TeO2 bolometers to search for Double Beta Decay of130Te: status of art |
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Authors: | A. Alessandrello C. Brofferio D. V. Camin O. Cremonesi E. Fiorini E. Garcia A. Giuliani P. de Marcillac M. Pavan G. Pessina E. Previtali L. Zanotti |
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Affiliation: | (1) Dipartimento di Fiscia dell'Universita' e INFN, Via Celoria 16, 20133 Milano, Italy;(2) CEE fellowship at Lab. Naz. del Gran Sasso, INFN, 67010 Assergi, L'Aquila, Italy |
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Abstract: | A 334g TeO2 crystal is operating since January '93 at Gran Sasso National Laboratories as a thermal detector to search for neutrinoless decay of130Te. The reduction of environmental radioactivity is accomplished by means of a 10 cm thick external lead shielding and a plexiglas box against222Rn, while an inner ultra-low activity lead shield of at least 3.5 cm in every direction suppresses the residual local radioactivity near the crystal. The good energy resolution and the peak-to-Compton efficiency of the detector allow to understand the main features of the residual background. In particular, we are able to reach a sensitivity in the internal contamination of238U and232Th of the crystal of the order of 10–13 g/g, better than that of modern mass spectroscopy methods. Pulse acquisition and analysis techniques are reported and discussed.Present limit on neutrinoless decay half-life time of130Te obtained with this detector is of the order of 1022y at 68% C.L., exceeding by one order of magnitude the value quoted by the inclusive geochemical measurements, which have therefore to be attributed mainly to the 2-neutrino channel.On leave from the Dept. of Physics, University of Zaragoza |
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