GaAs detectors with LiF layer for detection of thermal neutrons

Our SI (semi-insulating) GaAs detectors were successfully modified by 6LiF converter layers to detectors of thermal neutrons. The first spectra measured by these detectors, when irradiated by neutrons from 239Pu–Be source moderated by polyethylene, show the evidence of 6Li (n,α) 3H reaction. Parallel detection of neutrons with gammas from the source was suppressed by adjusting the detector active area depth by bias voltage applied. The influence of the surface density of the converter layer on the current–voltage characteristics of the investigated detectors is presented as well. The results show that higher surface density of 6LiF layer reduced the reverse current more considerably than the lower one, when comparing with the detector without any coating.