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MPPC SaturationMPPC Saturation13/9/201113/9/2011

Shinshu UniversityShinshu University

High energy physics labHigh energy physics lab

Akito KobayashiAkito Kobayashi

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TableTable Back groundBack ground

Feature of MPPCFeature of MPPC PurposePurpose

Method of measurementMethod of measurement Set UpSet Up ResultResult

SummarySummary TaskTask

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International Linear Collider International Linear Collider (ILC)(ILC)

ILC is a new Linear Collider thatILC is a new Linear Collider thatuse erectron and positron.use erectron and positron.・・ The exact measurement of Higgs.The exact measurement of Higgs.・・ Discovery new physics such as SUSDiscovery new physics such as SUS

Y.Y.　　

International Large Detector(ILD)

＜＜ Feature of ILD CalFeature of ILD Cal ＞＞・・ The detection layer is segmented to improve space The detection layer is segmented to improve space resolution.resolution.＜＜ Devices requastedDevices requasted ＞＞・・ Small and anable to make many channel.Small and anable to make many channel.・・ Higher Gain.Higher Gain.・・ tolerant of strong magnetic field.tolerant of strong magnetic field.

↓↓

MPPCMPPC （（ Multi-Pixel Photon CounterMulti-Pixel Photon Counter ））　　　　

sensor

Calorie meterCalorie meter

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Feature of MPPCFeature of MPPCAPD(Avalanche Photo Diode) can amplify electron when APD(Avalanche Photo Diode) can amplify electron when

bias voltage is over break down voltage(Vbias voltage is over break down voltage(V00) .) .

APD’s output don’t depend on number of entering photons.APD’s output don’t depend on number of entering photons.

APD Pixel

MPPC curcuit

↓MPPC’s output is total of all of APD pixel output.

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Response performance Response performance of MPPCof MPPC

1exp1

pix

inpixfired N

NNN

APD can detect only one photo electron.APD can detect only one photo electron.

→→MPPC can’t detect more photon than number of MPPC can’t detect more photon than number of pixel at once.pixel at once.

Number of detected photon and input photon is Number of detected photon and input photon is depend on the following function:(1).depend on the following function:(1).

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PurposePurpose

MPPC output is dependent on Number of Pixel.MPPC output is dependent on Number of Pixel. ↓ ↓

Compare response curve to some MPPC’s.Compare response curve to some MPPC’s.（（ number of pixel = 100 , 400 , 1600 , 2500 , 4400number of pixel = 100 , 400 , 1600 , 2500 , 4400 ）） Evaluate dynamic range of MPPC.Evaluate dynamic range of MPPC. Relation between time structure and response curve.Relation between time structure and response curve. Compare measurement and simulation.Compare measurement and simulation.

↓↓

Understand the performance of MPPCUnderstand the performance of MPPC

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Method of measurement of Method of measurement of Response CurveResponse Curve

Light hits MPPC and PMT.Light hits MPPC and PMT. Measure the signal of MPPC and PMT by ADC.Measure the signal of MPPC and PMT by ADC. MPPC’s ADC mean convert to NMPPC’s ADC mean convert to Nfired.fired.

Data plot Xaxis : PMT output , Yaxis : NData plot Xaxis : PMT output , Yaxis : Nfired.fired.

This plot is called “Response Curve”This plot is called “Response Curve”

MPPC

PMTLight source

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Convert ADCCount to NConvert ADCCount to Nfiredfired

dVe

C

Ae

rd

2dV

e

C

e

rd

3dodV ddVr

Cd

41

200

dd

ADCCountN dfired

If MPPC’s parameters (C and V0) are known.

Without AMP(A=1)

The d’ is computed by considering errors of V0.

Divide by MPPC ADCCount to d’ to determine Nfired.

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Object of measurementObject of measurement 5 type of MPPC (sensor : 1mm ×1 mm)5 type of MPPC (sensor : 1mm ×1 mm)

pixelpixel 数数 4400 2500 1600 400 100

C[fF]C[fF] 7.47.4 12.712.7 19.019.0 9898 352352 　　

VV00[V][V] 70.9570.95 71.5171.51 69.5269.52 70.0670.06 　　 　　 69.7569.75

4400 , 400 , 100 pixel package 2500 , 1600 pixel package

To measure response curve at same condition, we need to make special measurement system.

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Design of Set UpDesign of Set Up

27~28cm

24c

m

14cm

0.1cm

8cm

9.5cm

1.4cm

PMT Fiber

MPPC

LED

WLS Fiber

3cm

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PhotoPhoto

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Condition of Condition of measurementmeasurement

・ Gate Pulse Width = 150ns・ Light Pulse Width = 15ns (half width)・ PMT bias = 600V・ Gain = 1.5×105

LED driver output

pixel 4400 2500 1600 400 100

dV[V] 3.25 1.89 1.26 0.25 0.07

Vbias[V] 74.2 73.4 70.78 70.31 69.82

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Result of measurementResult of measurement

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2 MPPC plot2 MPPC plot

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SummarySummary

Measurement of MPPC’s response curveMeasurement of MPPC’s response curve

↓↓ Measurement of response curve of another pakage MPMeasurement of response curve of another pakage MP

PC is success.PC is success. Deference of NDeference of Nfiredfired in large X between 5 MPPC’s is see in large X between 5 MPPC’s is see

n.n. MPPC saturation phenomena can’t be seen for all MPPMPPC saturation phenomena can’t be seen for all MPP

C.C.

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TaskTask

More narrowly the time width of light pulse.More narrowly the time width of light pulse. Simulation of response curve.Simulation of response curve. Measurement using another light source.Measurement using another light source. Evaluate reproducibility of measurement Evaluate reproducibility of measurement

system system

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Back UpBack Up

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MPPC fixed partMPPC fixed part MPPC is putted in fixing boardMPPC is putted in fixing board Fixing board is pressed down by two screwsFixing board is pressed down by two screws

Fixing board Fixing board

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PMT fixed partPMT fixed part PMTPMT は左右＋後方から金具で固定は左右＋後方から金具で固定 ファイバーはプラスチック版（厚さファイバーはプラスチック版（厚さ 1mm1mm））で固定で固定

ファイバーと光電面の間にグリス等はなしファイバーと光電面の間にグリス等はなし

ファイバー

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Fiber&LED fixed partFiber&LED fixed part ファイバーを溝にはめ込むファイバーを溝にはめ込む 光を当てる部分以外はテープで覆う光を当てる部分以外はテープで覆う 露光部分は反射材を被せる露光部分は反射材を被せる

反射材

LEDLED

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Saturation curve Saturation curve following function(1)following function(1)

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Response curve Response curve sample(1600pixel)sample(1600pixel)

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Result of 4400pixelResult of 4400pixel

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Result of 2500pixelResult of 2500pixel

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Result of 1600pixelResult of 1600pixel