Thin target neutron yield for Li(p,n) reaction with thick Ta target as stopping material

Abstract

The neutron spectral yields from the Li(p,n) reaction has been considered as an important study due to its potential use as mono-energetic fast neutron source. This reaction has been studied at energies nearing Coulomb barrier for mono-energetic neutrons from 7Be ground state emissions and at energies beyond few tens of MeV to get the quasi mono-energetic fast neutrons, depending on their specific applications such as cross section studies, calibration of neutron detectors, etc. However, the number of measurements at proton energy of 8–20 MeV is sparse in the literature. In this energy range, the mono-energetic neutrons are strongly interfered by emissions from other excited states distorting the emission neutron spectra. Majority of the earlier measurements were carried out using carbon as the backing material during evaluation of neutron yields to minimize the interference of neutrons from the backing material. Here, a commonly used thick Ta target was explored as the backing material for the thin Li target and the neutron yields were measured with solid polymeric neutron track detector, CR-39. This is a passive technique and does not require any associated instrumentation during the irradiation process. This work presents the estimation of thin target neutron yields from Li target by subtracting the neutron yields contributed by the supporting material (Ta), which was separately measured in the same physical conditions.