Neutron irradiation effects in LSA oscillators

Four high peak power LSA diode oscillators were exposed to high-energy neutron flux in successive steps. Oscillator failure resulted from a decrease in the diode breakdown voltage to the point that breakdown occurred at threshold for fluences of the order of 10¹⁴neutrons/cm². The reduction in breakdown voltage and an observed frequency increase at a fixed bias can be related to an increase in the diode low field resistance which results primarily from neutron induced carrier removal.