  GaAs Schottky diode detectors have been fabricated upon Low Pressure Vapour
Phase Epitaxial GaAs. The devices were characterised before and after a $1.25
\times 10^{14}$~cm$^{-2}$ 24GeV/c proton fluence. The as fabricated Ti-GaAs
barrier height was measured, via two electrical methods, to be $0.81\pm0.005$
and $0.85\pm0.01$~eV and a space charge density of $2.8 \pm 0.2 \times
10^{14}$~cm$^{-3}$ was determined. The current was greater than that expected
for an ideal barrier with the excess attributed to generation current from the
bulk. The charge collection efficiency, determined from front alpha
illumination and 60 keV gamma irradiation, was inexcess of 95% at 50V reverse
bias. After irradiation the reverse current, measured for a bias of 200V at
20$^{o}$~C, increased from 90~nA to 1500~nA due to radiation induced generation
centres. Deep levels were showed to be present using capacitance techniques.
The charge collection of the device determined from front alpha illumination
fell to $32\pm5$% at a reverse bias of 200V.
