The semiconductor γ-ray spectrometer as a neutron flux meter

A new method for measuring the flux densities of thermal and fast neutrons is described. The method is based on measuring the count rates of capture gamma rays produced by neutrons in suitable converters with a high resolution γ-ray spectrometer. Two converters were used in the measurements: a converter for thermal neutrons and a converter for fast neutrons. By performing the measurements with the converter for fast neutrons with a cadmium shield, which absorbs thermal neutrons, and without it, is possible to assess the reliability of the measurements. In the calculation of the flux densities from the count rates a neutron spectrum in air far from a fission source was assumed. The sensitivity of one hour measurements is approximately twice the natural background for thermal and for fast neutrons.