An alternative method for chronometric determinations involving curium

Abstract

A method for quantifying ratios of isotopes of plutonium (Pu), americium (Am), and curium (Cm) using inductively coupled plasma mass spectrometry (ICP-MS) is described that does not require radiochemical separations or a chemical yield monitor. This approach provides more rapid analysis, which is important for chronometric applications related to nuclear forensics analysis. To demonstrate its utility, we used it to quantify the ingrowth 240 Pu (t 1/2 ¼ 6563 years) from 244 Cm (t 1/2 ¼ 18.10 years) in a solution of unknown "age" (e.g. time since last separation). Results are compared to similar samples for which the time since separation was known. In addition, alpha spectrometry was used to validate the ICP-MS measurements. In this case, 238 Pu and 241 Am were used as chemical yield monitors for 240 Pu and 244 Cm, respectively. The relative standard deviation for the isotope ratio method using ICP-MS was slightly greater than the traditional radiometric approach, but sufficient for this application. Measured activity ratios of 240 Pu and 244 Cm provided an age for the unknown sample that linked it to research activities involving the production of curium isotopes for thermoelectric heat sources during the late 1970's.

Plasma source mass spectrometry for radioactive waste characterisation in support of nuclear decommissioning: a review

“…To date, there are no reported applications of ICP-MS for Cm or Cf measurement in nuclear wastes. Kurosaki et al (2014) reported the measurement of 243 Cm, 244 Cm, 245 Cm, 246 Cm and 240 Pu using a Thermo Finigan Element 2 for nuclear forensics applications. 310 Gourgiotis et al (2010) used ICP-QMS (Thermo Electron X-series) for Cm and Cf isotope measurement in transmutation studies.…”

“…Kurosaki et al (2014) reported the measurement of 243 Cm, 244 Cm, 245 Cm, 246 Cm and 240 Pu using a Thermo Finigan Element 2 for nuclear forensics applications. 310 Gourgiotis et al (2010) used ICP-QMS (Thermo Electron X-series) for Cm and Cf isotope measurement in transmutation studies. 311 Sample introduction was via a quartz Peltier-cooled impact bead spray chamber (natural aspiration) and micro concentric nebulizer.…”

Atomic spectrometry update. Review of advances in the analysis of metals, chemicals and functional materials

“…A different method of chronometric determinations was developed by Kurosaki et al 149 who quantied Am, Cm and Pu using a sector eld ICP-MS instrument. In particular, the isotope ratio of 240 Pu and 244 Cm was determined.…”