The CUORE experiment, a ton-scale cryogenic bolometer array, recently began operation at the Laboratori Nazionali del Gran Sasso in Italy. The array represents a significant advancement in this ...technology, and in this work we apply it for the first time to a high-sensitivity search for a lepton-number-violating process: ^{130}Te neutrinoless double-beta decay. Examining a total TeO_{2} exposure of 86.3 kg yr, characterized by an effective energy resolution of (7.7±0.5) keV FWHM and a background in the region of interest of (0.014±0.002) counts/(keV kg yr), we find no evidence for neutrinoless double-beta decay. Including systematic uncertainties, we place a lower limit on the decay half-life of T_{1/2}^{0ν}(^{130}Te)>1.3×10^{25} yr (90% C.L.); the median statistical sensitivity of this search is 7.0×10^{24} yr. Combining this result with those of two earlier experiments, Cuoricino and CUORE-0, we find T_{1/2}^{0ν}(^{130}Te)>1.5×10^{25} yr (90% C.L.), which is the most stringent limit to date on this decay. Interpreting this result as a limit on the effective Majorana neutrino mass, we find m_{ββ}<(110-520) meV, where the range reflects the nuclear matrix element estimates employed.
The past few decades have seen major developments in the design and operation of cryogenic particle detectors. This technology offers an extremely good energy resolution – comparable to semiconductor ...detectors – and a wide choice of target materials, making low temperature calorimetric detectors ideal for a variety of particle physics applications. Rare event searches have continued to require ever greater exposures, which has driven them to ever larger cryogenic detectors, with the CUORE experiment being the first to reach a tonne-scale, mK-cooled, experimental mass. CUORE, designed to search for neutrinoless double beta decay, has been operational since 2017 at a temperature of about 10 mK. This result has been attained by the use of an unprecedentedly large cryogenic infrastructure called the CUORE cryostat: conceived, designed and commissioned for this purpose.
In this article the main characteristics and features of the cryogenic facility developed for the CUORE experiment are highlighted. A brief introduction of the evolution of the field and of the past cryogenic facilities are given. The motivation behind the design and development of the CUORE cryogenic facility is detailed as are the steps taken toward realization, commissioning, and operation of the CUORE cryostat. The major challenges overcome by the collaboration and the solutions implemented throughout the building of the cryogenic facility will be discussed along with the potential improvements for future facilities.
The success of CUORE has opened the door to a new generation of large-scale cryogenic facilities in numerous fields of science. Broader implications of the incredible feat achieved by the CUORE collaboration on the future cryogenic facilities in various fields ranging from neutrino and dark matter experiments to quantum computing will be examined.
In this article we describe the background challenges for the CUORE experiment posed by surface contamination of inert detector materials such as copper, and present three techniques explored to ...mitigate these backgrounds. Using data from a dedicated test apparatus constructed to validate and compare these techniques we demonstrate that copper surface contamination levels better than 10−7- 10−8 Bq/cm2 are achieved for 238U and 232Th. If these levels are reproduced in the final CUORE apparatus the projected 90% C.L. upper limit on the number of background counts in the region of interest is 0.02–0.03 counts/keV/kg/y depending on the adopted mitigation technique.
► Measurement of radioactive contaminations of TeO2 crystals for the CUORE experiment. ► Both bulk and surface contamination from 238U and 232Th decay chains is not found. ► The upper limits are ...calculated to be within the contract specification. ► An extrapolation to CUORE background from bulk and surface contamination is performed.
The CUORE Crystal Validation Runs (CCVRs) have been carried out since the end of 2008 at the Gran Sasso National Laboratories, in order to test the performance and the radiopurity of the TeO2 crystals produced at SICCAS (Shanghai Institute of Ceramics, Chinese Academy of Sciences) for the CUORE experiment. In this work the results of the first 5 validation runs are presented. Results have been obtained for bulk contaminations and surface contaminations from several nuclides. An extrapolation to the CUORE background has been performed.
