[en] Neutrinos have recently provided us with the first tangible evidence of phenomena beyond the reach of our theory of the laws of particle physics, the remarkably predictive 'Standard Model'. The positive observation of neutrino oscillations in atmospheric neutrinos and in solar neutrinos gives new motivations for more sensitive searches. Unfortunately the oscillation experiments can only provide data on the mass differences of the neutrino mass-eigenstates. The absolute scale can only be obtained from direct mass measurements, ³H end point measurements for example, or in the case of Majorana neutrinos, more sensitively by neutrinoless double beta decay. In fact, recently published constraints on the mixing angles of the neutrino mixing matrix make a strong case that if neutrinos are Majorana particles, there are many scenarios in which next generation double-beta decay experiments should be able to observe the phenomenon and measure the effective Majorana mass of the electron neutrino, which would provide a measure of the neutrino mass scale. The interest for next generation double beta decay experiments is growing up, for if the mass scale is below ∼ 0.2 eV, double beta decay may be the only hope for measuring it. After a short theoretical overview, the general aspects pertaining to the different experimental approaches will be presented. In the context of their claimed sensitivity most of the proposed future experiments will be discussed. (author)

[en] Cryogenic vibrations generated by continuously filled 1K Pots are a well known source of noise in all cryogenic experiments using dilution refrigerators. Starting from recent developments we realized a non invasive modification to the cryostat that completely eliminated vibrations, thermalizing the helium coming from the main bath at the pot temperature. We describe the new experimental setup and complete study of the phenomena

[en] Neutrinos have recently provided us with the first tangible evidence of phenomena beyond the reach of our theory of the laws of particle physics, the remarkably predictive ''Standard Model''. The positive observation of oscillations in atmospheric and in solar neutrinos gives new motivations for more sensitive searches. Unfortunately, the oscillation experiments can only provide data on the squared mass differences of the neutrino mass eigenstates, while the absolute scale can only be obtained from direct mass measurements, ³H end point measurements for example or, in the case of Majorana neutrinos, more sensitively by neutrinoless double beta decay. In fact, recently published constraints on the mixing angles of the neutrino mixing matrix make a strong case that if neutrinos are Majorana particles, there are many scenarios in which next-generation double beta decay experiments should be able to observe the phenomenon, trying to disentangle the mass scale of the neutrinos. The interest for next-generation double beta decay experiments is growing, for if the mass scale is below ∝0.2 eV, double beta decay may be the only hope for measuring it. (orig.)

[en] The noise induced by vibrations represents a serious problem for large thermal detectors. This noise affects the energy resolution of the detectors resulting, in most cases, in a large decrease of the measurement live time. A new damping system was constructed and tested to avoid this problem in view of the CUORE Experiment. Starting from the CUORICINO Experiment, we developed a more efficient double stage damping system inside the CUORE R and D cryostat. The results obtained by direct comparison with the CUORICINO array show that the noise induced by vibration in the new setup is three orders of magnitude smaller with respect to CUORICINO

[en] In this paper we discuss the perspectives for a new generation of neutrino mass experiments using thermal detectors to reach interesting sensitivities before and after the KATRIN experiment. By scaling the performance of the present Milano neutrino mass experiment with Monte Carlo simulations, we show how a new experiment can validate the present limit of few eV set by spectrometers before the KATRIN experiment starts. We also show how such a result can be used to design a very large thermal detector experiment to reach sensitivities beyond the KATRIN expected one

[en] We report on a new front-end system developed to readout an array of large mass bolometers. The front-end allows setting all the necessary parameters for each detector by remote control. A special circuit, also fired remotely, has been developed in order to adjust the output voltage, allowing the DC coupling to the detector

[en] The front-end approach for the readout of two arrays of bolometric detectors is described. The first front-end is for an array of μ-bolometers, while the second is for an array of macro-bolometers. Analogies and differences in the adopted strategies are put into evidence

[en] In this paper we want to discuss the results obtained on bolometer detectors in the last year by the Milano Group. At first we will show the results on double decay of ¹³⁰Te obtained running an array of twenty cryogenic detectors for about 1450h (0.31Kg/y of ¹³⁰Te under test). The set-up is made with crystals of TeO₂ of 340 grams each. It was run in the Gran Sasso Underground Laboratory at a depth of about 3500 m.w.e. By recording the pulses of each detector, in anticoincidence with the others, a 90% c.l. lower limit of 0.87x10²³ years has been obtained on neutrinoless ββ decay of ¹³⁰Te. Then we will show the exceptional energy resolution of two bolometers composed of tin absorbers and NTD Ge thermistors. They have been fabricated in preparation of experiments in nuclear and subnuclear physics. Both detectors fully resolve the two K_α1 and K_α2 lines of ⁵⁵Mn. The deconvolved FWHM resolution in this energy region ranges from 4.5 to 5.7 eV, according to different intrinsic measured value of those lines

[en] Present results on neutrinoless double beta decay of ¹³⁰Te obtained with an array of 20 cryogenic detectors are presented. The setup consists of 20 crystals of tellurium oxide of 340 g each, corresponding to the largest presently operating cryogenic mass. Combining the results of the few runs obtained with the same array, corresponding to 1.5 kg yr, a limit on neutrinoless double beta decay half-life of 9.5x10²² yr (90% CL) has been obtained. On the basis of the results obtained with the MI-BETA experiment, we propose a construction of a 42 kg array of 56 TeO₂ bolometers (CUORICINO project) to extend the sensitivity of the present experiment, and as a first test for CUORE. Thanks to an innovative technique of vibration reduction and despite the high mass (750 g instead of the 340 g of the presently running detectors) we reached an energy resolution of 3.9 keV FWHM at 2615 keV decreasing to 1.4 keV at low energies

[en] We report on the final results of a series of experiments on double beta decay of ¹³⁰Te carried out with an array of twenty cryogenic detectors. The set-up is made with crystals of TeO₂ with a total mass of 6.8 kg, the largest operating one for a cryogenic experiment. Four crystals are made with isotopically enriched materials: two in ¹²⁸Te and two others in ¹³⁰Te. The remaining ones are made with natural tellurium, which contains 31.7% and 33.8% ¹²⁸Te and ¹³⁰Te, respectively. The array was run under a heavy shield in the Gran Sasso Underground Laboratory at a depth of about 3500 m.w.e. By recording the pulses of each detector in anticoincidence with the others a lower limit of 2.1x10²³ years has been obtained at the 90% C.L. on the lifetime for neutrinoless double beta decay of ¹³⁰Te. In terms of effective neutrino mass this leads to the most restrictive limit in direct experiments, after those obtained with Ge diodes. Limits on other lepton violating decays of ¹³⁰Te and on the neutrinoless double beta decay of ¹²⁸Te to the ground state of ¹²⁸Xe are also reported and discussed. An indication is presented for the two neutrino double beta decay of ¹³⁰Te. Some consequences of the present results in the interpretation of geochemical experiments are discussed