[A procedure for determining the dose distribution behind block shields. I. A computational method of determining the scatter distribution of a 60Co pencil beam].

The energy dose distribution of a photon pencil beam ray for photons with the primary energy of 1.25 MeV is determined using the Monte-Carlo-method. The found energy dose distribution underlies the calculation of spreading additive-air-ratio for extended 60Co-irradiation fields. The spreading additive-air-ratios, found by the model, show good correspondence with known values from literature.