A Comparison of the Effects of Neutron and Gamma Radiation in Silicon Photomultipliers

Understand

The effects of radiation damage in silicon photomultipliers (SiPMs) from gamma rays have been measured and compared with the damage produced by neutrons.

• Several types of MPPCs from Hamamatsu were exposed to gamma rays and neutrons at the Solid State Gamma Ray Irradiation Facility (SSGRIF) at Brookhaven National Lab and the Institute for Nuclear Research (Atomki) in Debrecen, Hungary.
• The gamma ray exposures ranged from 1 krad to 1 Mrad and the neutron exposures ranged from 10$^8$ n/cm$^2$ to 10$^{12}$ n/cm$^2$.
• The main effect of gamma ray damage is an increase in the noise and leakage current in the irradiated devices, similar to what is seen from neutron damage, but the level of damage is considerably less at comparable high levels of exposure.