CROSS-SECTIONS FOR WATER-VAPOR FOR THE MONTE-CARLO ELECTRON TRACK STRUCTURE CODE FROM 10-EV TO THE MEV REGION

Electron cross-sections were summarized for an accurate simulation of the track structure of high-energy electrons up to a few MeV in water vapour. Elastic scattering was described by the Rutherford formula taking the screening effect into account. Partial and total ionization cross-sections were calculated using Seltzer's formula based on the Weizsacker-Williams method. The total excitation cross-section was evaluated by a so-called Fano plot with parameters given by Berger and Wang. The validity of the cross-sections was examined by comparison with experimental and calculated data. Use of these cross-sections enabled the development of a Monte Carlo track structure code KURBUC encompassing the energy range between 10 eV and 10 MeV. Finally the tracks generated by KURBUC were compared with those generated by MOCA8B in terms of radial distributions of interactions, point kernel and frequencies of energy deposition in small cylindrical targets pertaining to biological macromolecules such as DNA.