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A conceptional design of SOLID-TOF. Outline: Development of low resistive glass and high rate RPC Experience in MRPC mass production Conceptional design of SOLID-TOF Conclusions. Wang Yi Department of Engineering Physics Tsinghua University. Introduction of MRPC. High electric field
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A conceptional design of SOLID-TOF • Outline: • Development of low resistive glass and high rate RPC • Experience in MRPC mass production • Conceptional design of SOLID-TOF • Conclusions Wang Yi Department of Engineering Physics Tsinghua University
Introduction of MRPC High electric field ~100kV/cm high drift velocity ~220m/ns high Townsend coefficient Operate in avalanche mode Gas: Freon (electron affinity) iso-butane (UV photon absorption) SF6 (streamer suppressing) Small gap: 0.2-0.3mm, high resolution Multi-gaps: high efficiency Large area, high granularity Good time resolution<100ps High efficiency> 95% Low cost Was used or will be used in ALICE, STAR, FOPI, HADES HARP, CBM, Jlab and NICA-MPD
TOF with different rate capability • Low rate TOF • rate <1kHz/cm2, such as ALICE, STAR, FOPI, HADES and MPD • MRPC with float glass with resistivity ~1012cm • High rate TOF • rate >1kHz/cm2 • ─ CBM ~20kHz/cm2 in center • ─ Jlab ~10kHz/cm2 • ─ Others • MRPC with low resistive glass with resistivity ~1010cm
Performance of low resistivity glass Specifications: Maximal dimension: 50cm×50cm Bulk resistivity: ~1010.cm Standard thickness: 0.5mm--2mm Thickness uniformity: 0.02mm Dielectric constant: ~9 Surface roughness: <10nm DC measurement: very stable Scanned image of glass Thickness distribution 5
Performance test of glass • Resistivity decreases with temperature • Resistivity is very stable in DC measurement This glass was applied with 1000V for about 32days, integrated charge: 1 C/cm2 --roughly corresponding to the CBM life-time over 5 years operation at the maximum particle rate. 6
Prototype of high rate MRPC (pad-readout) + - FEE 2 cm 2 cm Colloidal graphite: 2M / Gas gap:10×0.22mm Glass: 0.78mm,1mm resistivity: ~1010Ω.cm 13 cm
Cosmic ray test Cosmic ray test: Time resolution: ~80ps Efficiency: >95% 8 8
Test results by proton beam @GSI When the particle flux increases every 5 kHz/cm2, the efficiency decreases by 1% and the time resolution deteriorates by 4 ps. Efficiency and time resolution as a function of high voltage at a rate of about 800Hz/cm2 In this test, T0 is about 70ps, the time resolution is deteriorated. 9 9
Beam Test @Rossendorf • Source: 30MeV electron • Trigger: S1^S2^S3^S4^S6^RF • Beam size: 7cm2 • MRPC and S6 are placed on movable columns. • S6: 35mm*35mm*5mm • Reference time: RF signal from ElBE • CAEN TDC 1290 N: 24.5 ps/bin • QDC: V965: 25 fc/bin • Efficiency is determined by the scaler. • Gas: 85% Freon+5% Iso+ 10%SF6 10 10 10
HV scan of pad MRPC • Time resolution: 45ps • Efficiency: 97% 11 11 11
Rate scan of pad MRPC • Rate: >30kHz/cm2 • Time resolution: <60ps • Efficiency: >90% 12 12 12
Time resolution of all pads (1) 10 kHz/cm2 Time resolution (ps) (T0 is subtracted) 60 44 59 43 57 40 65 50 73 60 62 47 42 58 36 54 46 62 77 66 63 48 51 65 Intrinsic time resolution (The jitter of T0, FEE and TD are all subtracted) 13 13
