Study of parameters influencing the response of RADFETs

Fraunhofer INT together with CERN calibrated different RADiation-sensitive Field-Effect Transistor (RADFET) radiation dosimeters from two vendors to be operated in CERN's RadMON system with Co-60 gamma radiation to monitor total ionizing dose (TID) at CERN accelerators [1]. The aim of this study was to find out which RADFET type was best suited for the RadMON system and what parameters influence the radiation-induced threshold voltage shift of the pMOS transistors most. Therefore we looked at the sensor response while changing doserate, reading conditions, package, lot-to-lot variation during irradiation. In addition CERN previously examined the effects of different particle or radiation types on their response [2]. Compared to former measurements we reached excellent accuracies which guarantees good dose sensitivity during application at CERN. Additionally the findings of this study can also be of interest for those who will use RADFETs in space or other radiation environments as dosimeters.