Scintillation Cocktail Optimization for 14C Dating Using the Packard 2000CA/LL and 2260XL

Abstract

In terms of both quenching and, in particular, counting efficiency, scintillation counters employing burst counting circuitry are sensitive to changes in scintillant concentration. Our research demonstrates that there are plateau regions where neither parameter is significantly influenced by moderate changes in a cocktail containing butyl PBD and bis MSB. One of these, consisting of butyl PBD 2.8mg.g-1 and bis MSB 3mg.g-1 of benzene is recommended for these counters, as it enables open window counting efficiencies of ca 90% while exhibiting optimal resistance to quenching. A method for accurate dispensing of such small weights is also described.