Investigation of impact of neutron irradiation on properties of InSb-based hall plates

Abstract Hall sensors based on InSb thin film layers are presently being evaluated as one of the options for ITER ex-vessel steady state magnetic sensors. The compatibility with vacuum vessel baking temperature of 220 °C and with the maximum life time neutron fluence of 1018 cm−2 has to be demonstrated. Recently, the InSb Hall sensors with operational temperature up to 350 °C were developed. We investigated stability of these sensors type when exposed to neutron irradiation on experimental fission reactor LVR-15, and during short term post-irradiation temperature cycling. Parameters of the samples were measured before and after irradiation up to the total neutron fluence of 1017 cm−2. Stability of parameters, within a few percents, of the InSb sensors highly doped by Sn was observed. Novel approach to further stabilization of sensors properties based on shielding thermal neutrons and curing the damage caused by fast neutrons by proper annealing was proposed and tested.