Development and testing of a Frisch-Grid Ionization Chamber for the measurement of low activity of alpha-particle emitters

A Frisch-grid Ionization Chamber (FGIC) for the measurement of low activity of alpha-particle emitters has been built. The design and performance are described in this paper. According to the Shockley–Ramo theorem and the experiment, the key parameter grid inefficiency was studied in detail. The experimental and calculated values of the correction factor are shown to be in good agreement. In the measurement of the alpha-activities of a 234,238U sample, the detection efficiency was investigated based on the Monte-Carlo method. Considering this influence, the activity of alpha-particle emitters was identified.