Paolo Gorla
Laboratori Nazionali del Gran Sasso
Abstract:
In the last few years very important results have been reached in the study of neutrino and of its proprieties. Nevertheless there are still two important missing pieces in the neutrino puzzle: the understanding of its nature (Dirac or Majorana) and the measurement of the absolute mass scale. Neutrinoless Double Beta Decay (DBD-0nu) is a unique tool to discriminate the neutrino nature and eventually to measure its absolute mass. The CUORE (Cryogenic Underground Observatory for Rare Events) experiment is a TeO2 array of 988 bolometric detectors, which aims to reach a sensitivity on the neutrino mass better than 50 meV.
I will report the R\&D effort in improving detector sensitivity on the detectors
performance and on background reduction. The starting point of these activities
is the CUORICINO experiment, a prototype of CUORE, built with 62 TeO2 bolometers,
presently running in the LNGS underground site. Background is the only parameter
that can be tuned by orders of magnitude allowing a sizable improvement of the
experimental sensitivity. I will report the low temperature tests that have
been conducted obtaining a background reduction from the present CUORICINO level
of 0.18 counts/keV/kg/y to about 0.025 counts/keV/kg/y. Finally I will present
a new detector holder and setup to improve the detector resolution. This setup
was tested with a 12 detector array showing a higher uniformity of resolution
compared to CUORICINO, reducing the deviation from the mean resolution from
40% to 14%.