Minimizing the amount of scintillator in liquid scintillation counting

Modern liquid scintillation instruments have photomultipliers with a high sensitivity over a broad spectral range and a coincidence circuit with puls summation. These lead both to a reduction of the counting volume and to a measurement using 1:1 diluted scintillator cocktails. The volume reduction is possible up to 5 ml in normal 20 ml vials or below 2 ml by hang in of a 2 ml polyethylene ampulla. The counting efficiency ranges from 75% to 96% depending on the counter model and the measuring conditions. (author)