Development of a large-volume fast-neutron detector for environmental neutron monitoring

We report development of a 20-liter large-volume detector based on a 0.5 % gadolinium-loaded liquid scintillator. This detector is designed for the both monitoring the flux and the energy of fast neutrons. The detector with a compact size and portable electronics can be used in the field for the fast-neutron monitoring. The calibration and the performance of the detector were studied by using a gamma and a ²⁵²Cf neutron source. A good neutron tagging efficiency was obtained and the study showed that the neutron energy, with an electron equivalent energy greater than 230 keV and the neutron flux could be measured simultaneously. We applied the detector to environmental neutron monitoring and to fast-neutron flux measurements.