Geant4 simulation of detection efficiency and self-attenuation effect of β particles for radioxenon measurement using β−γ coincidence equipment

Measurement of radioxenon isotopes is one of the key components of the verification regime of the comprehensive nuclear-test-ban treaty. The β−γ coincidence technique is the most sensitive method for radioxenon isotopes detection. The self-attenuation effect of β-particles is unavoidable during β−γ coincidence measurement due to the presence of gas matrixes, such as stable xenon and other carrier gases, in the sample. In this study, the detection efficiencies of β-particles for radioxenon isotopes in different volumes of different gas matrixes (xenon, nitrogen, and helium) were simulated using Geant4 and the self-attenuation effects were deduced accordingly. The method to correct for the self-attenuation effects was thereby provided.