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Development of RICH Counters for Belle Upgrade

Development of RICH Counters for Belle Upgrade. Toru Iijima Nagoya University. KEKB/Belle Plan Belle PID Upgrade Plan Status of TOP Counter Summary. KEKB/Belle Plan. Super-KEKB +RF, ante-chamber etc. L peak = (3-5) x 10 35 cm -1 s -1.

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Development of RICH Counters for Belle Upgrade

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  1. Development of RICH Counters for Belle Upgrade Toru Iijima Nagoya University • KEKB/Belle Plan • Belle PID Upgrade Plan • Status of TOP Counter • Summary RICH2004 Workshop

  2. KEKB/Belle Plan Super-KEKB +RF, ante-chamber etc. Lpeak = (3-5) x 1035cm-1s-1 Letter-Of-Intent available (KEK-Report 2004-4), Not decided yet Carb cavity (2006) Lpeak = (3-5) x 1034cm-1s-1 Lint = 1ab-1 by 2007? Present Lpeak = 1.4x1034cm-2s-1 Lint = 300+a fb-1 RICH2004 Workshop

  3. Identification of SUSY breaking mechanism if NP=SUSY Study of NP effect in B and t decays time or integrated luminosity Precise test of SM and search for NP Yes!! Super-KEKB/Belle NP discovered at LHC (2010?) Discovery of CPV in B decays Now 300 fb-1 Present KEKB/Belle sin2f1(b) (’04) = 0.73±0.04 for <charmonium> 0.41±0.07 for <bs penguin> 3.8s deviation Physics Objects • Far precise CKM • CPV in bs penguin modes ex. BfKs, h’Ks, Xsg • AFB in BKll, Xsll • Charged Higgs (ex. BDtn) • LFV in t decay (ex. tmg) RICH2004 Workshop

  4. Belle Upgrade Aerogel Cherenkov counter + TOF counter SC solenoid 1.5T g “TOP” + RICH 3.5GeV e+ CsI(Tl) 16X0 g pure CsI (endcap) 8GeV e- Tracking + dE/dx small cell + He/C2H5 g remove inner lyrs. New readout and computing systems Si vtx. det. 3 lyr. DSSD m / KL detection 14/15 lyr. RPC+Fe g 2 pixel lyrs. + 3 lyr. DSSD g tile scintillator RICH2004 Workshop

  5. Particle ID in Belle Calibratiopn by D*+D0p+, D0K-p+ eff.(KK) >90% fake(pK)<10% RICH2004 Workshop

  6. Physics Targets • B  pp/Kp, Dp/DK • B rg/K*g (bdg/sg) • B  K ll, K n n • Full reconstruction • Less systematics for precise measurements Motivation of PID Upgrade • Improve separation for K/p, and also for m/p hopefully. • Extend momentum coverage in the forward endcap. • Endcap-ACC (n=1.03) functions only for flavor tagging • Reduced material thickness, and more homogeneous distribution. • 30% in total = 18% (ACC) + 12% (TOF) • PMTs dominate for ACC • To cope with increasing background. • TOF may not survive • ACC seems to be OK @ x10 background W/ MQT. RICH2004 Workshop

  7. Idea of PID Upgrade • Baseline • Barrel  TOP Counter • Endcap  Aerogel RICH • Other ideas • Focusing DIRC • TOF w/ finer segmentation  co-exist with the present Barrel-ACC to cover high momentum Prototype RICH2004 Workshop

  8. “Focusing” Proximity Focusing Aerogel-RICH • Candidate for the forward endcap. • Proof-of-principle w/ flat panel PMT. • New idea of dual-(multi-) radiator for improvement. • sq = 14.6mr, Npe = 9.1 w/ focusing (n1/n2=1.047/1.057) K/p sep. = 4.8s at 4 GeV/c • Development of 12x12 HAPD +electronics is underway The major remaining issue cf) Talks by P.Krizan, S.Korpar, T.Sumiyoshi, I.Adachi, A.Gorisek n1 n2 n1<n2 “Defocusing” n1 n2 n1>n2 “Multi-radiator” RICH2004 Workshop

