Air-ground interface correction factors for gamma emitters in air.
For isotropic point photon sources above an air-ground interface, the spectral energy fluences at the ground have been calculated by the Monte Carlo method for source energies in the range 50 keV-10 MeV. The source heights and the horizontal source-detector distances varied from 0.05 to 5 mean free paths in air. Air-ground interface correction factors have been calculated and then analytically approximated. The greatest deviations from unity were found for 100-keV sources located on the ground. Near the source, kerma free in air is enhanced by 30%, and far from the source it is reduced by a factor of 3.
D000398:Air Pollution, Radioactive; D003037:Cobalt Radioisotopes; D004781:Environmental Exposure; D005720:Gamma Rays; D009010:Monte Carlo Method; D011868:Radioisotopes
D003037:Cobalt Radioisotopes; D011868:Radioisotopes