Alpha spectrometry and liquid scintillation counting for the measurement of 238Pu, 239Pu, 240Pu, 241Pu, 242Pu and age

A method for the measurement of the isotopic composition and time since last chemical separation (age) of plutonium is presented. The method includes alpha spectrometric measurement of 238Pu, 239Pu and 240Pu where the ratio of 239Pu and 240Pu was determined using spectral deconvolution, and liquid scintillation counting of 241Pu, after chemical separation of plutonium and americium. For the age determination, the 241Pu determined using liquid scintillation counting was combined with alpha spectrometric measurement of 241Am. The results of the isotopic composition were compared with certified reference materials with known isotopic composition, and the results of the age determination were compared with literature values of the separation dates. •Measurement of plutonium isotopic composition with alpha spectrometry and LSC.•Deconvolution of alpha peaks from 239Pu and 240Pu.•Age determination of plutonium using alpha spectrometry and LSC.