  9. TOP or TOP Counter Concept NIM A453(2000)331 • Quartz-based RICH counter to detect internally reflected Cherenkov light (like DIRC at BaBar) • But reconstruct the image in (X,TOP) instead of (X,Y). “TOP” = Time Of Propagation • Possible if DTOP < 100ps for each arriving photon. TOF from IP to quartz bar is also used. RICH2004 Workshop

  10. Simulation 2GeV/c, q=90 deg. “Bar TOP” Counter • Proximity focusing in X measurement • Simplified structure and easier installation. • Loose requirement for DX (~5mm) • Well polished quartz radiator • Photodetection by linear-anode PMT • Flipped images can be resolved by widening the bar width (>20cm). K p d-ray, had. int. RICH2004 Workshop

  11. TOP Counter Design (LoI) 16% x X0 • Quartz radiator: 40cm x 255cm x 2cm  18 segmentation in r-f • Photodetection: MCP-PMT w/ linear anode (5mm) • Good time resolution: < 40ps/photon • Single photon sensitive up to 1.5T • Number of PMTs (channels) • 15 pcs. (60ch) /module • 270 pcs. (1080ch) / total for 1 read-out plane (LoI design) • 810 pcs. (3240cn) / total for 3 read-out planes (present baseline) R=115~125cm Z=-72.5~182.5cm RICH2004 Workshop

  12. Beam Test w/ Prototype Test counter • Demonstration of principle w/ • 1m(L)x20cm(W)x2cm(T) • R5900-00-L16 @ KEK PS p2 line 3 GeV/c p- beam qin=fin=90 degree • Clear ring image • Reasonable • time resolution • Enough bar quality RICH2004 Workshop

  13. Performance of TOP • Separation power in two particle species Single photon resolution Group velocity vg=c/ng(l) Npe RICH2004 Workshop

  14. s(time) measured w/ beam (“Butterfly TOP” w/ R5900-L16) Quartz Radiator Bar#1 • Synthetic fused silica • Long transmission • Good polishability • Radiation hardness • Shin-etsu, “SUPRASIL-P30” • T~90% at l = 250nm • Polishing accuracy at Okamoto Kogaku Co. (Yokohama) Bar#2 Quartz polishing accuracy OK RICH2004 Workshop

  15. Confirmed gain > 106 and TTS = 30ps(s) In B=1.5T magnetic field. ※ Remaining issues: cross talk, life, deadtime etc. MCP-PMT (SL10) Under Development cf) My talk on Tuesday • 1x4 linear-anode MCP-PMT newly developed for TOP readout. RICH2004 Workshop

  16. 4GeV/c,bialkali photocathode Expected Performance (1) Design optimization • Long propagation distance  Large chromatic error. • Read-out at both ends  better performance in q>90deg. • Another read-out at q=46deg.  better performance in q<90deg. Geometrical acceptance loss = 6.3% for 5cm gap. forward forward RICH2004 Workshop

  17. Performance w/ 3 read-out planes • Target: >4s K/p @ 4GeV/c over q=35-135deg. ~2.5sm/p @ 0.6GeV/c DIRC performance (from RICH2002) TOP performance (base design) D* decay events Want improvement to achieve the target ! RICH2004 Workshop

  18. Further reduction of chromatic dispersion → GaAsP photo-cathode Higher Q.E. (~40%@540nm) at longer wave length → less chromatic error Light propagation velocity inside quartz MCP-PMT with GaAsP cf) My talk on Tuesday Photon sensitivity at longer wave length shows the smaller velocity fluctuation. RICH2004 Workshop

  19. Performance with GaAsP • >4s K/p achievable almost everywhere. Measured time response For MCP-PMT w/ GaAsP HPK:R3809UGAAP TDC distribution σ～30ps Input of MC RICH2004 Workshop

  20. Efficiency and fake rate for KID Bialkali photo-cathode option Estimated background rate Based on a simulation w/ spent electron generator (cross checked by the present TOF rate) Dominated by g e+e- conversion g hit rate = 44kHz/counter at L=1034 6.8photons/hit/counter ~900kHz-hit/counter at BG x 20 ~80kHz/ch Stable performanceevenfor 10 times more BG rate of our estimate Robustness against Beam BG (/counter) Our estimate RICH2004 Workshop