The past few decades have seen major developments in the design and operation of cryogenic particle detectors. This technology offers an extremely good energy resolution – comparable to semiconductor ...detectors – and a wide choice of target materials, making low temperature calorimetric detectors ideal for a variety of particle physics applications. Rare event searches have continued to require ever greater exposures, which has driven them to ever larger cryogenic detectors, with the CUORE experiment being the first to reach a tonne-scale, mK-cooled, experimental mass. CUORE, designed to search for neutrinoless double beta decay, has been operational since 2017 at a temperature of about 10 mK. This result has been attained by the use of an unprecedentedly large cryogenic infrastructure called the CUORE cryostat: conceived, designed and commissioned for this purpose. In this article the main characteristics and features of the cryogenic facility developed for the CUORE experiment are highlighted. In this work, a brief introduction of the evolution of the field and of the past cryogenic facilities are given. The motivation behind the design and development of the CUORE cryogenic facility is detailed as are the steps taken toward realization, commissioning, and operation of the CUORE cryostat. The major challenges overcome by the collaboration and the solutions implemented throughout the building of the cryogenic facility will be discussed along with the potential improvements for future facilities. The success of CUORE has opened the door to a new generation of large-scale cryogenic facilities in numerous fields of science. Broader implications of the incredible feat achieved by the CUORE collaboration on the future cryogenic facilities in various fields ranging from neutrino and dark matter experiments to quantum computing will be examined.
The past few decades have seen major developments in the design and operation of cryogenic particle detectors. This technology offers an extremely good energy resolution – comparable to semiconductor ...detectors – and a wide choice of target materials, making low temperature calorimetric detectors ideal for a variety of particle physics applications. Rare event searches have continued to require ever greater exposures, which has driven them to ever larger cryogenic detectors, with the CUORE experiment being the first to reach a tonne-scale, mK-cooled, experimental mass. CUORE, designed to search for neutrinoless double beta decay, has been operational since 2017 at a temperature of about 10 mK. This result has been attained by the use of an unprecedentedly large cryogenic infrastructure called the CUORE cryostat: conceived, designed and commissioned for this purpose. In this article the main characteristics and features of the cryogenic facility developed for the CUORE experiment are highlighted. In this work, a brief introduction of the evolution of the field and of the past cryogenic facilities are given. The motivation behind the design and development of the CUORE cryogenic facility is detailed as are the steps taken toward realization, commissioning, and operation of the CUORE cryostat. The major challenges overcome by the collaboration and the solutions implemented throughout the building of the cryogenic facility will be discussed along with the potential improvements for future facilities. The success of CUORE has opened the door to a new generation of large-scale cryogenic facilities in numerous fields of science. Broader implications of the incredible feat achieved by the CUORE collaboration on the future cryogenic facilities in various fields ranging from neutrino and dark matter experiments to quantum computing will be examined.
The CUORE experiment, a ton-scale cryogenic bolometer array, recently began operation at the Laboratori Nazionali del Gran Sasso in Italy. The array represents a significant advancement in this ...technology, and in this work we apply it for the first time to a high-sensitivity search for a lepton-number-violating process: 130Te neutrinoless double-beta decay. Examining a total TeO2 exposure of 86.3 kg yr, characterized by an effective energy resolution of (7.7 ± 0.5) keV FWHM and a background in the region of interest of (0.014 ± 0.002) counts /(keV kg yr), we find no evidence for neutrinoless double-beta decay. Including systematic uncertainties, we place a lower limit on the decay half-life of T $0ν\atop{1/2}$ (130 Te) > 1.3 × 1025 yr (90% C.L.); the median statistical sensitivity of this search is 7.0 × 1024 yr. In conclusion, combining this result with those of two earlier experiments, Cuoricino and CUORE-0, we find T $0ν\atop{1/2}$ (130Te) > 1.5 × 1025 yr (90% C.L.), which is the most stringent limit to date on this decay. Interpreting this result as a limit on the effective Majorana neutrino mass, we find mββ < (110 - 520) meV , where the range reflects the nuclear matrix element estimates employed.
The formulae for
m
-order correlators
K
m
of a given particle observable (e.g., energy, transverse momentum or a conserved discrete quantum number) accounting for the track reconstruction ...efficiencies in a real detector are presented. The calculation of second- to fourth-order correlators is considered in some detail. Similar to the case of an ideal detector, the correlators can be expressed through the event-by-event fluctuation measures of the observable single event mean, the pseudocorrelators (determined by the pseudo-central moments of the observable distribution) and their cross terms. It allows one to avoid the combinatorics and essentially reduce the computer time when calculating the higher-order correlators in high multiplicity events. Compared with the case of ideal detector, this reduction is somewhat smaller due to the increased number of pseudocorrelators and additional calculations of the moments of the distribution of the track weights. For a constant track reconstruction efficiency, the correlator formulae reduce to those for an ideal detector. However, in real experiments the efficiencies are usually essentially dependent on particle momenta and may lead to substantial corrections of momentum correlators on the level of tens of percent.
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