Characterization of a [formula omitted]-[formula omitted] coincidence system comprising a plastic scintillator and HPGe detector for radioxenon measurements under the CTBT.

Measurement of the four relevant radioxenon isotopes, namely 131m Xe, 133m Xe, 133Xe, and 135Xe, play a key role in underground nuclear explosion monitoring for ensuring compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). A β - γ coincidence system that employs a plastic scintillator detector and a HPGe detector was developed in Beijing Radionuclide Laboratory. The Minimum Detectable Activity (MDA) in a 24-h measurement of the system for 131m Xe, 133m Xe, 133Xe and 135Xe can achieve 1.8 mBq, 1.4 mBq, 3.4 mBq and 4.1 mBq, respectively. [ABSTRACT FROM AUTHOR]