Abstract - The self-attenuation correction coefficients (Csa) for 137Cs counting in twelve soil samples were determined by MCNP simulation of a high purity germanium detector (HPGe). The correction coefficients were defined as the simulation and experimental efficiency ratio for gamma radiation with 661.66keV. The experimental efficiency of the detector for 661.66 keV of gamma energy in soil samples was obtained using the IAEA reference materials. The exact gamma radiation efficiency for soil samples was calculated on the correct height and soil density using the MCNPX simulation code. The result of the measurements, including the self-attenuation correction coefficient, was compared with the given value and indicates an increase in accuracy.
