TIMING PROPERTIES OF MCPPMT DEVICES s10 psec TOF

TIMING PROPERTIES OF MCP-PMT DEVICES - s<10 psec TOF Counter T. Ohshima (Nagoya U. ) 1. TOP counter and TOF counter 2. R&D of MCP-PMT’s 3. TOF counter ■ New Approaches ■ Beam test (1) ■ Beam test (2) ■ Know-how Footnote: MCP-PMTにもとずく 10 psec TOF counter R&Dの報告である。 Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

1. TOP counter and TOF counter Photon device for TOP counter u. Linear array multi-anode PMT Y. Enari et al, NIM A 547 (2005) 490 -50 u. Fine-mesh multi-anode PMT M. Akatsu et al, NIM A 440 (2000) 124 -135; T. Ohshima ICFA Instr. Bull. 20 (2000) M. 2 Hirose et al, NIM A 460 (2001) 326 - Single photon sensitive Quantum Efficiency Collection Efficiency high detection efficiency photocathode material u. Hybrid Avalanche Photo-Diode S. Matsui et al, NIM A 463 (2001) 220 -2 u. Micro-Channel Plate PMT M. Akatsu et al, NIM A 528 (2004) 763 -7 Fast timing TTS < 50 ps cathode – 1 st MCP gap Structure of MCP-PMT Position resolution ~ 1 mm Multi-anode structure Cross-talk Operational under 1. 5 T Long life-time Rate dependence Ion-feedback layer vacuum 1. HPK 10 (3809 U-50 -25 X), 2. HPK 6 (3809 U-50 -11 X) 3. BINP (multialkali) 4. (Ga. As extended) 5. 4. Burle (85001 -501) < 10 ps TOF counter TOP counterのphoton detectorの開発が動機。要請する性能を満たすもの⇒PMT, HAPD & MCPへ。この過程でMCP-PMTの光時間分解能を活用しTOF counetrを 回路を除くと 5 psの分解能をすでに得る。 By doing R&D on these issues, most of them are now in satisfaction. In the course of R&D studies, we come across an idea to have less 10 ps TOF counter. Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

2. R&D of MCP-PMT’s (Single photon pulses) (Transite Time Spread) TTS ●Multi-anode linear-array PMT (L 16 & L 24) ●Hybrid Avalanche Photo-Diode ●Micro-Channel-Plate PMT 70 -80; 120 ps 150 ps 30 -40 ps HAPD(HPK R 7110 U-07) L 16(HPK R 5900 -L 16) PMT(HPK H 7195) 1 ns/div L 24(HPK R 6135 -L 24 X) MCP(HPK 10 3809 U-50 -25 X) Footnote: これまで開発研究した光検出器の１光子に対する信号と測定TTS。信号の立ち上がりの速さを比較せよ。 Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

Points for TOF counter 一 Fluctuations of 1. TTS 2. Decay-time (Td TTS) 3. Light-path (Tγ TTS) 4. Nγ Photo-statistics 1/ Nγ is varied only at Td, Tγ << TS. 六 二 五 四 三 七 1. 2. 3. 4. 5. 6. 7. time photon signals quartz: n=1. 47; q=45 o (for Ge. V/c particles) 30 -40 ps (MCP-PMT), 70 -80 ps (L 16) Cherenkov light Normal incidence (a timing spread due to quartz thickness = 1 -2 ps for 1 cm quartz. ) ⇒ s = (30 x 2– 30) ps /1 cm/( 12 Nγ) = 9 ps/ Nγ/ 1 cm) 4. 50 detected photons/1 cm quartz For short path, no chromaticity effect. s = 30 -40 ps/ 50 = 5 -6 ps Footnote: TOF精度を決める要因。⇒MCP-PMY/Cherenkov/path/# photons （時間広がりがなく、多量の光子が＝１．＆４．） Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

2. R&D of MCP-PMT’s (Test circuit) 矩形波で測定 測定回路の寄与＝ 8. 8 psec 弐 壱 usingle photons from a light-pulser Divide r 参 HPK C 5594: bandwidth=50 k. Hz-1. 5 GHz gain=36 d. B (@0. 1 GHz) NF = 5 d. B divider Divide r HUBER+SUHNER SMA cable MULTIFLEX MF 141： Impedance=50 ohm Operating frequency= 18 GHz Capacitance=95 p. F/m Time delay= 4. 7 ns/m Attenuation= a f(GHz)^1/2 + b f(GHz) (a=0. 37320), (b=0. 02790) Footnote: TOF精度を決める要因。⇒回路系の精度（実測値＝ 7 -9 psec）。ビームテストではatt. &ampは不要。 Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

