Neutrino mass and low-temperature calorimetry

We describe how the problem of measuring the neutrino mass led us to the development of low-temperature calorimetry. The search for a “17-keV neutrino” concluded with a negative result, but a wide range of applications are now carried on by us and other groups in the fields of x-ray astronomy, recoil measurements of dark matter particles, high precision particle spectrometry, specific heat determinations, neutron detection, and rare decay studies. The masses of the bolometers (calorimeters) extend from 1 mg to 1 kg, nearly as large as for quantum detectors. By lowering the temperature into the 10- 20-mK range, calorimetry is on its way to substantially surpassing the high precision of particle metrology obtainable with the quantum detectors. Calorimeter developments and perspectives are discussed.