UC Berkeley

CUORE-0 is a cryogenic detector that uses an array of tellurium dioxide bolometers to search for neutrinoless double-beta decay of 130Te$$\mathrm {^{130}Te}$$. We present the first data analysis with 7.1kg·y$$7.1 \,\mathrm {kg\cdot y}$$ of total TeO2$$\mathrm {TeO_2}$$ exposure focusing on background measurements and energy resolution. The background rates in the neutrinoless double-beta decay region of interest (2.47 to 2.57MeV$$2.57 \,\mathrm {MeV}$$) and in the α$$\alpha $$ background-dominated region (2.70 to 3.90MeV$$3.90\,\mathrm {MeV}$$) have been measured to be 0.071±0.011$${0.071\pm 0.011}$$ and 0.019±0.002counts/(keV·kg·y)$${0.019\pm 0.002}\,\mathrm {counts/(keV\cdot kg\cdot y)}$$, respectively. The latter result represents a factor of 6 improvement from a predecessor experiment, Cuoricino. The results verify our understanding of the background sources in CUORE-0, which is the basis of extrapolations to the full CUORE detector. The obtained energy resolution (full width at half maximum) in the region of interest is 5.7keV$$5.7\,\mathrm {keV}$$. Based on the measured background rate and energy resolution in the region of interest, CUORE-0 half-life sensitivity is expected to surpass the observed lower bound of Cuoricino with one year of live time.