Comparative study of MOSFET response to photon and electron beams in reference conditions

A comparative study of radiation-sensitive field effect transistors (RADFETs) response to photon and electron beams has been carried out in reference conditions. Both types of beams, routinely used in clinical radiotherapy, have been applied to RADFETs manufactured by Tyndall National Institute. All tests were carried out on RADFETs of several gate oxide thicknesses, sizes and technological processes. Experimental results showed very similar behaviour in terms of sensitivity, linearity and short-term post-irradiation fading with dose ranges typical of clinical radiation treatments. Influence of the temperature has been minimized by biasing RADFETs at zero temperature coefficient drain current during readout process. This novel experimental study shows that analysed RADFETs can be suitable to be used for dose verification in radiation therapies where electron beams are used in intra-operative radiotherapy (IORT).