Speaker
Description
Radionuclide monitoring involves measurements of the concentrations of radioactive particles and noble gases in air, soil, and liquid samples. After collection and appropriate treatment of the samples, γ and β emissions are measured by means of Ge detectors and β counters, respectively. Quantification of such spectra relies heavily on up-to-date evaluations of the nuclear structure and decay data of all potential candidate radionuclides. R&D work and Monte-Carlo simulations for identification and quantification of radionuclides also depend on a sound knowledge of the intensities of the γ and β-, ec/β+ emissions, along with their equivalent atomic radiations.
We report on an international project coordinated by the International Atomic Energy Agency [1] to improve and update the decay data for 27 selected long-lived fission products considered to be of high priority for worldwide radionuclide monitoring efforts. Half-lives, and emission energies and intensities of the selected radionuclides have been evaluated and recommended on the basis of a common set of guidelines to produce an adopted decay data set. Both β- and ec/β+ properties were calculated by means of the BetaShape code [2,3], while atomic radiation data have been determined from the BrIccEmis code [4]. A final set of recommended data files have been produced in ENSDF format and will be published and made available to laboratories and international bodies such as the Comprehensive Test-Ban Treaty Organisation (CTBTO) involved in the monitoring of such radionuclides.
[1] Jun Chen, F. Kondev, P. Dimitriou, Improved Decay Data for Monitoring Applications, Summary report of the IAEA Technical Meeting, 24-26 March 2021, IAEA report INDC(NDS)-0828, July 2021.
[2] X. Mougeot, Reliability of Usual Assumptions in the Calculation of β and ν Spectra, Phys. Rev. C91 (2015) 055504, 1-12; DOI: https://doi.org/10.1103/PhysRevC.91.055504
Erratum, Phys. Rev. C92 (2015) 059902, 1; DOI:https://doi.org/10.1103/PhysRevC.92.059902
[3] X. Mougeot, Towards High-precision Calculation of Electron Capture Decays, Appl. Radiat. Isot. 154 (2019) 108884, 1-8; DOI: https://doi.org/10.1016/j.apradiso.2019.108884
[4] B.P.E. Tee, T. Kibédi, B.Q. Lee, M. Vos, R. du Rietz, A.E. Stuchbery, Development of a New Database for Auger-electron and X-ray Spectra, Proc. Heavy Ion Accelerator Symposium (HIAS2019), 9-13 September 2019, Canberra, Australia, editors: A.J. Mitchell, S. Pavetich, D. Koll, EPJ Web Conf. 232 (2020) 01006, 1-4; DOI: https://doi.org/10.1051/epjconf/202023201006