2004/11/30RICH04 Workshop 1 Timing Property of MCP-PMT for Single Photon Detection Toru Iijima Nagoya University Contents Studies of MCP-PMT performance in B-field. New development SL10 1x4 linear array MCP-PMT TAC-based ASIC (TAC-IC) Using GaAsP photocathode ? NIM A528(2004)763

RICH04 Workshop2 2004/11/30 MCP-PMT Electron amplification in micro channel (  ~10  m)  Fast/small transit time spread  Gain saturation  B field immunity Geometrical apperture ~ 60% ※ without Al film at MCP-in Gain ~O(10 6 ) w/ 2-3 stages Possible to make a multi-anode PMT. Channel ~400  m  ~10  m Good single photon sensitivity Application to RICH Ideal for high resolution timing measurement

RICH04 Workshop3 2004/11/30 Application of MCP-PMT TOP Counter  Cherenkov ring imaging w/ precise time measurement;  Measure (X,T) instead of (X,Y) Require Photodetection with  TTS<100ps   X~5mm  B up to 1.5T High Resolution TOF  Use Cherenkov light (~0 decay time)  Minimum dispersion in light propagation. KK Simulated (X,T) image NIM A453(2000)331 Tile-TOF test counter Talk by Super-B WS (Hawaii, Jan. 2004) IEEE04 NSS (Rome, Oct. 2004) cf): Focusing-DIRC J.Va’vra Aerogel-RICH A.Gorisek

RICH04 Workshop4 2004/11/30 Studies of MCP-PMT HPK6 BINP8 HPK10 Burle25 MCP-PMTHPK6 R3809U-50-11X BINP8 N4428 HPK10 R3809U-50-25X Burle PMT size(mm) x71 Effective size(mm) x50 Channel diam.(  m) Distances (mm)2.1/0.03/1.00.2/0.09/1.21.1/0.03/ /0/5.2 L/D ratio Bias angle (deg.) Max. H.V. (V) photo-cathodemulti-alkali bi-alkali Q.E.(%) ( =408nm) HPK6 BINP8 HPK10 Burle25 We studied basic performance in B-field With single-anode MCP-PMTs (Burle25 has 2x2 anodes) R&D by Nagoya-U. N-lab. NIM A528(2004)763

RICH04 Workshop5 2004/11/30 Measurement Measured items  Pulse response: Gain, Resolution  Time response  B-filed dependence: <1.5 Tesla, B-axis angles Setup  Hamamatsu PLP02 405nm Pulse width 34ps (jitter<10ps)  C5594 amplifier Gain = 36dB Freq. Band = 50kHz – 1.5GHz  CAMAC ADC, TDC(25ps/count)  Phillips 708 discriminator PMT-axis B-field 

RICH04 Workshop6 2004/11/30 Basic Performance (w/o B-field) Pulse shape  Fast raise time (~500ps)  Broad shape for BINP8 Due to mismatch with H.V. supply divider No influence for time resolution ADC/TDC spectrum for single photon irradiation ADC HPK6 HV=3400V TDC (time walk corrected). 25ps/count Tail component due to bouncing pe at MCP surface

RICH04 Workshop7 2004/11/30 Gain vs B-field Small chanel diam. Shows high stability against B-field. HPK6 and BINP8 have G>10 6 in B=1.5T Gain increase at B=0.5~1.0T and  <~ 45deg. G=exp(A x  )  = L/D B>0 B=0 smaller D eff

RICH04 Workshop8 2004/11/30 Pulse Height Resolution Photon counting in B=0/1.5T HPK6, 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). HPK6 BINP8 HPK10 Burle25 B=0T B=1.5T (0.8T for Burle25) B=0T B=1.5T More localized amplification with higher B. 1p.e 2p.e 3p.e HPK6 at B=1.5T (0deg.) BINP8 at B=1.5T (15deg.)

