Performance of the Packard Tri-Carb(R) 2770TR/SL Liquid Scintillation Analyzer for 14C Dating
liquid scintillation methods
MetadataShow full item record
CitationPasso, C. J., Anderson, R., Roberts, D., & Cook, G. T. (1998). Performance of the Packard Tri-Carb(R) 2770TR/SL liquid scintillation analyzer for 14C dating. Radiocarbon, 40(1), 193-200.
DescriptionFrom the 16th International Radiocarbon Conference held in Gronigen, Netherlands, June 16-20, 1997.
AbstractWe present results that demonstrate the potential of the Packard Tri-Carb(R) Model 2770TR/SL for radiocarbon dating. For 2 g of sample benzene, a stable background count rate of 0.307 cpm and a stable counting efficiency of 64.78% were determined using a 13-75 keV counting window. Changes to the mathematical routines for t-SIE (quench indicating parameter) calculation and a reduction in the activity of the external standard have enabled stability of the t-SIE to be achieved, and combined with the use of a suitable balance point counting window; all of these factors give the stability of performance required for 14C dating. Calculations based on the above parameters indicate that the limit of detection for 2 g samples, counted for 5000 min, is <48,900 yr BP. The great advantage of this system is that these data were acquired using inexpensive standard 7-mL low potassium borosilicate glass vials. Vial holders manufactured from BGO reduced the background to 0.15 cpm with a minimum effect on efficiency (64.46% for 13-75 keV). A similar calculation of the limit of detection gave >51,700 BP. The use of the BGO vial holders in other instruments employing time-resolved liquid scintillation counting (TR-LSC) (Models 2250CA and 2260XL) also brought about significant improvements in detection limits.