Advanced Materials and Algorithms for Radiation Detection

We aim to demonstrate the operation of a highly efficient direct thermal neutron detector using isotopically enriched icosahedral Boron Arsenide (B12As2) semiconducting thin film-based device. Schottky and PN junctions using p-type B12As2 thin films are proposed to evaluate the feasibility of our approach. Alpha particles generated as the result of the transmutation reaction of thermal neutrons with 10B are absorbed within the material, producing electron-hole pairs that are readily collected in the diode structure, hence achieving direct neutron detection. Phase I of this proposal will demonstrate 1 micron thick films of isotopically enriched B12As2 prepared by chemical vapor deposition as proof of principle demonstration. Our simulation indicates that 1 μm thick devices will yield efficiency of ~ 4%, similar to that obtained using planar silicon diodes with a 10B conversion layer, but without any gamma interaction. Phase I will also investigate methods to control carrier concentration to <1016 cm-3. Future efforts will focus on thicker films. Our simulations show that efficiencies as high as 80% are expected for 50 microns thick B12As2 films.