IM2  Innovative radiation detection devices

Sunday, Nov. 1  11:15-12:00  Pacific Salon 3

Session Chair:  Abdallah Lyoussi, CEA / French Atomic Energy Commission, France

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(11:15) IM2-1, Silicon-Carbide based Neutron Detectors for Nuclear Reactor Monitoring

L. Otaviani

IM2NP - UMR CNRS 7334, University Aix Marseille, Marseille, France

Silicon carbide (SiC) is a wide band gap semiconductor which becomes an attractive material for the conception of nuclear detectors. Indeed, compared with classical semiconductors, SiC detectors appear to be very resistant to the radiation-induced damage. In the framework of the European project I-SMART, we developed three types of thermal and fast neutron detectors, all based on ion implantation of 10B as Neutron Converter Layer. The choice of Boron isotope 10 is explained by the relatively high thermal neutron cross section (3900 barns). Mechanisms for detecting neutrons are based on indirect methods where neutrons interact with 10B nucleus to produce charged particles (4He and 7Li nuclei). These charged particles lose energy in the detector and create a generation current of electron-hole pairs. In order to collect the electron-hole pair a p-n junction has been realized. To validate devices, current-voltage measurements have been performed before and after irradiation. The detectors have been tested under thermal neutron irradiations at room temperature in SCKCEN facilities, and under fast neutron irradiations at high temperature in KIT facilities (see Fig.1). Analyses reveal that SiC detectors, under irradiation and at elevated temperature, respond to neutrons showing consistent counting rates as function of external reverse bias voltages and radiation intensity. The counting-rate of the thermal neutron-induced peak increases with the area of the detector, and appears to be clearly linear with respect to the power of the nuclear reactor. The detection of fast neutrons is stable and reproducible up to 500°C.