ECHo Collaboration and ECHo-Mainz Team

The determination of the absolute scale of the neutrino masses is one of the most challenging questions in particle physics. The discovery that neutrinos do in fact have a finite mass was honored by the Nobel Prize in Physics in 2015, awarded to the discoverers of neutrino oscillations, Takaaki Kajita and Arthur B. McDonald. Yet, the magnitude of this mass is still unknown. Different approaches are followed to achieve a sensitivity on neutrino masses in the sub-eV range. Among them, experiments exploring the beta decay and electron capture processes of suitable nuclides can provide necessary information on the electron neutrino mass value. The Electron Capture 163Holmium experiment ECHo aims to investigate the electron neutrino mass in the sub-eV range by means of the analysis of the calorimetrically measured energy spectrum following the electron capture process of 163Ho. A high precision and high statistics spectrum will be measured by means of low temperature magnetic calorimeter arrays.
Within the ECHo collaboration, the ECHo-Mainz team is responsible for providing radiochemically pure samples of 163Ho for the different task groups within the collaboration. This includes samples embedded in magnetic microcalorimeters produced and operated by the ECHo-Heidelberg team at the Kirchhoff Institute for Physics as well as samples suitable for Penning trap mass spectrometry, which is carried out by the team led by the Max Planck Institut für Kernphysik Heidelberg.
ECHo-Mainz evaluates different production pathways for 163Ho, produces sufficient amounts of the radioisotope, provides efficient high-quality separation by chemical as well as physical means, and characterizes the obtained samples, in close connection with the ECHo-Tübingen team.