209Bi level calculation

209Bi has recentely observed to α-decay with scintillating bolometer, to the ground state (GS) and to first the excited state (ES). although of the belief it was a stable nuclei. Even previous measurement observed the decay, but only the GS-GS transition. This decay belongs to a special class of decays occurring in odd-A nuclei with an extra nucleon outside a closed shell. 209Bi alpha decay branching ratios (BR) to the ground and to two different excited states were numerically evaluated. While the BR for the ground-state decay is well known, the calculation for the excited states was performed for the first time. Even if the used model is a simplified theory (not strictly correct for deformed nuclei), it gives a good estimate of the decay half life

Performance analysis of the European X-ray Free Electron Laser 3.9 GHz superconducting cavities

The limits of performance of the European XFEL 3.9 GHz superconducting cavities were investigated. Most cavities exhibited high field Q slope, reaching the breakdown field at approximately $22\text{ }\text{ }\mathrm{MV}/\mathrm{m}$. We hypothesize that this limit is a feature of high frequency cavities and can be explained by a thermal model incorporating field dependent surface resistance. The results obtained from simulations were in good agreement with experimental data obtained at 2 K

Double-beta decay of 130^{130}Te to the first 0+^{+} excited state of 130^{130}Xe with CUORICINO

The CUORICINO experiment was an array of 62 TeO$_{2}$ single-crystal bolometers with a total $^{130}$Te mass of $11.3\,$kg. The experiment finished in 2008 after more than 3 years of active operating time. Searches for both $0\nu$ and $2\nu$ double-beta decay to the first excited $0^{+}$ state in $^{130}$Xe were performed by studying different coincidence scenarios. The analysis was based on data representing a total exposure of N($^{130}$Te)$\cdot$t=$9.5\times10^{25}\,$y. No evidence for a signal was found. The resulting lower limits on the half lives are $T^{2\nu}_{1/2}(^{130} Te\rightarrow^{130} Xe^{*})>1.3\times10^{23}\,$y (90% C.L.), and $T^{0\nu}_{1/2}(^{130} Te\rightarrow^{130} Xe^{*})>9.4\times10^{23}\,$y (90% C.L.).Comment: 6 pages, 4 figure

The low radioactivity link of the CUORE experiment

CUORE will be an array of 988 TeO2 bolometers (5 × 5 × 5 cm3) held at about 10 mK. It will study the very rare double β decay process from 130Te. The electrical connections of the array to the room temperature electronics will consist in about 2000 wires. We will describe the design and characterization of the 3 interconnection sectors going from the detectors to the mixing chamber, the coldest stage at which the array is thermally and mechanically anchored, and from the mixing chamber to room temperature. The lower part consists of a set of 2.3 m long, 50 μm thick, Cu-insulator tapes having PEN (Polyethylene 2.6 Naphthalate) substrate, on which a pattern of copper tracks are etched. The differential layout pattern chosen allows obtaining a signal cross talk between adjacent channels of about 0.024%, together with a capacitance of about 26 pF/m and a resistance larger than 200 GΩ/m. On the top of the mixing chamber, Cu-Kapton boards are used to join the tapes to the second upward-going 2 m long links, implemented with twisted NbTi wires, interwoven in a NOMEX® texture. NbTi-NOMEX link features about 100 pF/m and negligible level of cross-talk. The radioactivity content of Cu-PEN tapes, Cu-Kapton boards, NbTi-NOMEX ribbons and connectors has been investigated and found to be compliant with the experimental requirements. A mechanical study has been done to quote the vibration transmission properties of the highly packaged tapes

CUORE and beyond: bolometric techniques to explore inverted neutrino mass hierarchy

