A study about the alpha-particle emission probabilities and energies in the decay of 240Pu has been done at IRMM in 2003. Some discrepancies were found between the published data. Results of measurements done at IRMM revealed also a discrepancy with some published data. (Sibbens et al., 2003. Study of alpha-particle emission probabilities and energies in the decay of 240Pu. ICRM2003, Applied Radiation and Isotopes, in press.) Only a few direct measurements by alpha-particle spectrometry could be found in the literature. With the new available detectors and analysis programs, the project will result in a new set of alpha-particle emission probabilities and energies in the decay of 240Pu. The output will contribute to obtain data with significantly lower uncertainties and better information concerning the less intense peaks.
Final Report 2010-10-18
The project has been completed and the report can be downloaded here>>.
The project was successfully completed.
Alpha-particle emission probabilities of six alpha transitions of 240Pu have been determined.Enriched 240Pu material was measured by alpha-particle spectrometry and γ-ray spectrometry and the resulting spectra analysed by the participating laboratories. The major uncertainty component for the Pα values determined by alpha-particle spectrometry was due to the peak fit, for the Pα values determined by gamma-ray spectrometry was due to nuclear data input.
The Pα values of the main alpha transitions show agreement with those measured in the past by alpha-particle spectrometry. Two small alpha-particle branches, α310 and α688, were measured for the first time with silicon detectors.
The emission probability for the α688 transition was found to be higher than the currently recommended value by DDEP. The α522 transition could not be observed by alpha-particle spectrometry, yielding an upper limit for its emission probability which is lower than the currently recommended value by DDEP. The corresponding gamma-ray emission probability of 240Pu was found to be more than an order of magnitude lower than the value reported in the literature.
The α-particle emission energies were not scrutinised in this work, leaving the issue open for future research.
The main results are presented at the ICRM 2009 conference in Bratislava and published in the paper:
G. Sibbens, S. Pommé, T. Altzitzoglou, E. García-Toraño, H. Janssen, R. Dersch, O. Ott, A.Martín Sánchez, M.P. Rubio Montero, M. Loidl, N. Coron, P. De Marcillac, T.M. Semkow, Alphaparticle emission probabilities in the decay of 240Pu, Applied Radiation and Isotopes 68 (2010) 1459-1466