THE EFFECTS OF RADIATION ON GALLIUM-ARSENIDE RADIATION DETECTORS

Semi-insulating, undoped, Liquid Encapsulated Czochralski (SI-U LEG) G aAs detectors have been irradiated with 1 MeV neutrons, 24 GeV/c proto ns, and 300 MeV/c pions. The maximum fluences used were 6 x10(14), 3 x 10(14), and 1.8 x10(14) particles/cm(2), respectively. For all three t ypes of irradiation, the charge collection efficiencies (cce) of the d etector are reduced due to the reduction in the electron and hole mean free paths. Pion and proton irradiations produce a greater reduction in cce than neutron irradiation, with the pions having the greatest ef fect. The effect of annealing the detectors at room temperature, at 20 0 degrees C and at 450 degrees C with a flash lamp have been shown to reduce the leakage current and increase the cce of the irradiated dete ctors. The flash-lamp anneal produced the greatest increase in the cce from 26% to 70% by increasing the mean free path of the electrons. Tw o indium-doped samples were irradiated with 24 GeV/e protons and demon strated no improvement over SI-U GaAs with respect to post-irradiation cce.