2. R&D of MCP-PMT’s (MCP-PMT’s) NIM A 528 (2004) 763 -775, by M. Akatsu et al, “MCP-PMT timing property for single photons” multialkali MCP(Micro-Channel Plate) チャンネル径 Footnote: 開発研究のMCP-PMT性能比較。 Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

2. R&D of MCP-PMT’s (ADC spectra) • HPK 10 R 3809 U-50 -25 X Gain=106 s=46 ps Single photon peak (pedestal = 100 count) • BINP N 4963 Gain=3 x 106 s=34 ps （１光子照射, HV: 3. 2 k. V) Single photon peak (pedestal = 100 count) Footnote: ADC & TDC spectra Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

2. R&D of MCP-PMT’s (Gain vs TTS) Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

2. R&D of MCP-PMT’s (TTS vs B) Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

Cerenkov radiator 3. TOF counter (TOF by HPK 10) Since the light-pulser’s jitter yields an essential contribution on the measu TTS=46 ps, N = 200/ 4 cm quartz, s 0 = 46/ 200 = 3 ps ⇒ sexpected = 9 ps including circuit fluctuation of 9 ps. sobserved = 10. 6 ps ⇒ With different TTS [ L 16(TTS=80 ps) & MCP(TTS=46 ps) ] and similar Nγ’s, sobserved = 11 -12 ps is attained, where the circuit fluctuations (7 -9 ps) dominate the ambiguity. Footnote: HPK 10 TOFのビームテスト。期待値＝９ ｐｓ ｖｓ。測定値＝１０．６ ｐｓ。 Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

3. TOF counter (TOF－PMT w/o Radiator) NIM A 547 (2005) 490, Y. Enari et al, Cross-Talk of a Multi-Anode PMT and Attainment of a s sim 10 ps TOF counter HPK 10(TTS=46 ps) By hitting an MCP-PMT directly by charged beam, TOF resolution of s = 13. 6 ps was attained. Footnote: HPK 10を単独でビーム照射。分解能＝１３．６ psec。 Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

3. TOF counter (TOF-PMT w/o Radiator (continue)) ● window thickness = 4 mm ⇒ Nγexpected = 25 photons vs. Nγdetected = 50 photons MCP had a 4 mm-thick quartz window, so that about 20 -25 detectable photo-electrons were expected while we observed about twice. At the time, it was inferred that the extra photons more than the expectation might be yielded by MCP layer itself. However, the measured and readout system resolutions of 13. 6 ps and 9 ps indicate the intrinsic resolution of the MPC be 10 ps, which corresponds about detectable 20 photo-electrons. Where these extra photo-electrons come from is a mystery. Anyway, MCP itself provides 10 ps resolution. Inspection: s 0 = [ 13. 62 – 92 ]1/2 = 10 ps = 46 ps/ 21 (photons) 21 photons vs. 25 / 50 photons ⇒ Timing of photons from the 1 st MCP plate is 100 ps earlier than those from photo-cathode, but its gain would be lower so that effective # of photons would be less than 25. ⇒ Yield of 25 photons is really from the MCP? Footnote: 実測値＝１３．６ psec。Ga. As photo-cathodeにすればphoton数は２倍、分解能＝１０ psecが期待できる。MCP-PMT自体が高分解能TOF counter として働く。 Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

3. TOF counter (TOF-PMT w/o Radiator (continue)) In a case the most photons produced at the window, equipping thicker window, 10 mm, would improve TOF resolution better than 10 ps. 25 x 10/4=60 photons, 46 ps/ 60 =6 ps; s = 62+72 = 9 ps Circuit error When MCP has a thick quartz window, say, 10 mm, then 60 photo-electrons and 6 ps resolution are expected. Including readout system uncertainty, suppose to be it 7 ps, results in 9 ps accuracy in total. If MCP having better TTS and better circuit are prepared, the resolution will be improved. MCP-PMT (TTS=46 ps) Footnote: MCP-PMT(HPK 10)のwindowを 10 mmのquartzとする。また、回路系の分解能＝９→７ psecとする。 そうすると、MCP-PMT単独で分解能＝９ psecが期待できる。ただし、Ga. As. P photo-cathodeを想定していない。 また、HPK 10(TTS=４６ psec）でなく、HPK 6（TTS=30 psec）ならばwindowは５．６ mmでよい。 総体として、回路系の分解能を改良することが最重要。 Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

