ESTIMATION OF THE GAMMA-RAY FIELD IN AIR FROM RADIOACTIVE SOURCES IN THE GROUND BY NUMERICAL SOLUTION OF THE BOLTZMANN TRANSPORT EQUATION.

Gamma-ray field in air from radioactive sources uniformly distributed in the ground is calculated by numerically solving the photon transport equation. The scattered flux is developed on the Legendre polynomials basis of the spherical harmonics method and a double P1 approximation is applied. The method is implemented in the Octave programming package.