A Study of Gamma Unfolding for PB, HC Single Shields and Multilayers Containing PB Shield

The gamma ray spectrum obtained from a 3.7 × 10 4 Bq 252 Cf source after passing through different shielding materials at different thicknesses and different arrangements were detected with a NaI(Tl) detector was fed to a computerized MCA to have a spectrum. This was then stored and subsequently unfolded. The unfolded dose spectra of the fission gamma ray spectrum of the 252 Cf source were also measured for some specific shield thicknesses for all the shielding arrangements studied. Theoretical calculations have been performed to study the characteristics of the above mentioned shielding setups by using the three dimensional Monte Carlo computer code MCNP for fission gamma rays. These are then compared with the experimentally obtained values. The agreement is quite satisfactory. Gamma ray fluxes and corresponding dose values have also been calculated. The purpose of the investigation was to determine the effectiveness of the materials and their multilayers as the gamma ray shielding. It has been found that the materials (single layer and multilayer) studied are very effective as the shield for gamma rays.