Application of neutron activation analysis to the measurement of isotope abundance shifts in calcium and potassium

A simple method for the measurement by neutron activation analysis of the isotopic abundance shifts of⁴⁴Ca and⁴¹K in compounds of low volatility is described. Extraction and measurement procedures for the radioactive argon isotopes (³⁷Ar,³⁹Ar and⁴¹Ar produced by (n, α) and (n, p) reactions are also given. The results obtained demonstrate that the accuracy for the measurement of δ⁴⁴Ca is better than by the mass spectrometric method; in the case of δ⁴¹K measurement the accuracy is the same as that obtained with the mass spectrometer. Interfering reactions which yield other rare gases, and their relative contribution to the error in the measurement of δ values are also discussed.