Stilbene cell development to improve radioxenon detection

A prototype stilbene beta cell has been designed, manufactured, tested, and compared to a plastic scintillator beta cell used for nuclear explosion monitoring of radioxenon. Measurements of the four isotopes of interest show similar responses for both the plastic scintillator and stilbene cell. However, we show that the stilbene cell exhibits 100-times smaller memory effect than the plastic cell, a capability that is of interest in nuclear explosion monitoring because it improves detection sensitivity, allowing for decreased time between measurements. The resolution of the stilbene cell is improved slightly (decreased by 2.2 keV at 129 keV) when compared to the plastic scintillator cell. The efficiency of the stilbene cell is lower than that of the plastic by an average 15%. These results suggest that the light-collection efficiency of the stilbene cell could be improved in future designs. Pulse shape discrimination analysis decreases the minimum detectable concentration by 1%. The use of this geometry allows for a simple replacement of the plastic cells currently used in the field versus a complete overhaul of the existing radioxenon monitoring stations.