Polyester Composite Thermal Neutron Scintillation Films

Novel $^{6}{\rm Li}$ -loaded polyester scintillation films have been designed and fabricated to detect thermal neutrons. Lithium fluoride crystals containing enriched $^{6}{\rm Li}$ were synthesized and integrated into polyethylene naphthalate polyester matrix containing appropriate luminescent molecules. Thermal neutron capture by $^{6}{\rm Li}$ ions produces charged particles with kinetic energy sufficient to ionize and subsequently excite the components of the polymeric matrix. This energy is transferred to secondary luminescent molecules, which produce net radioluminescence responses detectable by a photomultiplier tube. Design, production and characterization of these scintillation films are discussed herein. The films due to their thinness $(< 220 \mu{\rm m})$ and low atomic number components have low susceptibility to gamma induced scintillation and thus are effective discriminators for thermal neutrons.