Transparent lithiated polymer films for thermal neutron detection

• A transparent polymer scintillator containing 3.85 wt% 6Li has been synthesized.
• This class of polymeric thermal neutron scintillation detector is water-soluble.
• Salicylic acid, presumably in the form of lithium salicylate, is used as a fluor.
• The material emits 373 photons/α (241Am) and an average of 139 photons/β (36Cl).
• The material emits 360 photons per thermal neutron capture event.

Novel water-soluble 6Li loaded copolymer scintillation films have been designed and fabricated to detect thermal neutrons. Styrene and maleic anhydride were copolymerized to form an alternating copolymer, then the anhydride functionality was hydrolyzed using 6Li hydroxide. The resulting poly(styrene-co-lithium maleate) was mixed with salicylic acid as a fluor and cast as a thin film from water. The maximum 6Li loading obtained that resulted in a transparent film was 4.36% by mass (6Li to polymer). The optimum fluorescence output was obtained for 11.7% salicylic acid by mass, presumably in the form of lithium salicylate, resulting in an optimum film containing 3.85% by mass of 6Li. A facile and robust synthesis method, film fabrication protocol, photoluminescence results, and scintillation responses are reported herein.