The commissioning of the CUORE experiment: the mini-tower run

CUORE is a ton-scale experiment approaching the data taking phase in Gran Sasso National Laboratory. Its primary goal is to search for the neutrinoless double-beta decay in 130Te using 988 crystals of tellurim dioxide. The crystals are operated as bolometers at about 10 mK taking advantage of one of the largest dilution cryostat ever built. Concluded in March 2016, the cryostat commissioning consisted in a sequence of cool down runs each one integrating new parts of the apparatus. The last run was performed with the fully configured cryostat and the thermal load at 4 K reached the impressive mass of about 14 tons. During that run the base temperature of 6.3 mK was reached and maintained for more than 70 days. An array of 8 crystals, called mini-tower, was used to check bolometers operation, readout electronics and DAQ. Results will be presented in terms of cooling power, electronic noise, energy resolution and preliminary background measurements

Results from the Cuore Experiment

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers, each of them made of 52 crystals. The construction of the experiment was completed in August 2016 and the data taking started in spring 2017 after a period of commissioning and tests. In this work we present the neutrinoless double beta decay results of CUORE from examining a total TeO2 exposure of 86.3kg yr, characterized by an effective energy resolution of 7.7 keV FWHM and a background in the region of interest of 0.014 counts/ (keV kg yr). In this physics run, CUORE placed a lower limit on the decay half- life of neutrinoless double beta decay of 130Te > 1.3.1025 yr (90% C. L.). Moreover, an analysis of the background of the experiment is presented as well as the measurement of the 130Te 2vo3p decay with a resulting half- life of T2 2. [7.9 :- 0.1 (stat.) :- 0.2 (syst.)] x 10(20) yr which is the most precise measurement of the half- life and compatible with previous results

On boundary element - transfer matrix analysis of layered systems

The chain pattern of certain elastic systems such as layered softs lends itself to be exploited in ad hoc solution procedures. A method of this kind proposed earlier (1977, 1984) combines the boundary integral approach (in its discretised, boundary element version) and the transfer matrix concept and exhibits a special appeal as for simplicity, elegance and compactness of the final reduced equation system. In this paper we analyse such BE-TM technique using mechanical interpretations and some notions of numerical analysis (primarily on matrix conditioning). The findings are as follows: outside of a relatively narrow range of geometry ratios (layer thickness over a typical discretization length) certain submatrices to invert are bound to become ill-conditioned, causing significant inaccuracies in the resulting tractions; this intrinsic limitation of applicability strongly depends on the adopted computation precision. Alternative methods, which avoid such limitation but still exploit the chain pattern, are envisaged and developed in a parallel paper

Boundary element formulation for geometrically nonlinear elastostatics

The basic integral relationships for geometrically nonlinear problems are presented. Using the boundary element method they allow for the solution of a new range of problems in geometrically nonlinear elastostatics

On calibration of orthotropic elastic-plastic constitutive models for paper foils by biaxial tests and inverse analyses

In this paper two procedures are developed for the identification of the parameters contained in an orthotropic elastic-plastic-hardening model for free standing foils, particularly of paper and paperboard. The experimental data considered are provided by cruciform tests and digital image correlation. A simplified version of the constitutive model proposed by Xia et al. (Int J. Solids Struct 39:4053–4071, 2002) is adopted. The inverse analysis is comparatively performed by the following alternative computational methodologies: (a)<mathematical programming by a trust-region algorithm; (b)<proper orthogonal decomposition and artificial neural network. The second procedure rests on preparatory once-for-all computations and turns out to be applicable economically and routinely in industrial environments