10 psec
psec Time-Of-FlightTime-Of-Flight
10Counter
Counter
T.Ohshima
Ohshima(Nagoya(NagoyaU.)
U.)
T.

●Points for TOF counter
Photo-detector●Measurements - Beam tests●New Approaches●Know-howFootnote: MCP-PMTにもとずく 10 psec TOF counter R&Dの報告である。

1.Points forfor TOF
TOF counter/counter/
1.Points
Photo-detectors (Transite Time Spread) TTS
Photo-detectors●Multi-anode linear-array PMT (L16 & L24)
●Hybrid Avalanche Photo-Diode●Micro-Channel-Plate PMT

70-80; 120 ps
150 ps30-40 ps

HAPD(HPK R7110U-07)

L16(HPK R5900-L16)

PMT(HPK H7195)
1 ns/div
L24(HPK R6135-L24X)

MCP(HPK 3809U-50-25X)

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。

1.Points forfor TOF
TOF countercounter
1.Points
Fluctuations of
1. TTS
2. Decay-time (Td ≤ TTS)
3. Light-path (Tγ ≤ TTS)
4. Nγ Photo-statistics 1/√Nγ is varied onlytime

photon signals

at Td, Tγ << TTS.
quartz: n=1.47;
θ=45o (for GeV/c particles)

1. 30-40 ps (MCP-PMT), 70-80 ps (L16)
2. Cherenkov light
3. Normal incidence⇒ σ = (30x2–30) ps /1cm/(√12Nγ) = 9 ps/ √Nγ/ 1 cm)
4. 50 detected photons/1 cm quartz

For short path, no chromaticity effect.
σ = 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．）

1.Points forfor TOF
TOF countercounter (continue)(continue)
1.Points
ND filter

HPK PLP
λ=408nm
Pulse-Width<50psec
jitter 10psec

矩形波で測定MCP-PMT

測定回路の寄与＝ 8.8psec

Laser
Attenuatorslit

HPK C5594 36dB

AMP 50k 1.5GHz

Black BoxDiscri. 2

Clock Generator

DivederDivider
ADCDiveder
Divider

Discri.

TDC
Gate

CAMAC

ADC
Discri. 1

TDC
Gate

CAMAC
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。

82.Measurements
2.Measurements

L16-TOFNIM submitted by Y.Enari et al, Cross-Talk of a Multi-Anode PMT and Attainment of a σ sim 10 ps TOF counter

TTS=80 ps, Nγ = 120-160/ 4 cm quartz,

16 independent measures

σ0= 80/√ 9 (photons/channel) / √16 = 7 ps
⇒ σexpected = 11 ps
including circuit fluctuation of 9 ps.

particle

Two detectors

Footnote: L16-PMTによるTOF。１６の独立な測定⇒期待値＝11 psec。

Total Resolution
Single channel Resolution

σ = 30 ps

Footnote: ビームテストのデータ、各チャンネル分解能＝30 psec⇒１６チャネルでは12.1 psec。

σobserved= 12.1 ps

Footnote: Systematic errorの評価。 j＝１６と ｊ＝４での寄与が大きい。

2.Measurements
2.Measurements

MCP-TOFNIM 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。

2.Measurements // MCP
MCP spectra
spectra2.Measurements
MeanRMS

600

Number of Events

Number of Events• HPK R3809U-50-25X
113.8
7.027

Gain=106

RMS1500

3.196

σ=46ps1000

400

20005000100120

140-20020

TDC (count/25psec)

ADC (count/0.25pC)(pedestal = 100count)

1000

IDEntries
MeanRMS

Number of events• BINP N4963

1765
16671
161.9
26.32

RMS

4000

Gain=3x106

800

2.377

σ=34ps

3000

600（１光子照射,HV:3.2kV)

2000
400

1000

200

500 100

0150

200

250

2(pedestal = 100count)

300

-200

TDC (count/25psec)

20

Footnote: ADC & TDC spectra

2.Measurements //2.Measurements

TOF byby HPK10
HPK10TOF

TTS=46 ps, Nγ = 200/ 4 cm quartz,
σ0 = 46/√ 200 = 3 ps
⇒ σexpected = 9 ps
including circuit fluctuation of 9 ps.

σobserved = 10.6 ps⇒ With different TTS [ L16(TTS=80 ps) & MCP(TTS=46 ps) ] andsimilar Nγ’s, σobserved = 11-12 ps is attained,where the circuit
fluctuations (7-9 ps) dominate the ambiguity.
Footnote: HPK10 TOFのビームテスト。期待値＝９ ｐｓ ｖｓ。測定値＝１０．６ ｐｓ。

Summary
1. TOF resolution = 10 ps achieved !
2. K/pi separation at Belle (Belle is a relatively smallspectrometer)⇒ ~ ４ σ at 4 GeV/c

3. Issues to be solved:(1) MCP-PMT lifetime(2) enlargement of radiator(3) precise circuit