The CUORE (Cryogenic Underground Observatory for Rare Events) experiment will search for neutrinoless double beta decay of $^{130}$Te. With 741 kg of TeO$_2$ crystals and an excellent energy resolution of 5 keV (0.2%) at the region of interest, CUORE will be one of the most competitive neutrinoless double beta decay experiments on the horizon. With five years of live time, CUORE projected neutrinoless double beta decay half-life sensitivity is $1.6\times 10^{26}$ y at $1\sigma$ ($9.5\times10^{25}$ 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). Further background rejection with auxiliary light detector can significantly improve the search sensitivity and competitiveness of bolometric detectors to fully explore the inverted neutrino mass hierarchy with $^{130}$Te and possibly other double beta decay candidate nuclei.Comment: Submitted to the Proceedings of TAUP 2013 Conferenc

Status of the CUORE and results from the CUORE-0 neutrinoless double beta decay experiments

CUORE is a 741 kg array of TeO2 bolometers for the search of neutrinoless double beta decay of 130Te. The detector is being constructed at the Laboratori Nazionali del Gran Sasso, Italy, where it will start taking data in 2015. If the target background of 0.01 counts/keV/kg/y will be reached, in five years of data taking CUORE will have a 1 sigma half life sensitivity of 10E26 y. CUORE-0 is a smaller experiment constructed to test and demonstrate the performances expected for CUORE. The detector is a single tower of 52 CUORE-like bolometers that started taking data in spring 2013. The status and perspectives of CUORE will be discussed, and the first CUORE-0 data will be presented.Comment: 7 pages, 4 figures, to be published in the proceedings of ICHEP 2014, 37th International Conference on High Energy Physics, Valencia (Spain) 2-9 July 201

Exploring the Neutrinoless Double Beta Decay in the Inverted Neutrino Hierarchy with Bolometric Detectors

Neutrinoless double beta decay (0nubb) 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 0nubb 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 0nubb 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.Comment: 22 pages, 15 figures, submitted to EPJ

First measurement of the partial widths of 209^{209}Bi decay to the ground and to the first excited states

$^{209}$Bi alpha decay to the ground and to the first excited state have been contemporary observed for the first time with a large BGO scintillating bolometer. The half-life of $^{209}$Bi is determined to be $\tau_{1/2}$=(2.01$\pm$0.08)$\cdot10^{19}$ years while the branching ratio for the ground-state to ground-state transition is (98.8$\pm$0.3)%.Comment: 5 pages, 4 figure

CUORE-0 results and prospects for the CUORE experiment

With 741 kg of TeO2 crystals and an excellent energy resolution of 5 keV (0.2%) at the region of interest, the CUORE (Cryogenic Underground Observatory for Rare Events) experiment aims at searching for neutrinoless double beta decay of 130Te with unprecedented sensitivity. Expected to start data taking in 2015, CUORE is currently in an advanced construction phase at LNGS. CUORE projected neutrinoless double beta decay half-life sensitivity is 1.6E26 y at 1 sigma (9.5E25 y at the 90% confidence level), in five years of live time, corresponding to an upper limit on the effective Majorana mass in the range 40-100 meV (50-130 meV). Further background rejection with auxiliary bolometric detectors could improve CUORE sensitivity and competitiveness of bolometric detectors towards a full analysis of the inverted neutrino mass hierarchy. CUORE-0 was built to test and demonstrate the performance of the upcoming CUORE experiment. It consists of a single CUORE tower (52 TeO2 bolometers of 750 g each, arranged in a 13 floor structure) constructed strictly following CUORE recipes both for materials and assembly procedures. An experiment its own, CUORE-0 is expected to reach a sensitivity to the neutrinoless double beta decay half-life of 130Te around 3E24 y in one year of live time. We present an update of the data, corresponding to an exposure of 18.1 kg y. An analysis of the background indicates that the CUORE performance goal is satisfied while the sensitivity goal is within reach.Comment: 10 pages, 3 figures, to appear in the proceedings of NEUTRINO 2014, 26th International Conference on Neutrino Physics and Astrophysics, 2-7 June 2014, held at Boston, Massachusetts, US

Validation of techniques to mitigate copper surface contamination in CUORE

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 10E-07 - 10E-08 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.Comment: 10 pages, 6 figures, 6 table