MONTE-CARLO CALCULATIONS OF MONOENERGETIC ELECTRON DEPTH-DOSE DISTRIBUTIONS IN LIF CHIPS - SKIN DOSE CORRECTION FACTORS FOR BETA-RAYS

Monte Carlo calculations have been carried out for monoenergetic elect rons from 0.1 to 4 MeV irradiating LIF chips in both perpendicular and isotropic geometry. This enabled the calculation of skin dose correct ion factors (beta factors) for typical beta energy spectra as measured with a beta-ray spectrometer at CANDU nuclear generating stations. Th e correction factors were estimated by averaging the depth dose distri butions for the monoenergetic electrons over the experimentally measur ed beta-ray spectra. The calculations illustrate the large uncertainty in beta factors arising from the unknown angular distribution of the beta-ray radiation field and uncertainties in the shape of the beta-ra y spectra below 500 keV.