Development of hydrogenated amorphous silicon sensors for high energy photon radiotherapy imaging

Measurements with a high energy radiotherapy photon beam have been performed on photosensitive n-i-p diodes fabricated from hydrogenated amorphous silicon. Such photodiodes can be configured into large two-dimensional arrays of addressable sensors suitable for real-time imaging of megavoltage treatment beams, as well as other applications such as diagnostic x-ray imaging. Signal data for a number of different diode configuration in a 6 MV photon treatment beam are presented. These measurements are presented as early results of an on-going examination of the signal properties of a-Si:H photodiodes for medical imaging applications