A scintillation counter for the assay of radioactive gases

A glass chamber, with a plastic scintillator serving as one wall, may be used to assay gaseous samples of weak β-emitting nuclides (notably 14 C). The specific activities of duplicate samples can be reproduced to ±0.5%. Since the observed counting rate of an active gas sample is independent of gross impurities and the chemical form of the nuclide, sample preparation is simpler and faster than for other gas-counting methods. The scintillation counter assembly can be readily adapted to the assay of both liquid and solid samples; the method described for liquid assays has certain advantages over existing methods.