The aim of this work package is to improve the theoretical calculations of energy spectra from beta emission in order to specifically calculate each beta transition regardless of its nature. A computer code will be developed to include as accurately as possible nuclear structure effects. The evaluation of the nuclear matrix elements will have to be performed in the code that will be developed, which will allow absolute beta transition probabilities to be calculated, as well as partial half-lives and log ft values.
The aim of this work package is to provide significant technical improvements to metallic magnetic calorimeter (MMC) based beta spectrometry for radionuclide metrology. At present, the MMC-based system at CEA is the only such system worldwide for radionuclide metrology. Within this workpackage an MMC-based beta spectrometer will be developer at PTB.
The activities within this work package have the ambitious goal formulated in deliverable D6 to produce spectra of pure beta emitters Sm-151, C-14, Tc-99 and Cl-36 with the highest energy resolution currently possible and minimised spectrum distortions. These spectra will be used for comparison with calculated beta spectra and spectra of the same radionuclides measured with conventional Si(Li) detectors and other proposed techniques.
The aim of this work package is to provide alternative experimental techniques for the measurement of the beta spectrum shape. These methods will be complementary to the MMC technique and will also provide improvements for the measurement at higher energy, up to a few MeV. This will provide additional data to compare with the theoretical calculations of beta spectra.
In this work package, we propose three experiments based on different techniques. This will provide a set of data which will allow independent comparisons and good reliability of the measurements. All the methods have already shown their ability to accurately measure beta spectra and the aim of each task will be to improve data quality, to measure additional radionuclides and reduce uncertainties, thereby providing an unprecedented data set for comparison with theoretical calculations.
The aim of this work package is to improve the measurement of the becquerel unit for pure beta emitters. Activity measurements for these radionuclides are generally carried out using the Liquid Scintillation Counting (LSC) technique. The analysis on activity determination of Ni-63 samples shows that accurate beta spectra lead to significantly better final uncertainties for LSC activity determinations. As activity is the variation of the number of radioactive nuclei per unit of time, this quantity is directly linked to the absolute transition probability, which can be calculated from the beta spectrum.
The aim of this work package is to ensure the work carried out in this project is correctly communicated to the relevant user communities and the knowledge gained during the development of both calculation tools and measurement methods is available to interested parties.