A Search for Neutrinoless Double-Beta Decay in Tellurium-130 with CUOR

The Cryogenic Underground Observatory for Rare Events (CUORE) is a ton-scale cryogenic experiment designed to search for neutrinoless double-beta (0 vbetabeta) decay in 130Te. The experiment consists of 988 ultracold TeO2 bolometric crystals, which act as both the 0vbetabeta decay sources and detectors, in a close-packed configuration. This dissertation presents a search for 0vbetabeta decay with the first two months of CUORE data An observation of 0 vbetabeta decay would be direct evidence of lepton number violation and unambiguously prove that, neutrinos are Majorana particles.;We analyze the first 83.6 kg·yr of TeO2 exposure and find no evidence for 0vbetabeta decay. We set a limit of T0v1/2 > 1.5 x 1025 yr (90% C.L.) by combining this exposure with that from two predecessor experiments, CUORE-0 and Cuoricino. With this data, we set the world-leading limit on the rate of 0vbetabeta decay in 130Te. The CLORE bolometer array is characterized by an effective energy resolution of (7.7 +/- 0.5) keV FWHM and background of (0.011 +/- 0.002) counts; (keV·kg·yr) at the 0 vbetabeta decay Q-value. This is the lowest background level achieved to date in such a large-scale cryogenic experiment. meeting our expectations and requirements for this search.;A good understanding of the detector energy scale through regular calibration is crucial for observation of 0vbetabeta decay and other rare processes. The 988 bolometers of the CUORE detector are calibrated with low-activity 232Th sources, which are cooled and routed to their positions inside the cryostat at monthly intervals. This disscrt ation also discusses the design and implementation of this calibration system.