Work Package 4

High statistics measurement of the spectrum shape

The aim of this work package is to experimentally determine nuclear decay data and atomic fundamental
parameters (FP), and probabilities of higher order processes during the electron capture and the beta decay
with unprecedented precision. The measurements will focus on 55Fe and 129I. Precise FPs are essential for
precise activity standardisation using liquid scintillation counting. In addition, although secondary processes
during the decay have very weak probabilities and are generally ignored, when a level of 0.1 % uncertainty is
targeted, they can lead to non-negligible bias on activity determination.