Time of Flight measurements with MCP-PMT · 2006/4/3-6 SNIC at SLAC 6 Beam test 1 z3GeV/c π−beam...

International Symposium on the Development of Detectors, 2006/4 at SLAC

Time of Flight measurementswith MCP-PMT

- Very high resolution TOF counter- Lifetime of MCP-PMTs

T.Ohshima, K.Inami, N.Kishimoto, M.Nagamine(Nagoya university, Japan)

2006/4/3-6 SNIC at SLAC 2

Introduction

~400mm

Linear-array type photon detector

LX

20mm

Quartz radiatorx

y

z

Photon device for TOP counterCherenkov ring imaging counter with precise time measurement (NIM A 440 (2000) 124)

For super B-factory

Single photon sensitivityGood transit time resolution (<50ps)Operational under 1.5T B-fieldPosition sensitive (~5mm)High detection efficiency

MCP-PMT is a good solution.In the course of R&D,

Idea of a few psec resolution TOF

MCP-PMT for TOP counter


0

200

400

600

0 0.1 0.2 0.3 0.4

Arb

itrar

y sc

ale

0

10

20

30

40

Arb

itrar

y sc

ale

0 2 4 6Emission and propagation time (ns)

StructureSmall-size quartz (cm~mm length)

Cherenkov light (Decay time ~ 0) extremely reduce time dispersion compared to scintillation (τ ~ ns)

MCP-PMT (multi-alkali photo-cathode)TTS < 50ps even for single photongives enough time resolution for smaller number of detectable photons

Cherenkov light

Scintillation (BC408)Test counter

Simulation

Nγ~240

Nγ~820

High resolution TOF


MCP-PMTMicro-Channel-Plate

Tiny electron multipliersDiameter ~10µm, length ~400µm

High gain~106 for two-stage type

→ Fast time responsePulse raise time ~500ps, TTS < 50ps

can operate under high magnetic field (~1T)

Photo-cathode MCP plates Anode

Photon

Single photonChannel

~400µm

φ~10µmInput electron

HV

MCP channel


MCP-PMT (2)

Window size : 25mmφ

R3809U-50-25X

ADC (count/0.25pC)

0

200

400

600

100 120 140N

um

be

r o

f E

ve

nts

TDC (count/25psec)

0

500

1000

1500

-20

Nu

mb

er

of

Ev

en

ts

200

σ=46psfor single photon

single photon peak

0

200

400

600

800

1000

1200

100 110 120 130ADC (1bin/0.25pC)

even

t

0

200

400

600

800

1000

-20 -10 0 10 20

30.4psec

TDC(25ps/count)

even

t

Hamamatsu R3809U-50 (multi-alkali photo-cathode)

R3809U-50-11X

Window : 11mmφ

MCP hole 10µmφ

MCP hole 6µmφ

Gain ~ 106


Beam test 13GeV/c π− beam

at KEK-PS π2 linePMT: R3809U-50-25XQuartz radiator

16x16x40mm with Al evaporation

TOF between two countersevaluate the time resolution

TOF counter with and without quartz radiator

To confirm MCP-PMT’s behavior for passage of charged particles

Test counter

Beam

Trigger counter

Trigger counter

Tile TOF counter

Quartz

MCP PMT

z

x

5 x5 x10 mm Scinti. BC408x y z

16 x16 x40 mmx y z

HPK R3809U-50-25XPhoto-Cathode φ25mmsingle-photon TTS 50psec

40mm

60cm


Beam test 1 resultWith quartz radiator

Number of photons ~ 250agree with expectation of simulation ~240

Time resolution ~ 10.6ps

Without radiatorNumber of photons ~ 50

Cherenkov light from PMT windowTime resolution ~ 13.6ps

Resolution is limited by readout electronics. (σelec~8.8ps)

Expected intrinsic resolution ~5.9pstof (ps)

0 25 50-25-50

0 25 50-25-50tof (ps)

with radiator

without radiator


Beam test 2Confirmation of intrinsic time resolution

ImprovementsReadout electronics

σelec.: 8.8ps 4psTime-correlated Single Photon Counting Modules (SPC-134, Becker & Hickl GMbH’s)

CFD, TAC and ADC Channel width = 813fsElectrical time resolution = 4ps RMS

MCP-PMTTTS: ~46ps ~30ps10µm hole 6µm hole

R3809U-50-25X -11X


Beam test 2 setup3GeV/c π− beam

at KEK-PS π2 linePMT: R3809U-50-11XQuartz radiator

10φx40zmm with Al evaporation

0

100

200

300

40 80 120

4.1ps

Even

tsTDC (ch/0.814ps)

Elec. resolutionBeamTrig.1

Trig.2TOF1 TOF2

30cm

Trig.1 Coinc. Discri.Divider

Trig.2

TOF2

TOF1PowerSpliter

Discri.

