Mitigation of Memory Effects in Beta Scintillation Cells for Radioactive Gas Detection

The Automated Radioxenon Sampler/Analyzer (ARSA) developed at PNNL measures the relative concentrations of xenon isotopes using a ?-? coincidence system. Previous tests of the ARSA system have shown that latent radioactivity remains in the plastic cells after evacuation of the gases, leading to a ''memory effect'' in which the background count rate is dependent on the sample history. The increased background results in lower detection sensitivity. Two possible solutions to the memory effect are explored in this work: depositing a thin layer of metal on the plastic cell (''metallization''), and using an inorganic scintillating cell composed of yttrium aluminum perovskite (YAP). In both cases, the presence of inorganic material at the surface is intended to inhibit the diffusion of gases into the cell walls