Testing for Shielding and Estimation of Linear Absorption Coefficient Using Gamma Irradiation of Polymer Composites

Mamta Mainak Saiyad

doi:10.37591/jopc.v10i3.6752

Abstract

The polymer composites were developed for the application of shielding material in a radiation environment. To determine the linear absorption coefficient of the developed materials for neutrons; an experiment was carried out using an Am-Be neutron source of strength ~3 × 107 n/s. The composites of Epoxy polymer were filled with different three fillers; Graphite, Lead, and Boron Nitrided Nanopowder prepared with the same filler content. Transmitted neutrons were detected by Gold (Au) foils using the Neutron activation technique. In this technique, Au foil is activated by Au197(n,γ)Au198 reaction due to neutron interaction. Activated foil is counted for induced 412 keV gammas using a well-calibrated High Purity Germanium (HPGe) Detector. From the foil activity production of Au198 for each thickness of samples and without sample was estimated. The thicknesses of the material were 3 mm, 6 mm, 9 mm, 12 mm, and 15 mm. For each shot, foils were irradiated and counted for 900 seconds. Plot between ln(I0/I) and thickness X and slope of this graph is discussed in the paper which gives the linear absorption coefficient. A graph is plotted between the linear absorption coefficient (μ) for various composites and compared with conventional neutron absorbers & Epoxy polymer (blank) without adding filler. Epoxy/Graphite composition gives a minimum Half Value Layer compared with other composites.