Status of the MARE Experiment

The neutrino mass experiment MARE is presently focusing on the feasibility study of electron capture decaying isotope
¹⁶³
Ho, as an alternative approach to the well investigated
¹⁸⁷
Re beta decaying isotope.
¹⁶³
Ho, which undergoes a very low
Q
value decay with about 4500 years half life, gives the advantages of using very low mass metallic absorber transition edge sensor microcalorimeters and self energy calibrating spectral measurements. These features match very well with the basic technique of transition edge sensor microcalorimeter arrays that have in fact reached a maturity that allows envisaging a full-scale experiment. The preliminary results of radioactive
¹⁶³
Ho doped absorbers are presented and discussed in the framework of the MARE goal of achieving a sensitivity of 0.1-0.2 eV/c
²
for the neutrino Mass.