Timing Property of MCP-PMT for Single Photon DetectionToru IijimaNagoya UniversityContents Studies of MCP-PMT performance in B-field. New developmentSL10 1x4 linear array MCP-PMTTAC-based ASIC (TAC-IC) Using GaAsP photocathode ?NIM A528(2004)763

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MCP-PMTElectron amplification in micro channel (f ~10mm)Fast/small transit time spreadGain saturationB field immunityGeometrical apperture ~ 60% without Al film at MCP-inGain ~O(106) w/ 2-3 stages Possible to make a multi-anode PMT.Channel~400mmf~10mmGood single photon sensitivityApplication to RICH

Ideal for high resolution timing measurement

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Application of MCP-PMTTOP CounterCherenkov ring imaging w/ precise timemeasurement;Measure (X,T) instead of (X,Y)

Require Photodetection withTTS

Studies of MCP-PMT HPK6 BINP8 HPK10 Burle25HPK6BINP8HPK10Burle25We studied basic performance in B-fieldWith single-anode MCP-PMTs (Burle25 has 2x2 anodes)R&D by Nagoya-U. N-lab.NIM A528(2004)763

MCP-PMTHPK6R3809U-50-11XBINP8N4428HPK10R3809U-50-25XBurle2585011-501PMT size(mm)4530.55271x71Effective size(mm)11182550x50Channel diam.(mm)681025Distances (mm)2.1/0.03/1.00.2/0.09/1.21.1/0.03/0.946.1/0/5.2L/D ratio40404340Bias angle (deg.)1351210Max. H.V.(V)3600320036002500photo-cathodemulti-alkalimulti-alkalimulti-alkalibi-alkaliQ.E.(%) (l=408nm)26182624

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MeasurementMeasured itemsPulse response: Gain, ResolutionTime responseB-filed dependence:

Basic Performance (w/o B-field)Pulse shapeFast raise time (~500ps)Broad shape for BINP8Due to mismatch with H.V. supply dividerNo influence for time resolution

ADC/TDC spectrum for single photon irradiation

ADCHPK6HV=3400VTDC(time walk corrected).25ps/countTail componentdue to bouncingpe at MCP surface

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Gain vs B-fieldSmall chanel diam. Shows high stability against B-field.HPK6 and BINP8 have G>106 in B=1.5TGain increase at B=0.5~1.0T and f 0B=0smaller Deff

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Pulse Height ResolutionPhoton counting in B=0/1.5THPK6, BINP8 exhibit resolution is better in B=1.5T than 0T.Better gain saturation w/ B-field Excellent performance for HPK6 and BINP8(w/ slight off-axis from B).B=0TB=1.5T (0.8T for Burle25)More localized amplificationwith higher B.

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Time response(for single photon)TTS v.s. B-fieldSmall channel diameter shows high stability and good resolution.

TTS v.s. GainFor several HV and B-field conditions30~40ps resolution was obtained for gain>106

Hole size need

SL10 MCP-PMTUnder development in collaboration with Hamamatsu Co.4ch linear array for the TOP counter application.cathode to MCP-in =2mmMCP-out to anode = 1mmUnder developmentUnder development

Photo cathodemulti-alkali#MCP stage2Gain (HV)2x106 (-3.5KV)MCP hole dia.10mmGeometrical C.E.50%#pixel /size1x4 / 5mmx22mmEff. area (2cmT)77%

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SL10 Basic Performance(for single photon)Confirmed gain > 106 and TTS = 30ps(s)In B=1.5T magnetic field.

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Pulse Height Uniformity/Cross TalkMulti-photon irradiation ( ~5)Cross talk (by charge spreading)

Uniformity in Time Responsex (mm)y (mm)Sufficient uniformity in transit time and its resolutionx (mm)y (mm)354540505560

MCP-PMT Issues Cross talkInduced by a neighboring hit(ch-ch coupling).Resolution become worsewhen > 2hits on a PMT(s~30ps 70-90ps)LifetimeAl protection layer helps but collection eff. drops (x60%)How about in B-field?Depend on photocathode?cf) ~700mC/cm2 if TOP used in Super-Belle.Need more studies

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R&D for Readout ASICTime-to-Analog Converter Time resolution

TAC-IC StatusTest production at VDEC (U.Tokyo)1st batch chip Accommodate 3 typesC.F.D + TACL.E.D. + TACTAC onlyWork w/ 40MHz clocking.Resolution being measured.

2nd batch chip being submitted.Some debuggingAim at higher clocking rate.INPUT @ overlap of 2 gatesV1V2

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Using GaAsP photocathode?Sensitive in longer wavelength Quartz: less chromatic error Aerogel: more transparentQE as high as 40% at peak compensate Npe loss due to 1/l2 dep.

Aerogel transmissionNpe x2 possible(from rough estimation)

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Time Resolution with GaAsPTest TTS of a MCP-PMT w/ GaASPTTS may be worse due to thicker photo cathode GaAsP:mm multi(bi)-alkali:100Test w/ a single anode PMTs have been tested.

Same time responsehas been observed.

SL10 w/ GaAsP ??(under consideration)

Structure of measured MCP-PMTMCP channel diameter6m# of MCP2 stageanodesingle anode effective area11mm

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SummaryMCP-PMT w/ 106TTS < 35ps (s)Unresolved issues: cross talk + Life time

New development are underway at Belle1x4 linear array MCP-PMT TOP counter.Basic performance has been confirmed.TAC-based ASIC for high resol. time decoding.

GaAsP photocathode ?TTS

Backup Slides

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TTS vs B-field

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Gain vs HVHPK6BINP10HPK10Burle25HPK6 3 10 (B = 1.5T, H.V= 3.6kV) BINP10 3 10 (B = 1.5T, H.V= 3.2V)HPK10 2 10 (B = 1.5T, H.V= 3.4kV) Burle25 4 10 (B = 0.8T, H.V= 2.5V)6655GainHV(kV)

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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 clarifyLife.Dark countsCost ?HPK Data

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