Time resolution of all pads (2) 50 kHz/cm2 Time resolution (ps) 60 72 62 74 54 68 71 58 79 70 68 79 61 73 61 73 68 79 80 90 78 67 81 70 Good uniformity Intrinsic time resolution (ps) 14 14
Prototype of high rate MRPC (strip-readout) Colloidal graphite: 2M / Gas gap: 10×0.25mm Glass: 0.78mm,1mm resistivity: ~1010Ω.cm 15 15
HV scan of strip MRPC (Rosendorf) • Time resolution: 45ps • Efficiency: 97% Working voltage: 6.45 kV 16 16 16
Rate scan of strip MRPC • Rate: >30kHz/cm2 • Time resolution: <60ps • Efficiency: >90% 17 17 17
"or" eff 100 strip1 strip2 80 strip3 "and" eff 60 Efficiency(%) 40 20 0 -20 -10 0 10 20 30 40 Rpcy(mm) Position Scan MRPC#3 3 2 1 Rpcy MRPC#4 18
MRPC workshop @ Tsinghua 20 20
2007 2008 2006 1/2 3/4 5/6 7/8 11/12 1/2 3/4 5/6 7/8 1/2 3/4 5/6 7/8 11/12 9/10 9/10 Prod Start 132 MRPCs 768 MRPCs 1856 MRPCs 2944 MRPCs 4032 MRPCs MRPC production scheme for STAR MRPC production was finished in September of 2008. In Tsinghua: 3100 MRPC have been produced; 2951 Modules passed QA, yield >95% ; 2840 modules shipped to UT Austin . Great success! 21
TOF PID of STAR-TOF PID capability: /k ~1.6 GeV/c, (,k)/p ~ 3.0 GeV/c Observation of Anti-Helium Nature Vol 473,(2011) 353-356 22
R&D and production of STAR-MTD 2011 2012 Plan 1/2 3/4 5/6 7/8 9/10 11/12 1/2 3/4 5/6 11/12 7/8 9/10 Start 20 LMRPCs 40 LMRPCs 60 LMRPCs 80 LMRPCs 100 LMRPCs 115 LMRPCs
Requirement for TOF • /k separation up to 2.5GeV/c • ─ assume 9m path-length: (20:1 kaon rejection at 2.5GeV/c) • ─ High rate MRPC • ─ <80ps • ─ Rate capability>30kHz/cm2 • ─ Estimated rates: 10kHz/cm2 • ─ Active area: 10m2 • ─ Granularity: A~32—63cm2
TOF Design- MRPC Module • Structure of one module • Low resistive glass • 10×0.25mm gaps • 11 strips • strip width: 25mm • interval: 3mm • differential readout This module will be tested with cosmic ray and beam! 27
TOF structure SMnumber:50 Each SM contain 3 modules Each module consists of 11 strips Strip width:25mm Interval:3mm Shortest strip:13cm Longest strip:25cm Total electronic channels:3300 Gas box 28 28
TOF electronics • Fast preamplifier: • Maxim3760 (RICE Univ.) • Ninos TOT (ALICE) • Padi TOT (GSI) • CAD TOT(Tsinghua) • QDC (CAEN, 25fC/bin) • TDC • HPTDC (ALICE, 25ps/ch) • GET4 (GSI, 25ps/ch) • FPGA TDC (?) • DAQ 29
CAD: Current Amplifier and Discriminator 1:N M1 M2 Current Amp iout iin NM0 0is Cin Vout ith PM0 1.52mm Current Disc. 1.52mm Fully Current Mode Simple, Compact and Less power consumption 30
Key parameters *1: for current pulse with 0.3ns rise time, 1-2ns FWHM, and 0.3ns fall time *2: for square current pulse with 200ps width *3: for 200mA input current *4: for 100mA input current 31
A solution for TOF system IN+ FPGA TDC IN- MRPC Ethernet CAD ASIC DAQ Board FEE Board Digitizer Board MRPC technology will be used to construct TOF. Combine ASIC FEE and FPGA TDC and Ethernet DAQ s 32 32
Conclusions • Development of low resistive glass with resistivity ~ 1010Ωcm, very good performance. • Development of pad- and strip- readout high rate MRPCs, rate capability>25kHz/cm2, time resolution<60ps. The glass and detector is adopted by CBM to construct TOF. • Conceptional design of SOLID-TOF. • It can also be use in other experiments such as NICA-MPD.