Scintillation Counter Performance at the SMU Radiocarbon Laboratory

Abstract

Results are presented of a study of counter performance and vial characteristics for three liquid scintillation counters used at the SMU Radiocarbon Laboratory: the Intertechnique LS20, Packard Tri-Carb 460C, and LKB Wallac Rack Beta 1217. Modifications to photomultiplier tube high voltage, pre-amplifier gain, energy window settings, counting vial design, and sample holder design have resulted in reduced background, higher counting efficiency, and greater long-term stability for the Intertechnique and Packard counters. Square quartz counting vials are used in the Intertechnique and Packard counters with excellent results. Use of Teflon vials in the LKB counter requires careful cleaning procedures and long counting times.