Discri.Divider

Start Stop

π, 3GeV/c-

SPC-134

2006/4/3-6 SNIC at SLAC 10

Beam test 2 setup photo

TOF1

TOF2Trigger

Trigger

2006/4/3-6 SNIC at SLAC 11

Beam test 2 resultWith 10mm quartz radiator

+3mm quartz windowNumber of photons ~ 180Time resolution = 6.2psIntrinsic resolution ~ 4.7ps

Without quartz radiator3mm quartz windowNumber of photons ~ 80

Expectation ~ 20 photo-electrons

Time resolution = 7.7ps

Even

ts

100

200

300

400

40 80 120 1400TDC (ch/0.814ps)

6.2ps

100

200

300

40 80 120 1400

TDC

7.7ps

(ch/0.814ps)Ev

ents

2006/4/3-6 SNIC at SLAC 12

Beam test 2 result (cont’d)Nγ, σTOF v.s. radiator thickness

Extra photo-electronsNp.e. from short distance is larger than that of expected.

Time-resolution behaviorResolution is gradually worse.

Extra p.e. would affect the resolution dependence.

2

4

6

8

10

12

14

Beam-test Simulation

100

200

300

Quartz thickness (mm)0 20 4010 30 500 20 4010 30 50

Quartz thickness (mm)σ

(ps)

TOF

Np.

e.

Counter-1

SimulationCounter-2

2006/4/3-6 SNIC at SLAC 13

LifetimeHow long can we use MCP-PMT under high hit rate?

Light load by LED pulse (1~5kHz)20~100 p.e. /pulse (monitored by normal PMT)

HPK (x2) Russian (x5)Al protection O X O X

65% 55-60%Correction eff. 37% 40-60%Effective area 11mmφ 18mmφ

Gain 1.9x106 1.5x106 3-4x106

29ps 30-40ps

Bias angle 13deg 5deg

TTS 34psPhoto-cathode Multi-alkali (NaKSbCs)Quantum eff. at 400nm 21% 19% 16-20%

2006/4/3-6 SNIC at SLAC 14

Gain & TTS for single photonGain TTS

Russian w/o Al (#6)

HPK w/o Al

Russian w/ Al(#32)

HPK w/ Al

－before－after

σ=31psσ=36ps

σ=43psσ=32ps

σ=34psσ=34ps

σ=29psσ=33ps

0

0.2

0.4

0.6

0.8

1

1.2

0 200 400 600 800 1000 1200Output charge (mC/cm2)

Rel

ativ

e ga

in

HPK w/ AlHPK w/o Al

Russian w/ Al (#32)Russian w/ Al (#35)Russian w/ Al (#38)Russian w/o Al (#6)Russian w/o Al (#11)

TTS is stable within the gain drops.

~1012 p.e./cm2

with 106 gain

2006/4/3-6 SNIC at SLAC 15

Quantum efficiencyQ.E. Before/After

λ=400nm

0

0.2

0.4

0.6

0.8

1

1.2

0 200 400 600 800 1000 1200

Rel

ativ

e Q

.E.

Output charge (mC/cm2)

10-3

10-2

10-1

1

200 300 400 500 600 700 800 900λ(nm)

Q.E

. rat

io

HPK w/ AlHPK w/o Al


• Small Q.E. drop for HPK with protection• Fast degradation for longer wavelength

~1012 p.e./cm2

with 106 gain

2006/4/3-6 SNIC at SLAC 16

SummaryHigh resolution TOF counter

Small quartz as Cherenkov radiator MCP-PMT (TTS ~30ps for single photon)Readout system (time resolution ~4ps)Time resolution of 6.2ps have been measured.

4.7ps intrinsic resolution

Lifetime test of MCP-PMTsAl protection layer works well to stop feedback ions.MCP-PMT by HPK with Al layer is best solution.

For more detail, please refer NIM A 528, 763 (2004) and new paper to be published in NIM A.

2006/4/3-6 SNIC at SLAC 17

Separation power

1

10

0 2 4 6Momentum (GeV)

Sep

arat

ion

3

σ=100psecσ=50psecσ=20psecσ=10psecσ=5psec

L=1.0m

2006/4/3-6 SNIC at SLAC 18

Fluctuation of Readout elec.8 TDC channels with logic pulse

0

2

4

6

8

10

12

14

16

8Number of used channel

RM

S(p

sec)

2 4 60

■ 8.8psecpsec8.8=moduleσ ch#

8.8

Diveder

CAMAC

ADC

TDC

Discri.

Gate

Clock Generator Discri.

8

1

2

startstop

startstop

startstop

ttT

ttT

ttT

−=

−=

−=

8

2

1

8

2

1

2)()(

2)43()21( 4321 stopstopstopstop ttttTTTT +−+

=+−+

22/)21(

22

2121

TTstop

stopstopTT

−

−

≅

+=

σσ

σσσ

42/)4321( TTTT

stop−−+≅

σσ

2121 stopstop ttTT −=−

2006/4/3-6 SNIC at SLAC 19

Lifetime test (setup)

2006/4/3-6 SNIC at SLAC 20

Quantum efficiency

10-2

10-1

1

10

200 300 400 500 600 700 800 900λ(nm)

Q.E

.(%)

HPK w/ AlHPK w/o Al


Time of Flight measurements with MCP-PMT · 2006/4/3-6 SNIC at SLAC 6 Beam test 1 z3GeV/c π−beam...

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Transcript of Time of Flight measurements with MCP-PMT · 2006/4/3-6 SNIC at SLAC 6 Beam test 1 z3GeV/c π−beam...