Calibrating p-i-n Diodes for Displacement Damage Monitoring in a Space Radiation Environment

This work investigates the response of specially developed silicon p-i-n diodes with a long base as sensors to measure displacement damage dose (DDD) in silicon. Measurements of DDD are based on the forward voltage shift ( $\Delta V_{F}$ ) of irradiated p-i-n diodes. In this work, the p-i-n diodes were irradiated in the following radiation fields: 1) 20-MeV electrons from a medical linear accelerator (LINAC); 2) 200-, 150-, and 100-MeV protons at the Groningen proton therapy facility; and 3) 4.63- and 15.3-MeV quasi-monoenergetic neutrons at the Czech Technical University, Prague. It was demonstrated that the calibration factor ( $\alpha $ ), which is the response of the p-i-n diode in terms of DDD obtained using 20-MeV electrons, can be used to predict the p-i-n diode response for protons and neutrons as mentioned above (within experimental error). However, the p-i-n diode response related to 100-MeV protons has a 70% higher response than predicted, which requires further investigation. Overall, the 20-MeV electrons from a medical LINAC were found to be suitable for p-i-n diodes calibration in terms of the non-ionizing energy losses (NIELs) and are widely available in contrast to 1-MeV electrons, fast neutrons, and protons.