Computational and experimental determination of slow neutron flux by using Li-6 foil and nuclear track detector

Abstract

In the present study, slow neutron flux was determined with an experimental method based on 6Li(n, t)4He reaction. 6Li coated foils were mounted on track etch detectors without any gap and they were irradiated with an Am–Be neutron source for 6 h. The track detectors were affixed on a polyethylene plate which has a thickness of 2.0 cm for neutron moderation. Following irradiation, the track detectors were etched, the tritium tracks were counted with an in-house developed track counting system, and the total number of reactions was computed. The difference in particle ranges and track diameters on the Cr-39 detector allowed for the precise distinguishing of tritium, alpha, and neutron particles. The neutron spectrum at the 6Li coated foil position was simulated with MCNP5 using Evaluated Nuclear Data File (ENDF) cross sections of 6Li(n, t)4He reaction. The total reaction numbers obtained with experimental and computational methods are compatible with each other.