Very-fast TOF Workshop, U of Chicago, Nov.18.2005.; Takayoshi Ohshima TIMING PROPERTIES OF MCP-PMT...

Very-fast TOF Workshop, U of Chicago, Nov.18.2005.; Takayoshi Ohshima

TIMING PROPERTIES OF MCP-PMT DEVICES- <10 psec TOF Counter -T. Ohshima (Nagoya U.)

1. TOP counter and TOF counter 2. R&D of MCP-PMT’s3. 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。


Hybrid Avalanche Photo-Diode S. Matsui et al, NIM A463 (2001) 220-226

Fine-mesh multi-anode PMT M. Hirose et al, NIM A460 (2001) 326-335

Linear array multi-anode PMT Y. Enari et al, NIM A547 (2005) 490-503

Micro-Channel Plate PMT M. Akatsu et al, NIM A528 (2004) 763-775

1. HPK10 (3809U-50-25X), 2. HPK6 (3809U-50-11X)3. BINP (multialkali) (GaAs extended)4. Burle (85001-501)

Photon device for TOP counterM. Akatsu et al, NIM A440 (2000) 124-135; T. Ohshima ICFA Instr. Bull. 20 (2000) 2

< 10 ps TOF counterTOP 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 を発想。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.

Quantum Efficiency

Collection Efficiency

photocathode material

cathode – 1st MCP gap

vacuum

Structure of MCP-PMT

Cross-talk

Multi-anode structure

Ion-feedback layer

Position resolution ~ 1 mm

Single photon sensitive

high detection efficiency

Fast timing TTS < 50 ps

Operational under 1.5 T

Long life-time

Rate dependence

1. TOP counter and TOF counter1. TOP counter and TOF counter


2. R&D of MCP-PMT’s (Single photon pulses) 2. R&D of MCP-PMT’s (Single photon pulses) (Transite Time Spread) TTS●Multi-anode linear-array PMT (L16 & L24) 70-80; 120 ps●Hybrid Avalanche Photo-Diode 150 ps●Micro-Channel-Plate PMT 30-40 ps

MCP(HPK10 3809U-50-25X)

HAPD(HPK R7110U-07)

L24(HPK R6135-L24X)

L16(HPK R5900-L16)

PMT(HPK H7195)1 ns/div

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。


Fluctuations　 of 1. TTS2. Decay-time (Td TTS)3. Light-path (Tγ TTS)4. Nγ

Points for TOF counter

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．）

Photo-statistics 1/Nγ is varied only

at Td, Tγ << TS.

1. 30-40 ps (MCP-PMT), 70-80 ps (L16)2. Cherenkov light3. Normal incidence (a timing spread due to quartz thickness = 1-2 ps for 1 cm quartz.)

⇒ = (30x2–30) ps /1cm/(12Nγ) = 9 ps/ Nγ/ 1 cm)4. 50 detected photons/1 cm quartz For short path, no chromaticity effect. = 30-40 ps/ 50 = 5-6 ps

quartz: n=1.47; =45o (for GeV/c particles)

time

photon signals

一

二

三

四

五

六

七


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。

矩形波で測定測定回路の寄与＝ 8.8psec

Divider

HPK C5594: bandwidth=50 kHz-1.5 GHz gain=36dB (@0.1 GHz) NF = 5 dB

Dividerdivider

HUBER+SUHNER SMA cable 　MULTIFLEX MF 141 ： Impedance=50 ohm Operating frequency= 18 GHz Capacitance=95 pF/m Time delay= 4.7 ns/m Attenuation= a f(GHz)^1/2 + b f(GHz) (a=0.37320), (b=0.02790) 　　　　　　　　

2. R&D of MCP-PMT’s (Test circuit) 2. R&D of MCP-PMT’s (Test circuit)

using single photons from a light-pulser壱

弐

参


NIM A528 (2004) 763-775, by M. Akatsu et al, “MCP-PMT timing property for single photons”

MCP(Micro-Channel Plate)

チャンネル径

Footnote: 開発研究の MCP-PMT 性能比較。

multialkali multialkali

2. R&D of MCP-PMT’s (MCP-PMT’s)2. R&D of MCP-PMT’s (MCP-PMT’s)


Footnote: ADC & TDC spectra

(pedestal = 100count)

=46ps

• HPK10 R3809U-50-25X

• BINP N4963

（１光子照射 ,HV:3.2kV)

Gain=106

=34ps

(pedestal = 100count)

Gain=3x106

Single photon peak

Single photon peak

2. R&D of MCP-PMT’s (ADC spectra) 2. R&D of MCP-PMT’s (ADC spectra)


2. R&D of MCP-PMT’s (Gain vs TTS) 2. R&D of MCP-PMT’s (Gain vs TTS)


2. R&D of MCP-PMT’s (TTS vs B)2. R&D of MCP-PMT’s (TTS vs B)


TTS=46 ps, N = 200/ 4 cm quartz, = 46/ 200 = 3 ps ⇒ expected = 9 ps including circuit fluctuation of 9 ps.

observed = 10.6 ps

⇒ With different TTS [ L16(TTS=80 ps) & MCP(TTS=46 ps) ] and similar Nγ’s, observed = 11-12 ps is attained,where the circuit fluctuations (7-9 ps) dominate the ambiguity.

