The Backscattering of Gamma Radiation from Spherical Concrete Walls

The Monte Carlo technique has been applied to investigate the effect of wall curvature on the backscattering properties of concrete. The wall was considered infinitely thick and the source radiation was normally incident. Monte Carlo calculations were only performed at 1 Mev source energy but an analytical formula was derived to facilitate extrapolations to other energies as well as materials. The results show that for practical purposes the plane wall albedo is a sufficient, and conservative, approximation, 90% of its value being reached at a concrete wall radius of about 100 cm for source energies up to 10 Mev.