Methods of Calculating the γ-Radiation Absorbed Dose Rate in Case of Radioactive Contamination of Meadow Biogeocenoses

The absorbed dose rate of external gamma-radiation from two sources of radiation - surface soil layer and subsurface phytomass of plants in stand grass - is calculated by different methods. The calculation of the absorbed dose rate based on integration of the dose attenuation function of a point source taking into account the dose accumulation factor was compared with the results of a Monte Carlo solution of the radiation transfer equation (MCNP5 code system). The obtained results show that the absorbed dose rate of external gamma-radiation in the air-plant medium can be calculated by integrating the dose attenuation function of a point source with variable radionuclide activity and biometric parameters of the plants.