PROTOTYPE THERMAL DETECTORS FOR A RE-187 NEUTRINO MASS EXPERIMENT

We report on a new method to measure the electron antineutrino mass, c onsisting of the end-point study of Re-187 beta-spectrum (Q-value=2.6 keV) collected calorimetrically (source=detector approach) with high e nergy resolution and statistics. The proposed detector is a micro-bolo meter, single or in an array structure, containing a total rhenium mas s of similar to 1 mg, operated at a temperature of a few tens of mK an d able to reach 10 eV energy resolution. As phonon sensors, we are dev eloping silicon thermistors doped by implantation; some tests are perf ormed also with neutron transmutation doped germanium thermistors. We have obtained up to now promising energy resolutions down to similar t o 11 eV with tin absorbers (as test devices) and similar to 70 eV with rhenium absorbers.