Gamma Ray Fields in the Air Due to Sources in the Ground

Abstract

Air kerma per unit source density at 12 heights up to 300 m above the ground was calculated using a Monte Carlo method for monoenergetic plane sources in and on the ground and for natural radionuclides uniformly distributed in the ground. In the case of plane sources, calculations were performed for 18 photon energies from 10 keV to 5 MeV and for 22 source depths expressed in mass per unit area ranging from 0 to 200 g.cm^-2. For natural nuclides, the whole lines compiled in a recent nuclear data file were taken into account. Double differential photon fluences in air with respect to energy and incident angle were also calculated for all cases, and the general features were discussed. The influence of soil composition upon air kerma was investigated for two different kinds of soil.