Development of methods to track beta-gamma detector gains is important to the accuracy of radioxenon system measurements. Typical gain monitoring and correction is done using a mixed 137Cs/154Eu source, which results in several gamma-ray lines that can be fit by Gaussian distributions, and gain adjustments made to bring the peaks into the expected channel. The beta detector on the other hand does not produce clear peaks, so peaks are made by taking slices from the 2-D Compton scatter line and then analyzed. The method developed at PNNL takes a different approach; it uses the 2-D Compton scatter line and rotates the frame of reference until the projection of the Compton scatter line forms a peak. This method optimizes the use of counting statistics available from the Compton scatter and gives reliable results even with relatively short measurement times.
This work discusses a method under development that will improve nuclear test monitoring and verification by improving the accuracy of radioxenon analysis and will disseminate alternative detector gain stability check that performs well even with low counting statistics.