SCINTILLATING-GLASS-FIBER NEUTRON SENSORS

Cerium-doped lithium-silicate glass fibers have been developed at Paci fic Northwest Laboratory (PNL) for use as thermal neutron detectors. B y using highly-enriched Li-6, these fibers efficiently capture thermal neutrons and produce scintillation light that can be detected at the ends of the fibers. Advantages of scintillating fibers over He-3 or BF , proportional tubes include flexibility in geometric configuration, r uggedness in high-vibration environments, and less detector weight for the same neutron sensitivity. This paper describes the performance of these scintillating fibers with regard to count rates, pulse height s pectra, absolute efficiencies, and neutron/gamma discrimination. Fiber s with light transmission lengths (1/e) of greater than 2 m have been produced at PNL. Neutron sensors in fiber form allow development of a variety of neutron detectors packaged in previously unavailable config urations. Brief descriptions of some of the devices already produced a re included to illustrate these possibilities.