Silicon photo-multiplier radiation hardness tests with a beam controlled neutron source

Radiation hardness tests were performed at the Frascati Neutron Generator on silicon Photo-Multipliers that were made of semiconductor photon detectors built from a square matrix of avalanche photo-diodes on a silicon substrate. Several samples from different manufacturers have been irradiated, integrating up to 7×1010 1-MeV-equivalent neutrons per cm2. Detector performance was recorded during the neutron irradiation, and a gradual deterioration of their properties began after an integrated fluence of the order of 108 1-MeV-equivalent neutrons per cm2 was reached.