Production of high purity TeO2 single crystals for the study of neutrinoless double beta decay

High purity TeO2 crystals are produced to be used for the search for the neutrinoless double beta decay of 130Te. Dedicated production lines for raw material synthesis, crystal growth and surface processing were built compliant with radio-purity constraints specific to rare event physics experiments. High sensitivity measurements of radio-isotope concentrations in raw materials, reactants, consumables, ancillaries and intermediary products used for TeO2 crystals production are reported. Production and certification protocols are presented and resulting ready-to-use TeO2 crystals are described

Initial performance of the CUORE-0 experiment

CUORE-0 is a cryogenic detector that uses an array of tellurium dioxide bolometers to search for neutrinoless double-beta decay of 130Te . We present the first data analysis with 7.1kg·y of total TeO2 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 ) and in the α background-dominated region (2.70 to 3.90MeV ) have been measured to be 0.071±0.011 and 0.019±0.002counts/(keV·kg·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 . 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

Searching for Neutrinoless Double-Beta Decay of 130Te with CUORE

Neutrinoless double-beta (0 <math id="M1" xmlns="http://www.w3.org/1998/Math/MathML"><mi>ν</mi><mi>β</mi><mi>β</mi></math> ) decay is a hypothesized lepton-number-violating process that offers the only known means of asserting the possible Majorana nature of neutrino mass. The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for 0 <math id="M2" xmlns="http://www.w3.org/1998/Math/MathML"><mi>ν</mi><mi>β</mi><mi>β</mi></math> decay of 130Te using an array of 988 TeO2 crystal bolometers operated at 10 mK. The detector will contain 206 kg of 130Te and have an average energy resolution of 5 keV; the projected 0 <math id="M3" xmlns="http://www.w3.org/1998/Math/MathML"><mi>ν</mi><mi>β</mi><mi>β</mi></math> decay half-life sensitivity after five years of livetime is 1.6 × 1026 y at 1 <math id="M4" xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>σ</mi></mrow></math> (9.5 × 1025 y at the 90% confidence level), which corresponds to an upper limit on the effective Majorana mass in the range 40–100 meV (50–130 meV). In this paper, we review the experimental techniques used in CUORE as well as its current status and anticipated physics reach

Exploring the neutrinoless double beta decay in the inverted neutrino hierarchy with bolometric detectors

Neutrinoless double beta decay ( 0νββ ) is one of the most sensitive probes for physics beyond the Standard Model, providing unique information on the nature of neutrinos. In this paper we review the status and outlook for bolometric 0νββ  decay searches. We summarize recent advances in background suppression demonstrated using bolometers with simultaneous readout of heat and light signals. We simulate several configurations of a future CUORE-like bolometer array which would utilize these improvements and present the sensitivity reach of a hypothetical next-generation bolometric 0νββ  experiment. We demonstrate that a bolometric experiment with the isotope mass of about 1 ton is capable of reaching the sensitivity to the effective Majorana neutrino mass ( |mee| ) of order 10–20 meV, thus completely exploring the so-called inverted neutrino mass hierarchy region. We highlight the main challenges and identify priorities for an R&D program addressing them