Radiation damage studies of amorphous-silicon photodiode sensors for applications in radiotherapy X-ray imaging

摘要

The high radiation tolerance of hydrogenated amorphous silicon (a-Si:H) is one reason it has become a candidate for high-energy physics applications and for radiotherapy and diagnostic imaging. The performance of 1 [mu]m and 5 [mu]m a-Si:H n-i-p photodiode sensors used in conjunction with Lanex (Gd2O2S:Tb) intensifying screens has been measured as a function of high-energy photon dose. Over the course of irradiation with a 60Co source to a total dose of ~104 Gy the output signal due to the sensor-screen combinations experienced maximum variations of -1.3% and +2.7% for the 1 [mu]m and 5 [mu]m sensors, respectively. Transient effects associated with the sensors and screens are also reported.