Measurement of Plutonium Isotopic Compositions in Plutonium Oxide by Thermal Ionization Mass Spectroscopy

The study of the measurement of the plutonium isotopes abundance in the plutonium oxide using the thermal ionization mass spectroscopy (TIMS) is performed in the paper. The conditions such as pretreatment of the plutonium oxide sample, vacuum control of the ion source and analyzer, check of the receiving efficiency of the Faraday cups, the extent control of the signal intensity, the stability control of the signal intensity, the control of the measuring time and so on are optimized. The optimal conditions of pretreatment and measurment are determined, at which the accurate determination of plutonium isotopes components in the plutonium oxide is achieved. Under the selected condition, the plutonium isotopes abundance in the plutonium standard is obtained. Results show that the measuring precisions of the main isotopes ²³⁹Pu and ²⁴²Pu are better than 0.05%(n=6).