Development of an Optimized Converter Layer for a Silicon-Carbide-Based Neutron Sensor for the Detection of Fissionable Materials

Abstract

We describe the early stage development of a miniature silicon carbide neutron sensor, for applications including robotic monitoring at the Fukushima Daiichi nuclear power plant, specifically, within the primary containment vessel for fuel debris detection and retrieval. Monte Carlo simulations using MCNP 6.2 and Geant4 10.05.01 are used to investigate and optimize converter layers for thermal neutron detection. Performance of a <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sup> B <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> C:SiC detector system is investigated in detail and a neutron detection efficiency ~4% is predicted, with a gamma discrimination ratio of the order of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> .