Accurate method for neutron fluence control used in improving neutron-transmutation-doped silicon for detectors

摘要

Abstract: Neutron transmutation doping (NTD) of silicon (Si) in nuclear reactors is known as a successful way of obtaining high-quality material for power devices. Using NTD of Si in order to obtain high-quality material for detectors requires an accurate neutron fluence control. The paper presents results obtained in this field using silicon slices as neutron calibration material. Irradiation was done in a vertical channel of the VVR-S nuclear reactor in Bucharest, Romania. Final resistivity of slices used for calibration was between 20 and 50 ohm $MUL cm. Special attention was paid to the accuracy of initial and final characterization of the slices concerning resistivity, lifetime, and defects, as well as to the neutron fluence calibration and control used during exposure. High-performance detectors were obtained using this material.!