Comparison of neutron conversion layers for GaN-based scintillators

In this work neutron-sensitive scintillators based on GaN have been produced by MOCVD. The scintillators consist of GaNepilayers grown on 2 inch double side polished sapphire wafers, with neutron conversion layers on top. Two conversion materials were investigated: enriched LiF and Gd. Undoped and silicon-doped epilayers were examined for their scintillation properties. All of the scintillators showed neutron response when exposed to a thermalized AmBesource, however the LiF produced a peak which is more easily discriminated from the gamma response of the photomultiplier tube. Photoluminescence was used to examine the spectral content of the scintillation light, as well as to study self-absorption of the near-bandedge emission in GaN. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)