Post on 18-Jan-2016
description
Radiation damage of 1600Pixel MPPC by neutrons
ILC-CAL meeting
University of tsukuba
H.Yamazaki
Dose rate
Flux = 1.5×109 neutron/cm2/Wh (W = watt, h = hour)
…… calculated MCNP ( Monte Carlo Neutron
and Photon Transport Code System ) Code
4 dose rate patterns ↓1.5×109 neutron/cm2 /Wh×12.5/60 h×1W =3.125×108 neutron/cm2
1.5×109 neutron/cm2 /Wh×12.5/60 h×10W =3.125×109 neutron/cm2
1.5×109 neutron/cm2 /Wh×12.5/60 h×100W =3.125×1010 neutron/cm2
1.5×109 neutron/cm2 /Wh×12.5/60 h×1kW =3.125×1011 neutron/cm2
Uniformity of Sample (Noise Rate,Cross-talk Probability )
The individual difference of several percent was confirmed to four samples.
Sample irradiated with 3.125×108 n/cm2
Sample irradiated with 3.125×109 n/cm2
Sample irradiated with 3.125×1010 n/cm2
Sample irradiated with 3.125×1011 n/cm2
Cross-talk Probability Noise Rate (Vbias)
Noise Rate (Vover )
Measurement after the irradiation
Noise Rate Cross-talk Probability
(at Vbias = -77.5V) before 108 n/cm2 109 n/cm2
NoiseRate(Hz) 346,236 569,263 3,157,690 Increased of Noise Rate 160% 910%Crosstalk probability 0.158 0.144 0.171
Noise Rate rises as dose rate goes up,Cross-talk dose not change so much by irradiation
Before the irradiation3.125×108 n/cm2
3.125×109 n/cm2
Before the irradiation3.125×109 n/cm2
3.125×109 n/cm2
Measurement after the irradiation ( 3.125×108 n/cm2)
Noise Rate Cross-talk Probability
several times measurement after irradiation
2007 11/14 Before irradiation 11/16 Just after irradiation 12/05 Before annealing at 60 ゜ C 12/06 After annealing at 60 ゜ C 12/15 The additional measurement 1 12/15 The additional measurement 2
Measurement after the irradiation ( 3.125×109 n/cm2)
Cross-talk Probabirity Noise Rate
several times measurement after irradiation
2007 11/14 Before irradiation 11/16 Just after irradiation 12/05 Before annealing at 60 ゜ C 12/06 After annealing at 60 ゜ C 12/15 The additional measurement 1 12/15 The additional measurement 2
Summary• Noise Rate rises as dose rate gose up• Cross-talk dose not change so much by irr
adiation• There are some problems for the noise rate
measurement
Plan Another analysis
…….Gain,NoiseRate(Vbias correction),After Pulse
Back Up
Noise Rate (Reference)