CUORE (Cryogenic Underground Observatory for Rare Events) is an experiment proposed to infer the effective Majorana mass of the electron neutrino from measurements on neutrinoless double beta decay (0νDBD). The goal of CUORE is to achieve a background rate in the range 0.001 to 0.01 counts/keV/kg/y at the 0νDBD transition energy of 130Te (2528 keV). The proposed experiment, to be mounted in the underground Gran Sasso INFN National Laboratory, Italy, is realized by cooling about 1000 TeO2 bolometers, of 750 g each, at a temperature of 10mK. We will describe the experiment, to be cooled by an extremely powerful dilution refrigerator, operating with no liquid helium, and the main experimental features designed to assure the predicted sensitivity. We present moreover the last results of a small scale (40.7 kg) 0νDBD experiment carried on in the Gran Sasso Laboratory (CUORICINO).
The MiniGRAIL detector was improved. The sphere was replaced by a slightly larger one, having a diameter of 68 cm (instead of 65 cm), reducing the resonant frequency by about 200 Hz to around 2.9 kHz. The last four masses of the attenuation system were machined to increase their resonant frequency and improve the attenuation around the resonant frequency of the sphere. In the new sphere, six holes were machined on the TIGA positions for easy mounting of the transducers. During the last cryogenic run, two capacitive transducers and a calibrator were mounted on the sphere. The first transducer was coupled to a double-stage SQUID amplifier having a commercial quantum design SQUID as a first stage and a DROS as a second stage. The second transducer was read by a single-stage quantum design SQUID. During the cryogenic run, the sphere was cooled down to 4 K. The two-stage SQUID had a flux noise of about 1.6 μϕ0 Hz−1/2. The detector was calibrated and the sensitivity curve of MiniGRAIL was determined.
The latest results of the measurements on the vibration isolation system of MiniGRAIL at room temperature as well as an overview of the results of the ultra-cryogenic tests with the dilution refrigerator are presented. Two types of capacitive transducers have been developed and tested separately in a cryogenic set-up. The rosette-design transducers have been mounted on the sphere and tested at low temperature. We also report the progress in developing a two-mode inductive transducer with an Al5056 resonator as a second resonating mass and a Nb film coil as superconducting pick-up loop. Furthermore, we developed and tested two double-SQUID systems based on two types of dc SQUIDs as sensors and a DROS as the preamplifier stage.
A new nuclear demagnetization system coupled to a powerful dilution refrigerator and a vector magnet was successfully built and operated. Our aim was to construct a versatile, modular cryostat, with a large experimental space providing an excellent platform for various types of ultralow temperature measurements. A powerful dilution unit allows us to cool the mixing chamber down to 3 mK and to precool a massive copper (∼90 mol) nuclear stage in a field of 9 T to 8 mK in 100 h. After demagnetization the lowest temperature of the copper stage measured by a Pt thermometer was 50.9 μK in a field of 20 mT. The cryostat is integrated with a 8 T-4 T vector magnet system. The refrigerator is provided with a 50 mm central clear shot tube allowing the insertion of a top-loading probe to cool down samples for measurements inside the vector magnet bore in a reasonably short time of about 4 hours. The system will be used to study quantum critical behavior of heavy fermion compounds.
First Results on Neutrinoless Double Beta Decay of 130 Te with the Calorimetric Cuoricino Experiment C. Arnaboldi a , D.R. Artusa b , F.T. Avignone III b , M.Balata c , I.Bandac b , M.Barucci d , J.W.Beeman e , C.Brofferio a , C.Bucci c , S.Capelli a , F.Capozzi a , L.Carbone a , S.Cebrian f , O. Cremonesi a , R.J.Creswick b , A. de Waard i , H.A.Farach b , A.Fascilla h , E. Fiorini a,1 , G.Frossati i , A. Giuliani h , P.Gorla a,f,3 , E.E.Haller e,g , R.J.McDonald e A.Morales f , E.B.Norman e , A. Nucciotti a , E. Olivieri d , E.Palmieri j , E.Pasca d , M. Pavan a , M. Pedretti h , G. Pessina a , S.Pirro c , C.Pobes c,2 E. Previtali a , M.Pyle c , L.Risegari d , C.Rosenfeld b , S.Sangiorgio h , M. Sisti a , A.R.Smith e , L.Torres a,f,3 , G.Ventura d . a Dipartimento b Department di Fisica dell’Universit` di Milano-Bicocca e Sezione di Milano a dell’INFN, Milan I-2016, Italy of Physics and Astronomy , University of South Carolina, Columbia , South Carolina,29208,USA Nazionali del Gran Sasso, I-67010, Assergi (L’Aquila), Italy di Fisica dell’Universit` di Firenze e Sezione di Firenze dell’INFN, a Firenze I-50125, Italy de Fisica Nuclear y Alta Energias, Universitad de Zaragoza, 50009 Zaragoza , Spain c Laboratori d Dipartimento e Lawrence f Laboratorio g Dept.of Berkeley National Laboratory , Berkeley, California 94720, USA Material Science and Enginering,Univ.California,Berkeley,California 94720 USA h Dipartimento i Kamerling di Scienze Chimiche, Fisiche e Matematiche dell’Universit` a dell’Insubria e Sezione di Milano dell’INFN, Como I-22100, Italy Onnes Laboratory, Leiden University, 2300 RAQ,Leiden, the Netherlands Nazionali di Legnaro, I-35020 Legnaro,(padova),Italy j Laboratori Abstract The first results are reported on the limit for neutrinoless double decay of 130 Te Preprint submitted to Elsevier Preprint 4 December 2003
HiSPARC (High-School Project on Astrophysics Research with cosmics) is a project that envisages the use of a large array of cosmic ray detectors placed at high-schools and scientific institutions in the Netherlands in order to measure high-energy cosmic ray showers. Besides contributing to the HiSPARC project, Leiden University also uses the cosmic ray detectors as veto for the resonant gravitational wave antenna MiniGRAIL.
Internal friction effects are responsible for line widening of the acoustic resonance frequencies in mechanical oscillators and result in damped oscillations of its eigenmodes with a decay time Q/ω. We study the solutions to the equations of motion for the case of spherical oscillators, to be used as the next generation of acoustic gravitational wave detectors, based on various different assumptions about the material's constituent equations. Quality factor dependence on mode frequency is determined in each case, and a discussion of its applicability to actual gravitational wave detectors is made on the basis of available experimental evidence.
Internal friction effects are responsible for line widening of the resonance frequencies in mechanical oscillators and result in damped oscillations of its eigenmodes with a decay time Q/ω. We study the solutions to the equations of motion for the case of spherical oscillators, to be used as next generation of acoustic gravitational wave detectors, based on various different assumptions about the material's constituent equations. Quality factor dependence on mode frequency is determined in each case, and a discussion of its applicability to actual gravitational wave detectors is made on the basis of available experimental evidence.
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