GEANT4 based Monte Carlo simulations have been carried out for the
determination of efficiency and conversion factors of a gas-flow ionization
chamber for beta particles emitted by 86 different radioisotopes covering the
average-b energy range of 5.69 keV-2.061 MeV. Good agreements were found
between the GEANT4 predicted values and corresponding experimental data, as
well as with EGS4 based calculations. For the reported set of b-emitters, the
values of the conversion factor have been established in the range of
0.5?1013-2.5?1013 Bqcm-3/A. The computed xenon-to-air conversion factor
ratios have attained the minimum value of 0.2 in the range of 0.1-1 MeV. As
the radius and/or volume of the ion chamber increases, conversion factors
approach a flat energy response. These simulations show a small, but
significant dependence of ionization efficiency on the type of wall material.
Erratum: Monte Carlo study of ionization chamber magnetic field correction factors as a function of angle and beam quality. [Med. Phys. 45(2) p. 908‐925 (2018)]