Gamma-Ray Scattering by Concrete Surfaces

Gamma radiation from point sources of cobalt-60 (1.25 Mev) and iridium-192 (0.4 Mev) was scattered from a concrete surface. Dose rates were measured at heights equal to source heights, as a function of the ratio of height to separation distance. The percent of scattered to direct radiation rises to a maximum of 12% at h/d = 0.10 for cobalt-60, and a maximum of 20% at h/d = 0.15 for iridium-192. These results are shown to agree with other work and with Monte Carlo calculations.