Confirmation of Track Formation in Cellulose Nitrate Detector by Lithium Particles from ¹⁰B(n, α)⁷Li Reaction

Abstract

Two experiments were performed, which confirmed that the lithium particles pro-duced by the ¹⁰B(n, α)⁷Li reactions form etchable latent tracks in cellulose nitrate resin. The first experiment was made on a pair of resin detector plates sandwiching between them a boron-bearing layer. Upon irradiation and etching, the tracks appearing on the two plates were found to constitute matching pairs, some of which appeared to be shorter than others, suggesting their correspondence respectively to the ⁷Li and a particles generated by the ¹⁰B(n, α)⁷Li reaction. This surmise was further confirmed by a second experiment, in which the pairing of etch-pits was examined between the two faces of a film detector of thickness below the range of a but above that of ⁷Li particles. The ratio between paired and single etch-pits counted in a unit area of the two faces of film after irradiation and etching proved to be quite close to the value derived by calculation based on the assumption that 'Li as well as a particles leave etchable tracks on the resin with 100% efficiency, whereas the observed ratio distinctly differed from the correspond-ing calculation undertaken assuming that a particles alone contributed to the track for-mation.
This finding is consistent with the estimations of etchable track formability obtained by applying criteria given in three independent theoretical studies found in published literature.