INVESTIGATION OF GAMMA-RAYSATTENUATION IN METALLIC POWDERS USING GAMMA- GAMMACOINCIDENCE METHOD

Abstract

Gamma-rays attenuation in metallic powders is investigated using coincidence technique with two 3ʺx3ʺ NaI(Tl) scintillation detectors. Na-22 source isused with 0.4µCi activity and resolving time registered was 6.7 ns. Linear attenuation coefficient (L.A.C) measurements were carried out at 511keV energy for Fe3O4 and ZrSiO4 metallic powders with uniform 100µm grains size and Fe sheets locally available (for comparison) with different thicknesses. The L.A.C values (in cm-1) calculated from direct spectra were 0.2705, 0.2641and 0.6239 for the materials respectively. The L.A.C values calculated from coincidence spectra using net peak area NPA were 0.2363, 0.2152 and 0.6231 and with using gross peak area GA were 0.2092, 0.1974 and 0.5261 respectively. The mass attenuation coefficient M.A.C (in cm²/g) for Fe sheets from direct spectra was 0.0792 and from coincidence spectra was 0.0791 and 0.0660 for NPA and GA respectively. The ratio of L.A.C from coincidence spectrum / L.A.C from direct spectrum were 0.7733, 0.7474 and 0.8432 using GA and 0.8735, 0.8148 and 0,9987 using NPA respectively.