Alpha-spectrometry by radiation-degraded semi-insulating GaAs detectors

A radiation hardness study of semi-insulating GaAs detectors against 5 MeV electrons is presented in this paper. The influence of cumulative dose in the range from 136 up to 2000 kGy on alpha-spectrometry of 241Am is evaluated for investigated detectors. The characterising parameter, the charge collection efficiency, was negatively affected by cumulative dose applied. At 200 V detector reverse bias it rapidly decreased from initial 45% it to 15% at 600 kGy proceeding with mild deterioration down to 6% at2000 kGy. The operability of detector was well preserved through whole range of doses. The alpha- and gamma-spectrometry of the same radioactive source are compared.