Nuclear physics for fundamental data

The data characterizing the decay of radionuclides are used in various fields of study or application:
– in ionizing radiation metrology, for calibration of detectors or for response simulations of certain instruments for example,
– in nuclear fuel cycle management, for the calculation of residual heat in reactors, waste storage or radiation protection of workers,
– in nuclear physics, for nuclear structure studies and validation of theoretical models,
– for predictive purposes for diagnostic or therapeutic uses (nuclear medicine and radiotherapy).

Evaluation of nuclear data

User demand for reliable and recommended data has existed for years. Part of the study aims to make up for the lack of knowledge of certain parameters of decay schemes, to make and/or call on the international community to take new measurements and, using the new results, to reconstruct new schemes and make them available to users.
Thus, the LNHB is engaged in a long-term project to evaluate nuclear and atomic data and make available recommended values for radionuclide decay schemes. For this purpose, a group of specially trained evaluators collect and analyse all the experimental or calculated values published at international level. This work is carried out in the framework of an international collaboration set up in 1995, the Decay Data Evaluation Project (DDEP) and the data table resulting from these evaluations is published by the LNHB.

Study of beta spectra

This study consists of carrying out a beta-spectrum shape calculation program for any type of transition, which is validated experimentally.
This work involves performing theoretical calculations and experimental validation using beta spectrometers developed in the laboratory: a device equipped with a semiconductor detector, and a magnetic metallic calorimeter.
Initial results show that deconvolution of the measured spectrum with the detection system’s response allows the real shape of the beta spectrum to be obtained with great precision.
Another important achievement of this study was the availability of the BetaShape program to improve nuclear data on beta emissions.

– MetroBETA (Metrology-based improvements to radionuclide beta spectra)
Decay Data Evaluation Project

Institut Pluridisciplinaire Hubert Curien (CNRS-Université de Strasbourg)

– M.A. Kellett, M.-M. Bé, 148Pm: Evaluation of the decay schemes for two important reactor poisons, (2014), Applied Radiation Isotopes 87 95
DOI: 10.1016/j.apradiso.2013.11.009
– M.A. Kellett, 177Lu: DDEP Evaluation of the decay scheme for an emerging radiopharmaceutical, Applied Radiation and Isotopes, (2016) Appl Radiat Isot., 109:129-32.
DOI: 10.1016/j.apradiso.2015.11.057
– M. Loidl, C. Le-Bret, M. Rodrigues and X. Mougeot, Evidence for the exchange effect down to very low energy in the beta decays of 63Ni and 241Pu, (2014) Journal of Low Temperature Physics 176, 1040-1045
DOI: 10.1007/s10909-014-1190-9
– X. Mougeot, C. Bisch, Consistent calculation of the screening and exchange effects in allowed ß- transitions, (2014), Physical Review A 90 012501.
DOI: 10.1103/PhysRevA.90.012501