Gamma-insensitive fast neutron detector with spectral source identification potential

A neutron scintillation detector based on high-pressure ⁴He has been developed and tested. The detector responds to elastic scattering of unmoderated fast neutrons, preserving neutron energy, position, and timing information. Neutrons from three different sources, AmBe, ²⁵²Cf, and from the ambient background, have been measured with clearly distinct energy spectra. Exposing the detector to different levels of gamma radiation up to 1 mSv/h from a ⁶⁰Co source has demonstrated that gamma exposure does not affect neutron detection performance within measurement statistics. Applications in the field of radiation portal monitoring are discussed.