Thermoluminescence in CaF₂:Dy and CaF₂:Mn induced by monoenergetic, parallel beam, 81.0 MeV diffracted neutrons

The thermal neutron thermoluminescence response of CaF₂:Dy (TLD-200, 0.35% wt Dy) and CaF₂:Mn (TLD-400, 2% wt mn) have been measured by exposure to a monoenergetic, parallel beam of 81.0 MeV neutrons from a Kandi-II diffractometer. The TL dosemeters were rectangular and of 0.165*0.165*0-83 cm dimensions. The thermoluminescent response of both materials is both theoretically and experimentally shown to be composed of a thermal neutron induced prompt gamma component (approximately 20%) as well as the major component due to the thermal neutron induced beta decay of ¹⁶⁵Dy and ⁵⁶Mn. It is pointed out that the thermal neutron thermoluminescent response of both materials is size and geometry dependent.