Timing Property of MCPPMT for Single Photon Detection

Timing Property of MCP-PMT for Single Photon Detection Toru Iijima Nagoya University Contents n Studies of MCP-PMT performance in B-field. n New development SL 10 1 x 4 linear array MCP-PMT TAC-based ASIC (TAC-IC) n Using Ga. As. P photocathode ? 2004/11/30 RICH 04 Workshop NIM A 528(2004)763 1

Channel ~400 mm MCP-PMT n n Electron amplification in micro channel (f ~10 mm) ¨ Fast/small transit time spread ¨ Gain saturation ¨ B field immunity Geometrical apperture ~ 60% f~10 mm ※ without Al film at MCP-in n n Gain ~O(106) w/ 2 -3 stages Possible to make a multi-anode PMT. Good single photon sensitivity Application to RICH Ideal for high resolution timing measurement 2004/11/30 RICH 04 Workshop 2

Application of MCP-PMT n TOP Counter K p NIM A 453(2000)331 Cherenkov ring imaging w/ precise time measurement; ¨ Measure (X, T) instead of (X, Y) ¨ Simulated (X, T) image Require Photodetection with TTS<100 ps ¨ DX~5 mm ¨ B up to 1. 5 T ¨ n High Resolution TOF Talk by K. Inami @ 　 Super-B WS (Hawaii, Jan. 2004) IEEE 04 NSS (Rome, Oct. 2004) Use Cherenkov light (~0 decay time) ¨ Minimum dispersion in light propagation. ¨ cf): Focusing-DIRC J. Va’vra Aerogel-RICH A. Gorisek RICH 04 Workshop 2004/11/30 Tile-TOF test counter 3

Studies of MCP-PMT We studied basic performance in B-field With single-anode MCP-PMTs (Burle 25 has 2 x 2 anodes) R&D by Nagoya-U. N-lab. NIM A 528(2004)763 HPK 6 MCP-PMT HPK 6 BINP 8 R 3809 U-50 -11 X BINP 8 HPK 10 N 4428 HPK 6 BINP 8 HPK 10 Burle 25 R 3809 U-50 -25 X 85011 -501 PMT size(mm) 45 30. 5 52 71 x 71 Effective size(mm) 11 18 25 50 x 50 Channel diam. (mm) 6 8 10 25 Distances (mm) 2. 1/0. 03/1. 0 0. 2/0. 09/1. 2 1. 1/0. 03/0. 94 6. 1/0/5. 2 L/D ratio 40 40 43 40 Bias angle (deg. ) 13 5 12 10 Max. H. V. (V) 3600 3200 3600 2500 photo-cathode multi-alkali bi-alkali Q. E. (%) (l=408 nm) 2004/11/30 26 RICH 04 Workshop 18 26 24 4

B-field Measurement n f PMT-axis Measured items Pulse response: Gain, Resolution ¨ Time response ¨ B-filed dependence: <1. 5 Tesla, B-axis angles ¨ n Setup ¨ Hamamatsu PLP 02 n n ¨ 405 nm Pulse width 34 ps (jitter<10 ps) C 5594 amplifier n n Gain = 36 d. B Freq. Band = 50 k. Hz – 1. 5 GHz CAMAC ADC, TDC(25 ps/count) ¨ Phillips 708 discriminator ¨ 2004/11/30 RICH 04 Workshop 5

Basic Performance (w/o B-field) n Pulse shape Fast raise time (~500 ps) ¨ Broad shape for BINP 8 ¨ n n n Due to mismatch with H. V. supply divider No influence for time resolution ADC/TDC spectrum for single photon irradiation TDC Tail component (time walk corrected). due to bouncing ADC pe at MCP surface HPK 6 HV=3400 V 2004/11/30 RICH 04 Workshop 25 ps/count 6

Gain increase at B=0. 5~1. 0 T and f <~ 45 deg. Gain vs B-field G=exp(A x a) a = L/D B=0 B>0 smaller Deff n n Small chanel diam. Shows high stability against B-field. HPK 6 and BINP 8 have G>106 in B=1. 5 T 2004/11/30 RICH 04 Workshop 7

Pulse Height Resolution n Photon counting in B=0/1. 5 T HPK 6, BINP 8 exhibit resolution is better in B=1. 5 T than 0 T. Better gain saturation w/ B-field HPK 6(0 deg. ) HPK 6 at B=1. 5 T B=0 T BINP 8 B=1. 5 T (0. 8 T for Burle 25) at B=1. 5 T (15 deg. ) More localized amplification with higher B. 1 p. e 2 p. e HPK 10 Burle 25 3 p. e B=0 T B=1. 5 T Excellent performance for HPK 6 and BINP 8(w/ slight off-axis from B). 2004/11/30 RICH 04 Workshop 8

Single photon Time response (for single photon) n TTS v. s. B-field ¨ n Burle 25 HPK 10 BINP 8 Small channel diameter shows high stability and good resolution. HPK 6 TTS v. s. Gain For several HV and B-field conditions ¨ 30~40 ps resolution was obtained for gain>106 ¨ Burle 25 BINP 8 n Hole size need <~10 mm ¨ HPK 10 to get time resolution of ~30 ps under 1. 5 T B-field. 2004/11/30 Single photon RICH 04 Workshop HPK 6 9

lo pm ev e d er nd n Under development in collaboration with Hamamatsu Co. 4 ch linear array for the TOP counter application. U n en t SL 10 MCP-PMT cathode to MCP-in =2 mm MCP-out to anode = 1 mm multi-alkali #MCP stage 2 Gain (HV) 2 x 106 (-3. 5 KV) MCP hole dia. 10 mm Geometrical C. E. 50% #pixel /size 1 x 4 / 5 mmx 22 mm Eff. area (2 cm. T) 77% 2004/11/30 U nd er d ev el op m en t Photo cathode RICH 04 Workshop 10