  21. Issues cf) My talk on Tuesday • Photodetection by MCP-PMT • Cross talk, lifetime, deadtime • Photocathode selection (bialkali or GaAsP) • Readout electronics (TAC-IC) • Further evaluation of performance • Geant4 based simulation • Reconstruction • Analytic likelihood approach • Multi-track capability, boundary effects… • Beam BG effects • Overall performance for physics processes • Mechanical consideration • Glue joint of 40cm wide quartz bars… RICH2004 Workshop

  22. Summary • For improving the Belle PID performance in future, we are developing RICH counters based on new ideas. • TOP counter for barrel Detect internally reflected Cherenkov light with precise time measurement; (X,T) readout. • Aerogel-RICH for endcap Proximity focusing w/ novel “dual-(multi-) radiator” technique. • Target performance: >4s for the whole B decay region. • Target year for upgrade: 2008-9 • The major remaining issue is photodetection for both • MCP-PMT for TOP • H(A)PD for Aerogel-RICH Many Challenges ! Stay Tuned ! RICH2004 Workshop

  23. Beam Test Results ofMulti-Radiator Aerogel-RICH RICH2004 Workshop

  24. Butterfly TOP Cf) Talk by T.Ohshima at RICH2002 RICH2004 Workshop

  25. cut TOP Simulation • Evaluate TOP performance and optimize design • Located at current TOF position • GEANT base, 1.5T magnetic field • Readout (MCP-PMT) • s~30ps, 5mm ch. width • 80% dead space • QE~25%, CE~50% • Use only 1st arriving hit in each ch. Measured TDC dist. including the tail is used as a response function. Efficiency and fake rate : by log likelihood-ratio Reference design RICH2004 Workshop

  26. cf.) Preset Belle/BaBar Efficiency/fake(LoI design) • Large drop around q=70~80 degree, due to chromaticity. • Need to optimize TOP design (Bar length, width, ch. division, etc.) RICH2004 Workshop

  27. Segmented TOP 3 times more readout But no need for gluing (much easier construction) • For long path length, • DTOP is increased, but • Error due to chromaticity is increased. • Optimal path length should exist. • Segmented TOP • Various version is tested. • For example, RICH2004 Workshop

  28. “Focusing TOP” • 3D information • t, x and vertical angle • Focusing block attached to forward edge. • Matrix readout For example, • 1cm x 2mm size with 0.5mm dead space • MCP-PMT (TTS~40ps) at x=0cm Similar concept to “Ultimate FDIRC” by B.Ratcliff, NIM A502(2003) 211 RICH2004 Workshop

  29. Fake/Efficiency w/ Focusing • Very good separation (= ultimate performance)! • Require additional development of • Photodetectors w/ matrix anode ~10mm(X) x ~2mm(Y) • High density high resolution timing readout O(105) 98% 2% RICH2004 Workshop

  30. Multi-anode MCP-PMT w/ GaAsP ? • The timing performance has been checked with single channel MCP-PMT sample. • According to HPK, • Can be made. • Effecive area ratio (cathode area/package) may be smaller. • Need clarify • Life. • Dark counts • Cost ? HPK Data RICH2004 Workshop

  31. H.Nakano, T.Iijima (Nagoya) H.Ikeda, I.Adachi, S.Nishida (KEK) T.Sumiyoshi (TMU) INPUT 125ps GATE1 T1 75ps GATE2 T2 AOUT1 V1 = K x T1 V2 = K x T2 AOUT2 R&D for Readout ASIC • Time-to-Analog Converter  Time resolution <~20ps. • Double overlap gates  Less dead time (~100ns). • 0.35m CMOS process. “TAC-IC” Concept 40MHz CLOCK RICH2004 Workshop

  32. cf) Talk by A.Drutskoy At Hawaii WS Focusing DIRC RICH2004 Workshop

  33. 50ps TOF • Finer segmentation • faster electronics to cope with the increasing rate. RICH2004 Workshop

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