Beta-ray test for strip scintillator readout MPPC GLD Cal group KEK 06/2/28 (Tue) Niigata university Sayaka IBA

Contents 1. Motivation 2. Best type of scintillator surface covering 3. Readout MPPC 4. Setup of beta-ray test 5. Results 1. Signal 2. Discussion of number of photon from fiber 6. Compare with readout PMT 7. Summary 8. Future plan

1. Motivation Scintillator Study  Compare of many type of surface covering  Select 10x40x2mm and 3M film MPPC study  Measurement of performances Beta-ray bench test  (scinti + WLS fiber + MPPC) Example of future Calorimeter design Scintilltor : 10x40x2mm Readout : MPPC Can MPPC really receive few photon from scintillator?? Compare to number of photon from strip scintillator readout MAPMT studied by Jacosalem-san Can MPPC really receive few photon from scintillator?? Compare to number of photon from strip scintillator readout MAPMT studied by Jacosalem-san

2. Best type of scintillator surface covering From Jacosalem-san study 3M radiant mirror film has the greatest pulse height Using 40mm length, we can catch enough signal 3M Radiant Mirror Film Teflon Black tape 3M radiant mirror film Teflon Al evaporation White paint + teflon White paint Black tape Au evaporation 40mm80mm120mm Select 3M film surface covering and 40mm length for beta-ray test Select !

3. Readout MPPC First type from HPK,100pixels Gain : 1.41x10 7 Deviation of PH (RMS) : 10% Efficiency (average of 50pixels) : ~59% at 49.0V Efficiency (laser light all covered; include cross talk) : ~75% at 49.0V. ~80% at 49.1V MPPC overview MPPC 100pixels (10x10pixels) First type ~85um ~100um Efficiency : ≧ 1pixel, Bias : 49.0V

4. Setup of beta-ray test We connected scintillator and MPPC through wavelength sifter fiber and tried beta ray test Measurement conditions  Scintillator : 10x40x2mm strip type (surface : 3M mirror sheet)  MPPC : first MPPC (100pixels), Bias 49.1V  Source : 90Sr (beta-ray)  WLS fiber : Φ1.0mm, length 20cm, Y-11 (Kuraray)  Trigger : scintillator + PMT Setup

5. Results MPPC readout timing is same level as PMT timing No right leak Signal from oscilloscope (up) from MPPC, (down) from PMT Pedestal (using clock) Signal ADC graph 250ns 2mV (MPPC) MPPC Trigger PMT

Results cont… number of photoelectron Pulse height = arithmetical mean （算術平均） - pedestal mean = 66.1 (ADCcount) Number of detection photoelectron from MPPC = 6.1pe pedestal 1pixel event 2pixel Number of photoelectron = Pulse height (ADCcount) 10.8 (ADCcount/1pe) # of Event ADCcount MPPC can detect MIP signal

Results cont… number of photon from fiber Light spread loss from fiber PDE PMT readout MPPC readout QE Checked number of photon from fiber Both readout (MPPC and PMT) type use same condition scintillator and fiber So, number of photon from fiber must be same Efficiency is different between MPPC and PMT We can’t discuss the merits to compare only number of photoelectron or pixel We considered,,, Efficiency for MPPC readout Particle detection effect (PDE; ε) Light spread loss from fiber Efficiency for PMT readout Only quantum efficiency (QE)

Results cont… We considered to PDE and light spread loss from fiber The optical resin is coated on detection surface of MPPC  Light spread from fiber and MPPC has light loss  43% loss for 1.0mm diameter fiber PDE (ε) = ε geom ×QE×ε guiger = 50%×80% (at 49.1V) = ~40% Light spread loss from fiber N photons = 15.8 (photons) Consider to light loss -> Number of photon from fiber = ~28(photons) Number of photon for MPPC detection : N photons ( # of fired pixel : N fired = 6.1, #of total pixel N tot = 100 )

We measured beta-ray signal from scintillator PMT readout to compare MPPC readout  Measured by Jacosalem-san Measurement conditions  Readout PMT : 16ch MAPMT (H , HV: -950V, QE: ~20%)  Same as conditions of readout MPPC Scintillator : 10x40x2mm, surface covering 3M film Beta-ray source : 90Sr WLS fiber : diameter 1.0mm, length 20cm from PMT 6. Compare of scinti - PMT result

PMT result cont… -- number of pe and photon  Number of photoelectron from PMT = 5.8 pe Number of pe = number of photon from fiber x QE of PMT (20%)  number of photon from fiber = 29(photons) Single photoelectron peak (using PMT) Scintillator : 10x40x2mm 3M film 1pe = 13.8 ADCcount pedestal signal Pulse height Example of light yield Number of photoelectron = Pulse height (ADCcount) 13.8 (ADCcount/1pe)

7. Summary of beta-ray test We can see beta-ray signal from scintillator readout MPPC Compare detection (number of pixels or photoelectron) and number of photons from fiber Light detection ability of MPPC is good as PMT for MIP  The way of calculation for light loss from fiber spread is almost good We can say that “signal of 1pixel = signal of 1photonelectron” DeviceFiber dia (mm) # of detection photonelectron # of photon from fiber MPPC1.0mm6.1±0.7 (pixels)28±10 (photons) PMT1.0mm5.8±0.5 (pe)29±6 (photons)

8. Future plan at Niigata Check to number of photon from laser using PMT  Use photon counting PMT (R6353P, R : side on type)  Laser light inject PMT directly  Search 1photonelectron peak Check 1pixel event is certainly from 1photon  1photon laser light inject MPPC UG students are studying SiPM from Russia and MPPC 400pixels (first type)