Development of a fast neutron spectrometer based on a plastic fiber array

Abstract

A three-dimensional position-sensitive fast neutron spectrometer is designed to measure fast neutron spectrum over 10 MeV. The detector consists of a 16 $$\times $$ 16 mutually perpendicular plastic scintillation fiber array coupled to $$2 \times 2$$ Hamamatsu H8500C position-sensitive photomultiplier tubes by optical fibers. The fiber array is fabricated with 0.5 mm $$\times $$ 3 mm fibers and 3-mm square fibers. Due to the combined application of different sizes of fibers, the detector can broaden energy dynamic range and meanwhile have good detection efficiency. The method of the combined application of different sizes of plastic fibers in the array may provide a solution to measure wider energy range of solar neutrons. In this paper, we used FLUKA to simulate the performance of the detector model and report the results of experimental studies with neutrons from a pulsed D-T neutron.