Absolute and relative measurement of the 243Am half-life
M. Marouli, S. Pommé, Viktor Jobbágy, H. Stroh, R. Van Ammel, Adelheid Fankhauser, R. Jakopič, Stephan Richter, Yetunde Aregbe, Marielle Crozet, Christophe Maillard, Cédric Rivier, D. Roudil
Abstract
Abstract The half-life of 243 Am has been measured by an absolute and a relative method, i.e. by determining the specific activity of 243 Am and the specific activity ratio with 241 Am. A mixed 241,243 Am reference material was produced and certified for its americium mass content and its isotope amount ratios. The characterisation of the mass content of 243 Am was established by isotope dilution mass spectrometry using an 241 Am spike, produced from highly enriched 241 Pu material. The isotope amount ratios n ( 241 Am)/ n ( 243 Am) and n ( 242m Am)/ n ( 243 Am) were measured by thermal ionisation mass spectrometry. Activity measurements were performed by alpha-particle counting at a defined solid angle, as well as high-resolution alpha-particle spectrometry. From the 243 Am/ 241 Am activity and isotopic amount ratios, a value of 16.988 (24) was derived for the 243 Am/ 241 Am half-life ratio. Using a value of 432.6 (6) a for the 241 Am half-life, the corresponding 243 Am half-life value, 7349 (15) a, is in good agreement with the result obtained from the absolute method, 7342 (14) a. The mean value, 7345 (14) a, agrees well with data from literature and lowers the relative standard uncertainty to 0.2%.