Effect of secondary particles with high linear energy transfer on photon beam quality factor

The energy dependence is investigated for a monoenergetic photon radiation quality factor with energies up to 40 MeV, while passing through a thin layer. The conditions of irradiation simulate radiobiological experiments to determine the relative biological eectiveness. The quality factor is calculated on the basis of data on linear energy transfer of all the particles in the irradiated layer, which are calculated using the Monte–Carlo method using GEANT4 code. It has been shown that in considered layers as a result of heavy particles with a high linear energy transfer photon quality factor signicantly (3–15 times depending on the layer thickness) differs from the recommended value of 1.