3. TOF counter (10 ps TOF-Counter) s=30 ps/ 60(110) =3 -4 ps with 7 ps circuit error MCP-PMT (TTS=30 ps) s= 8 ps particle Or, put 10 mm-thick quartz in front of MCP, for instance, with 30 ps TTS. 3 -4 ps intrinsic resolution is attained. Readout system uncertainty would dominate the resolution of 8 ps. Quartz (10 mm) Nγ=60(60+50) photons Footnote: 10 mmのquartz輻射体を設ける。 Photon数は６０（quartzから）と５０（PMTから）であり、回路系の分解能＝９→７ psecとする。 その結果、分解能＝８ psecが期待できる。MCP-PMTをHPK６(TTS=３０ psec）でなくHPK１０（TTS=４６ psec）とすると分解能＝８－９ psecが期待できる。 ただし、Ga. As. P photo-cathodeを想定していない。 Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

3. 4 TOF counter (2 nd BEAM-TEST: 5 ps TOF Beam-Test) Up to here, the attained resolution was limited mostly by the uncertainty of readout circuit. . n Aims (1) Study of TOF resolution using SPC (Becker & Hickl Gmb. H’s) Time-Correlated Single Photon Counting Modules (SPC 134): - channel resolution = 813 fs - electrical time resolution = 4 ps RMS - repetition rates upto 200 MHz This SPC includes CFD, TAC, ADC, and MCA (Micro Channel Analyzer). (2) Study of extra photons (from MCP itself? ) 回路系の分解能 7 -8 ps。これが分解能を決めている。SPC（分解能４ｐｓ）を当面使用して、MCP-PMTの分解能をstudy。 Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

Using HPK 6 (TTS=30 ps) with 3 mm-thick window instead HPK 10. n SET-UP n LOGIC CIRCUIT The thickness of quartz radiator is varied. We don’t need any other readout electronics for MCP’s; only the common stop signal is prepared by scintillation counters. - cable: SMA, BNC - discri: 300 MHz - SPC-134: 0. 86/count (CFD-TAC-ADC) - AMP: 50 k-1. 5 GHz - ATTN: < 18 GHz - power splitter: Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

2 nd BEAM-TEST: “ 5 ps TOF Beam-Test” (cont. ) n. For SINGLE PHOTONS raw signals ADC, TDC and st (~30 ps) (CAMAC) n. GAIN, TTS and CE vs HV photons(spc used) Pulser (single photon) による測定 Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima st for single

2 nd BEAM-TEST: “ 5 ps TOF Beam-Test” (cont. ) n. For 3 Ge. V/c PIONS Circuit resolution ( s t = 4. 1 ps ) radiator ( s t = 6. 2 ps ) TOF w/o radiator ( s t = 7. 7 ps ) Beam による測定。 SPCの分解能。 No radiator & 10 mm crystal。 TOF w 6. 2(ps)2 – 4. 1 (ps) 2 = 4. 7 (ps) Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

Although the number of the photo-electrons increases by using thicker quartz, the resolution gradually deteriorates. It is because the uncertainty of the light path due to the quartz thickness. n s t vs RADIATOR THICKNESS ■ Ng vs RADIATOR n. ADC distribution of MCP-plate alone Almost 1 photo-electrons is seen on an average. The extra photo-electrons are not produced at MCP, it might be at the MCP window. Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

3. 3 TOF counter チェレンコフ光子数 (Know-How: Window materials) In order to have larger number of photo-electrons, a consideration of the window material is important. Photon yields iare a few times different between HPK(3 -4 mm quatrz) and BINP(1 mm Borosi). Quartz/ Borosilicate Quartz 3 -4 mm Borosilicate 1 mm Footnote: quartz, borosilicate windowで検出できる光の波長特性が変わる。輻射体が短い場合はchromaticityも効かないので、quartzがよい。 Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

3. 3 TOF counter (Know-How： Photocathode materials) In order to further improve the resolution, we need more photo-electrons. Using thicker radiator rather deteriorates the resolution. Our detector equips already 10 mm-thick quartz. How to increase the number of photo-electrons? Cherenko v ∝ 1/ l 2 Not only QE but also l-range depend on material. Footnote: Bi-alkaliはほうけい酸ガラスで、multi-alkaliはquartzか？ The choice of photo-cathode material is quite essential. Ga. As. P indicates much higher QE and wider sensitive frequency range. BINP serves Blue extended Ga. As window, which also has a good property. Suitable choice of the material would improved TOF resolution by enlarging the number of photo-electrons. Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

LIFT-TIME No time to talk Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima

4. Summary By R&D n. We have developed MCP-PMT’s which satisfies the most our requirements. ns. TTS = 30 ps & st = 5 ps is obtained by a beam test. R&D of MCP-PMT is now focused on n. Ga. As. P photocathode & n. Lifetime improvement R&D of readout circuits is focused on n. Highly stable CFD & n. TDC Very-fast TOF Workshop, U of Chicago, Nov. 18. 2005. ; Takayoshi Ohshima