Fast Neutron Detection Using Thermoluminescent Phosphors with Internal and/or External Photon Radiators

This work describes the influence of polyethylene radiators on fast neutron relative responses of some thermoluminescent detectors. The studies concentrated mostly on the influence of an international radiator, i.e. mixed inorganic phosphor-polyethylene detectors. The procedure used to prepare such detectors using sufficiently thermally stable polyethylene is described. The reproducibility of such mixed detectors, and the possibilities of re-use and other practical aspects are discussed. Neutron relative responses of such mixed detectors having CaSO4:Dy, CaSO4:Mn, and Al2O3 as thermoluminescent materials were measured in a reactor beam, as well as for 14.7 MeV neutrons. It was found that relative responses increase substantially for the internal polyethylene radiator. For high energy neutrons the response can be increased even more by using an additional external polyethylene radiator. The results obtained are analysed and discussed.