New certified material and half-life measurement for Americium isotope

The JRC and the Commissariat à l’énergie atomique et aux énergies alternatives (CEA) have collaborated in the production of the first certified americium isotope (²⁴³Am) reference material for the quantification of americium by isotope dilution mass spectrometry (IDMS).

The material was produced in response to an urgent need in the fields of nuclear safeguards and security, nuclear forensics, and accountability in the nuclear fuel cycle. It contains a mixture of ²⁴¹Am (12%) and ²⁴³Am (88%) and has been characterised for the amount content of americium by IDMS, using an ²⁴¹Am spike produced from highly enriched ²⁴¹Pu material, and for the n(²⁴¹Am)/n(²⁴³Am) isotope amount ratios by thermal ionisation mass spectrometry (TIMS). In addition, absolute ²⁴³Am + ²⁴¹Am and relative ²⁴³Am/²⁴¹Am radioactivity measurements were performed as a redundancy check of the certified values.

By combining the unique JRC facilities at Geel site for standardisation of radioactivity with mass spectrometry, the JRC was also able to present a new value for the ²⁴³Am half-life. It has been precisely measured by an absolute and a relative method, i.e. by determining the specific activity of ²⁴³Am and the specific activity ratio with ²⁴¹Am. Accurate values for the decay constant or half-life of trans-uranium nuclides are required for accounting of nuclear material, assay of targets used in nuclear physics experiments, and characterisation of isotopic mixtures for radioanalytical purposes.

Moreover, this project provided a unique opportunity for the mass spectrometry community to assess the current state of practice for americium measurements. To this end, an ²⁴³Am inter-laboratory comparison (ILC) was organised in parallel to the certification campaign by CETAMA, using the same material.

Additional information can be found on the articles 243Am certified reference material for mass spectrometry and Absolute and relative measurement of the 243Am half-life on springer.com

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