New version of library of dose kernels of photons pencil beam and their analytical approximation

A new version of dose kernels library of photon pencil beams for water has been created to calculate a more perfect description and modelling of the physical processes of photons and charged particles' interaction with matter, with more adequate data on the interaction cross sections and significantly lower values of the statistical uncertainties of the results. The library includes data for monoenergetic photons in the energy range of 0.25-19.75 MeV, data for bremsstrahlung photons with a maximum energy of 4.0 MeV, 6.0 MeV, 10.0 MeV, 15.0 MeV, 18.0 MeV, and data for the spectrum of the ROKUS therapeutic apparatus. Dose kernels were calculated using the Monte-Carlo method by the EGSnrc code. Depths in water from 1.0 to 40 cm and along the radius from 0.02 to 46.0 cm were studied. A convenient mathematical approximation model of dose kernel of a pencil beam is proposed.