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)
Top Related