Figure 6: Background spectra from CUORE-0 (shaded, red) and Cuoricino (black) in the energy region dominated by degraded particles [24]. The sixfold reduction in background achieved by CUORE-0 in the energy ranges 2.7–3.1 MeV and 3.4–3.9 MeV is clearly evident. The prominent peak at 3.3 MeV is from decay of 190Pt, which is present in the TeO2 crystals from their growth. The non-Gaussian shape of the peak is due to the fact that these spectra are made by summing the contributions from many detector channels having different (Gaussian) energy resolutions and positions, the variations in the latter arising because of calibration uncertainties.