Changes of GaAs neutron detectors properties after fast neutron irradiation

One of steps in the development of semi-insulating (SI) GaAs neutron detectors is study of radiation resistance to exposure of the detectors with high fluencies of neutrons (from 5 times 10¹¹ n.cm^-2 to 1 times 10¹⁵ n.cm^-2). Changes in spectra of ²⁴¹Am and ³⁷ Co gamma radionuclide sources, measured by GaAs detectors exposed to various neutron fluencies, are observed. The energy resolution is improving with rising neutron fluency but charge collection efficiency decreased. It is probably caused by the impacting neutrons, which created new lattice defects in the material of detector. The newly created defects would partially compensate original defects, present in the material from the fabrication. However, at higher neutron fluencies a great degradation of detection performance of measured detectors occurred