An improved leakage current compensation technique for a 4πγ ionization chamber system

A current integration method using a small capacitor is most commonly employed for precise measurements of small currents from 4πγ ionization chambers for the secondary standardization of radionuclides. An improved technique has been developed for eliminating the possible effect due to the electrical leakage and/or current loss across the feedback capacitor used in the integration of the ionization current. This method is based upon charge integration from a fixed negative level of potential to nearly the same level of positive potential via the zero point. The validity of this method is demonstrated for some typical applications of 4πγ ionization chamber systems. This technique can contribute to the improvement of accuracy and to the extension of the intensity range of radioactive source in 4πγ ionization measurement.