Tom Kieck, PhD student with Prof. Klaus Wendt in the ECHo Mainz team, is one winner of the poster competition at the Neutrino 2018 conference in Heidelberg. The poster topic is "Production, Separation and Implantation of 163Ho for Neutrino Mass Measurements". Conference website
Development of AMS at DREAMS for experimental determination of the ratio 163Ho/166mHo in ECHo samples. The long-lived 166mHo is an unwanted by-product of the 163Ho production, which is reduced to ultra-low levels (10-9) after sophisticated mass separation. For a background-free measurement of the 163Ho spectrum in the ECHo metallic magnetic calorimeters the absence of 166mHo is critical. DREAMS website
Samples prepared at Johannes Gutenberg University Mainz facilitate direct measurement of the mass difference of Ho-163 and Dy-163 to solve the Q-Value puzzle for the neutrino mass determination
Using samples of 163Ho that were prepared at the Institute for Nuclear Chemistry at the Johannes Gutenberg University Mainz, the atomic mass difference of 163Ho and 163Dy has been directly measured with the Penning-trap mass spectrometer SHIPTRAP at GSI Darmstadt by applying the novel phase-imaging ion-cyclotron-resonance technique. Our measurement has solved the long-standing problem of large discrepancies in the Q value of the electron capture in 163Ho determined by different techniques. Our measured mass difference shifts the current Q value of 2555(16) eV evaluated in the Atomic Mass Evaluation 2012 by more than 7σ to 2833 (30stat) (15sys) eV/c2. With the new mass difference it will be possible, e.g., to reach in the first phase of the ECHo experiment a statistical sensitivity to the neutrino mass below 10 eV, which will reduce its present upper limit by more than an order of magnitude. The results were published in Physical Review Letters on August 05, 2015 (S. Eliseev et al., Physical Review Letters 115, 062501 (2015)).
163Ho was produced by intense neutron irradiation of 162Er at the high-flux reactor at the Institute Laue Langevin at Grenoble, France and subsequently purified by using radiochemical separation techniques similar to those also used in research on the heaviest elements.