SL 10 Basic Performance (for single photon) B = 0 T Gain = 2 x 106 2004/11/30 B = 0 T s = 30 ps Confirmed gain > 106 and TTS = 30 ps(s) In B=1. 5 T magnetic field. RICH 04 Workshop 11

Pulse Height Uniformity/Cross Talk Relative ADC mean (%) 120 5. 3 mm ch 1 ch 2 ch 3 y (mm) Scan top half of ch-2. (Step: X 0. 1 mm, Y 1 mm) 5. 3 mm Scan across the 4 ch. 1 2 3 4 (0. 1 mm step) 160 Multi-photon irradiation (<Npe> ~5) 12 34 90 ch 4 80 all>75% 40 >90% for most region. 0 0 5 10 15 20 x (mm) Cross talk (by charge spreading) <0. 3% 2004/11/30 n. Sufficient uniformity in gain and efficiency. n. Small enough cross talk. RICH 04 Workshop 12

Scan top half of CH 2 w/ single photon 1 2 3 4 60 Time resolution (s, psec) # of event Uniformity in Time Response mean TDC s 500 Time variation (Dmean, psec) y (mm) 55 50 45 <43 psec for most region 40 40 400 300 200 100 <50 psec for most region 50 35 x (mm) Sufficient uniformity in transit time and its resolution 2004/11/30 RICH 04 Workshop 13 0

MCP-PMT Issues n Cross talk Induced by a neighboring hit (ch-ch coupling). ¨ Resolution become worse when > 2 hits on a PMT (s~30 ps 70 -90 ps) ¨ n Lifetime p p p Al protection layer helps but collection eff. drops (x 60%) How about in B-field? Depend on photocathode? cf) ~700 m. C/cm 2 if TOP used in Super-Belle. 2004/11/30 Need more studies… RICH 04 Workshop 14

R&D for Readout ASIC n n n H. Nakano, T. Iijima (Nagoya) H. Ikeda, I. Adachi, S. Nishida (KEK) T. Sumiyoshi (TMU) Time-to-Analog Converter Time resolution <~20 ps. Double overlap gates Less dead time (~100 ns). 0. 35 m CMOS process. “TAC-IC” Concept INPUT 125 ps GATE 1 T 1 75 ps GATE 2 T 2 AOUT 1 V 1 = K x T 1 V 2 = K x T 2 AOUT 2 40 MHz CLOCK 2004/11/30 RICH 04 Workshop 15

① ② TAC-IC Status n n Test production at VDEC (U. Tokyo) ③ 1 st batch chip ¨ Accommodate 3 types ① C. F. D + TAC ② L. E. D. + TAC ③ TAC only INPUT @ overlap of 2 gates Work w/ 40 MHz clocking. ¨ Resolution being measured. ¨ n 2 nd batch chip being submitted. Some debugging ¨ Aim at higher clocking rate. ¨ 2004/11/30 RICH 04 Workshop V 2 V 1 16

Using Ga. As. P photocathode? n n Sensitive in longer wavelength Quartz: less chromatic error Aerogel: more transparent QE as high as 40% at peak Light propagation velocity inside quartz compensate Npe loss due to 1/l 2 dep. Aerogel transmission Npe x 2 possible (from rough estimation) 2004/11/30 RICH 04 Workshop 17

Time Resolution with Ga. As. P n Test TTS of a MCP-PMT w/ Ga. ASP TTS may be worse due to thicker photo cathode Ga. As. P: ～mm ⇔ multi(bi)-alkali: ～ 100Å ¨ Test w/ a single anode PMTs have been tested. ¨ Structure of measured MCP-PMT MCP channel diameter φ6μm # of MCP anode effective area 2 stage single anode φ11 mm Same time response has been observed. SL 10 w/ Ga. As. P ? ? (under consideration) 2004/11/30 RICH 04 Workshop 18

Summary n MCP-PMT w/ <10 mm channel has excellent single photon counting performance up to 1. 5 T magnetic field. Some samples exhibits very sharp HPD like ¨ Gain > 106 single photon peak (better in B field) ¨ TTS < 35 ps (s) ¨ Unresolved issues: cross talk + Life time n New development are underway at Belle ¨ 1 x 4 linear array MCP-PMT TOP counter. Basic performance has been confirmed. ¨ TAC-based ASIC for high resol. time decoding. n Ga. As. P photocathode ? ¨ TTS <35 ps has been confirmed. ¨ Worth for consideration. 2004/11/30 RICH 04 Workshop Stay tuned ! 19

Backup Slides 2004/11/30 RICH 04 Workshop 20

TTS vs B-field 2004/11/30 RICH 04 Workshop 21

Gain vs HV Gain BINP 10 Burle 25 HPK 6 HPK 10 HV(k. V) 6 6 HPK 6 3 10 (B = 1. 5 T, H. V= 3. 6 k. V) BINP 10 3 10 (B = 1. 5 T, H. V= 3. 2 V) HPK 10 2 105(B = 1. 5 T, H. V= 3. 4 k. V) Burle 25 4 105(B = 0. 8 T, H. V= 2. 5 V) 2004/11/30 RICH 04 Workshop 22

Multi-anode MCP-PMT w/ Ga. As. P ? n The timing performance has been checked with single channel MCP-PMT sample. n According to HPK, Can be made. ¨ Effecive area ratio (cathode area/package) may be smaller. ¨ n Need clarify Life. ¨ Dark counts ¨ Cost ? ¨ 2004/11/30 HPK Data RICH 04 Workshop 23