ANGULAR ENERGY FLUX OF SECONDARY GAMMA-RAYS IN MATTER: SMALL-ANGLE SCATTERING FROM A POINT ISOTROPIC SOURCE

Abstract

The distribution in energy and angle of secondary gamma-rays in matter is studied, with particular reference to small angles and to energies near the incident energy. The "angular energy flux" arising from a point isotropic source in matter is calculated, using small-angle approximations, and compared with experimental data obtained for a Cs137 source in concrete. It is concluded that for small angles and for energies near the incident energy, only a few orders of scattering contribute to the angular energy flux out to considerable thicknesses, whereas for large angles and low energies many orders of scattering contribute even for small thicknesses.