An inexpensive method for the acquisition of external standard quench correction capability

A simple and economical method of acquiring external standard quench correction capability for liquid scintillation counters is described. The technique utilises a commercially available, weak (< 1 μCi) 137Cs source, sealed in glass and used in conjunction with a flat-bottomed, 55 x 15 mm glass tube positioned in the centre of the conventional 20 ml scintillation vial. Each sample is counted with and without the 137Cs source in place and the counts added by the external standard are analysed in two channels. The external standard channel ratio and external standard gross counts so obtained have been found to be linearly related to 14C counting efficiency for both chemical and colour quenched samples. (author)