Present status of MI-BETA cryogenic experiment and preliminary results forCUORICINO

Present results on neutrinoless double beta decay of Te-130 obtained with a n array of 20 cryogenic detectors are presented. The setup consists of 20 c rystals of tellurium oxide of 340 g each, corresponding to the largest pres ently operating cryogenic mass. Combining the results of the few runs obtai ned with the same array, corresponding to 1.5 kg yr, a limit on neutrinoles s double beta decay half-life of 9.5 x 10(22) yr (90% CL) has been obtained . On the basis of the results obtained with the MI-BETA experiment, we prop ose a construction of a 42 kg array of 56 TeO2 bolometers (CUORICINO projec t) to extend the sensitivity of the present experiment, and as a first test for CUORE. Thanks to an innovative technique of vibration reduction and de spite the high mass (750 g instead of the 340 g of the presently running de tectors) we reached an energy resolution of 3.9 keV FWHM at 2615 keV decrea sing to 1.4 keV at low energies. (C) 2000 Elsevier Science B.V. All rights reserved.