC 33