Work Packages WP1 – Advanced MMC-spectrometers for decay-scheme independent radionuclide metrlogy WP2 – Radioactive source preparation compatible with novel cryogenic detectors for absolute activity determination, comparison with established activity standardisation techniques and high-resolutionspectrometry of selected radionuclides WP3 – Radioactive source absolute activity determination by means of low temperature calorimeters and its comparison to established activity standardisation techniques and high-resolution spectrometry of selected radionuclides WP4 – High statistics measurement of the spectrum shape WP5 – High-precision theoretical calculations of beta spectrum shapes and electron-capture decays