  Bolometers are ideal devices in the search for neutrinoless Double Beta
Decay. Enlarging the mass of individual detectors would simplify the
construction of a large experiment, but would also decrease the background per
unit mass induced by alpha-emitters located close to the surfaces and
background arising from external and internal gamma's. We present the very
promising results obtained with a 2.13 kg TeO2 crystal. This bolometer, cooled
down to a temperature of 10.5 mK in a dilution refrigerator located deep
underground in the Gran Sasso National Laboratories, represents the largest
thermal detector ever operated. The detector exhibited an energy resolution
spanning a range from 3.9 keV (at 145 keV) to 7.8 keV (at the 2615 gamma-line
of 208Tl) FWHM. We discuss the decrease in the background per unit mass that
can be achieved increasing the mass of a bolometer.
