Radiation damage of amorphous silicon photodiode sensors

The effect of ⁶⁰Co radiation on the leakage current behavior of hydrogenated amorphous silicon photodiode sensors has been investigated. These sensors, with an n-i-p construction, are identical to those used on two-dimensional, pixelated imaging arrays currently under development. Sensor leakage current is reported as a function of dose up to a cumulative dose of ~3×10⁶ cGy. Following the irradiation, the effect of room-temperature annealing on the leakage current was quantitatively studied. Finally, sensor noise measurements prior to and after the irradiation are also reported. The implications of this study for radiotherapy imaging are discussed