Superconducting absorber for 163Ho electron capture decay measurement

163Ho Electron Capture (EC) decay has been studied since the last decade for measuring the neutrino mass. These studies have shown that the experimental energies of the EC decay lines are slightly different from the ones expected from theory. A true calorimetric measurement should be able to fix definitively the level energies. In 1996 (Phys. Lett. B 398 (1996) 415), the first calorimetric measurement of this spectrum was obtained by the Genoa group, which was able to resolve the doublet MI–MII and NI–NII at about 1800 and 400 eV, respectively. The major drawback of this detector was the absorber, which had not been homogeneously made because the radioactive source was in dielectric form surrounded by the superconducting absorber. Here we present a new absorber for 163Ho experiment, which will be used in a new calorimetric measurement. It consists of a superconducting compound of yttrium, Y3Rh4Sn13, in which 163Ho is homogeneously spread.