3. TOF counter (TOF by HPK10)3. TOF counter (TOF by HPK10)

Footnote: HPK10 TOF のビームテスト。期待値＝９　ｐｓ　ｖｓ。測定値＝１０．６　ｐｓ。

Cerenkov radiator

Since the light-pulser’s jitter yields an essential contribution on the measurement,


3. TOF counter 　 (TOF－ PMT w/o Radiator)3. TOF counter 　 (TOF－ PMT w/o Radiator)

NIM A547 (2005) 490, Y.Enari et al, 　 Cross-Talk of a Multi-Anode PMT and Attainment of a s sim 10 ps TOF counter

Footnote: HPK10 を単独でビーム照射。分解能＝１３．６ psec 。

By hitting an MCP-PMT directly by charged beam,

TOF resolution of = 13.6 ps was attained.

HPK10(TTS=46 ps)


3. TOF counter 　 (TOF-PMT w/o Radiator (continue))3. TOF counter 　 (TOF-PMT w/o Radiator (continue))

● 　 window thickness = 4 mm 　⇒　　　 Nγexpected = 25 photons vs. Nγdetected = 50 photons

Inspection: 0 = [ 13.62 – 92 ]1/2 = 10 ps = 46 ps/ 21 (photons)

21 photons vs. 25 / 50 photons⇒ 　 Timing of photons from the 1st 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 。 GaAs 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。

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.


In a case the most photons produced at the window, equipping thicker window, 10 mm, would improve TOF resolution better than 10 ps.

3. TOF counter 　 (TOF-PMT w/o Radiator (continue))3. TOF counter 　 (TOF-PMT w/o Radiator (continue))

25x10/4=60 photons,

46 ps/ 60 =6 ps;

= 62+72 = 9 ps

Circuit error

Footnote: MCP-PMT(HPK10) 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、 GaAsP photo-cathode を想定していない。また、 HPK10(TTS= ４６ psec ）でなく、 HPK6 （ 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。

MCP-PMT (TTS=46 ps)

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.


3. TOF counter 　 (10 ps TOF-Counter)3. TOF counter 　 (10 ps TOF-Counter)

MCP-PMT (TTS=30 ps)

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 HPK ６ (TTS= ３０　 psec ）でなく HPK １０（ TTS= ４６ psec ）とすると分解能＝８－９ psec が期待できる。ただし、 GaAsP photo-cathode を想定していない。

particle Quartz (10mm) Nγ=60(60+50) photons

=30ps/ 60(110) =3-4 ps with 7 ps 　 circuit error

= 8 ps

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.


3.4 TOF counter 　 (2nd BEAM-TEST: 5 ps TOF Beam-Test) 3.4 TOF counter 　 (2nd BEAM-TEST: 5 ps TOF Beam-Test) Aims(1) Study of TOF resolution using SPC (Becker & Hickl GmbH’s) Time-Correlated Single Photon Counting Modules (SPC-134): - channel resolution = 813 fs - electrical time resolution = 4 ps RMS - repetition rates upto 200 MHz

(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 。

This SPC includes CFD, TAC, ADC, and MCA (Micro Channel Analyzer).

Up to here, the attained resolution was limited mostly by the uncertainty of readout circuit..


SET-UP

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:

Using HPK6 (TTS=30 ps) with 3 mm-thick window instead HPK10.


For SINGLE PHOTONS ADC, TDC and t (~30 ps)

raw signals

GAIN, TTS and CE vs HV

t for single photons(spc used)

2nd BEAM-TEST: “5 ps TOF Beam-Test” (cont.)

(CAMAC)

Pulser 　 (single photon) による測定


2nd BEAM-TEST: “5 ps TOF Beam-Test” (cont.)

For 3 GeV/c PIONS

Circuit resolution ( t = 4.1 ps ) TOF w/o radiator ( t = 7.7 ps ) TOF w radiator ( t = 6.2 ps )

Beam による測定。　 SPC の分解能。　 No radiator & 10 mm crystal 。 6.2(ps)2 – 4.1 (ps) 2 = 4.7 (ps) 2


t vs RADIATOR THICKNESS ■ 　 N vs RADIATOR THICKNESS

ADC distribution of MCP-plate alone

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.

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.


3.3 TOF counter 　(Know-How: Window materials)3.3 TOF counter 　(Know-How: Window materials)

チェレンコフ光子数2

1

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。

Borosilicate 1mm

Quartz 3-4 mmQuartz/ Borosilicate

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(3-4mm quatrz) and BINP(1mm Borosi).


3.3 TOF counter 　 (Know-How ：　 Photocathode materials) 3.3 TOF counter 　 (Know-How ：　 Photocathode materials)

Footnote: Bi-alkali はほうけい酸ガラスで、 multi-alkali は quartz か？　

Not only QE but also -range depend on material.

Cherenkov

∝ 1/

The choice of photo-cathode material is quite essential. GaAsP indicates much higher QE and wider sensitive frequency range. BINP serves Blue extended GaAs window, which also has a good property. Suitable choice of the material would improved TOF resolution by enlarging the number of photo-electrons.

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?


LIFT-TIMELIFT-TIME

No time to talk


4. Summary4. Summary

By R&DWe have developed MCP-PMT’s which satisfies the most of our requirements.TTS = 30 ps & t = 5 ps is obtained by a beam test.

R&D of MCP-PMT is now focused onGaAsP photocathode &Lifetime improvement

R&D of readout circuits is focused onHighly stable CFD &TDC

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Very-fast TOF Workshop, U of Chicago, Nov.18.2005.; Takayoshi Ohshima TIMING PROPERTIES OF MCP-PMT...

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