High-resolution bolometers for rare events detection

Since many years the Milano–Gran Sasso collaboration is developing large mass calorimeters for Double Beta Decay and Dark Matter searches, employing TeO2 crystals as absorber elements. Recently, we have focused our attention on the improvement of the detector resolution: an efficient dumping suspension and the implementation of a new cold electronics device, have strongly suppressed the main sources of noise. The increase in S/N ratio has been of almost an order of magnitude and the resolution achieved is competitive with that of Ge diodes for γ-rays detection, while a FWHM of 3.2±0.3keV has been obtained for 5.4MeV alpha particles, the best result with any kind of detector.