Calculation of calibration constants of ionization chambers for gaseous β-emitting nuclides

In determining the concentration of gaseous β-emitters in air with an ionization chamber, the ratio of the energy lost in the chamber as an ionization current to the initial energy of the β-particles must be known. This ratio is called ionization efficiency in this paper. This paper presents the calculation of ionization efficiency by the Monte Carlo method for two types of ionization chamber, parallel plate chamber and cylindrical chamber, filled with air and gaseous β-emitters such as ⁸⁵Kr, ⁴¹Ar, ¹³³Xe, ¹³¹I, ¹³N and ¹⁵O. The results of the calculations for the parallel plate chamber agreed well with those obtained by experiments. The results for the cylindrical one agreed with those by other workers. (author)