RICH04 Workshop9 2004/11/30 Time response (for single photon) TTS v.s. B-field  Small channel diameter shows high stability and good resolution. TTS v.s. Gain  For several HV and B-field conditions  30~40ps resolution was obtained for gain>10 6 Hole size need <~10  m  to get time resolution of ~30ps under 1.5T B-field. Single photon Burle25 HPK10 BINP8 HPK6 Burle25 HPK10 BINP8 HPK6

RICH04 Workshop /11/30 SL10 MCP-PMT Under development in collaboration with Hamamatsu Co. 4ch linear array for the TOP counter application. Photo cathodemulti-alkali #MCP stage2 Gain (HV)2x10 6 (-3.5KV) MCP hole dia. 10  m Geometrical C.E.50% #pixel /size1x4 / 5mmx22mm Eff. area (2cm T )77% cathode to MCP-in =2mm MCP-out to anode = 1mm Under development

RICH04 Workshop /11/30 SL10 Basic Performance (for single photon) Confirmed gain > 10 6 and TTS = 30ps(  ) In B=1.5T magnetic field. B = 0 T Gain = 2x10 6 B = 0 T  = 30ps

RICH04 Workshop /11/30 Pulse Height Uniformity/Cross Talk Multi-photon irradiation ( ~5) Scan across the 4ch. (0.1mm step) 1234 Relative ADC mean (%) ch1 ch2 ch3 ch4 5.3mm all>75% x (mm) 5.3mm >90% for most region Scan top half of ch-2. (Step: X 0.1mm, Y 1mm) y (mm) x (mm) Cross talk (by charge spreading) <0.3% Sufficient uniformity in gain and efficiency. Small enough cross talk.

RICH04 Workshop /11/30 Uniformity in Time Response x (mm) y (mm) Sufficient uniformity in transit time and its resolution x (mm) y (mm) <43psec for most region <50psec for most region Scan top half of CH2 w/ single photon TDC # of event  mean Time resolution ( , psec) Time variation (  mean, psec)

RICH04 Workshop /11/30 MCP-PMT Issues Cross talk  Induced by a neighboring hit (ch-ch coupling).  Resolution become worse when > 2hits on a PMT (s~30ps  70-90ps) Lifetime  Al protection layer helps but collection eff. drops (x60%)  How about in B-field?  Depend on photocathode? cf) ~700mC/cm 2 if TOP used in Super-Belle. Need more studies…

RICH04 Workshop /11/30 R&D for Readout ASIC Time-to-Analog Converter  Time resolution <~20ps. Double overlap gates  Less dead time (~100ns)  CMOS process. H.Nakano, T.Iijima (Nagoya) H.Ikeda, I.Adachi, S.Nishida (KEK) T.Sumiyoshi (TMU) 40MHz CLOCK INPUT GATE1 GATE2 AOUT1 AOUT2 75ps 125ps T1 T2 V1 = K x T1 V2 = K x T2 “TAC-IC” Concept

RICH04 Workshop /11/30 ③ ② ① TAC-IC Status Test production at VDEC (U.Tokyo) 1 st batch chip  Accommodate 3 types  C.F.D + TAC  L.E.D. + TAC  TAC only  Work w/ 40MHz clocking.  Resolution being measured. 2 nd batch chip being submitted.  Some debugging  Aim at higher clocking rate. overlap of 2 gates V1 V2

RICH04 Workshop /11/30 Using GaAsP photocathode? Sensitive in longer wavelength  Quartz: less chromatic error  Aerogel: more transparent QE as high as 40% at peak  compensate N pe loss due to 1/ 2 dep. Light propagation velocity inside quartz Aerogel transmission Npe x2 possible (from rough estimation)

RICH04 Workshop /11/30 Time Resolution with GaAsP Test TTS of a MCP-PMT w/ GaASP  TTS may be worse due to thicker photo cathode GaAsP: ～  m ⇔ multi(bi)-alkali: ～ 100 Å  Test w/ a single anode PMTs have been tested. Same time response has been observed. SL10 w/ GaAsP ?? (under consideration) Structure of measured MCP-PMT MCP channel diameterφ6μm # of MCP2 stage anodesingle anode effective areaφ11mm

RICH04 Workshop /11/30 Summary MCP-PMT w/ <10  m channel has excellent single photon counting performance up to 1.5 T magnetic field.  Gain > 10 6  TTS < 35ps (  )  Unresolved issues: cross talk + Life time New development are underway at Belle  1x4 linear array MCP-PMT  TOP counter. Basic performance has been confirmed.  TAC-based ASIC for high resol. time decoding. GaAsP photocathode ?  TTS <35ps has been confirmed.  Worth for consideration. Some samples exhibits very sharp HPD like single photon peak (better in B field) Stay tuned !

RICH04 Workshop /11/30 Backup Slides

RICH04 Workshop /11/30 TTS vs B-field

RICH04 Workshop /11/30 Gain vs HV HPK 6 BINP1 0 HPK1 0 Burle2 5 HPK6  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) Gain HV(kV)

RICH04 Workshop /11/30 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