Prototype thermal detectors for a 187Re neutrino mass experiment

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