323 research outputs found
Aromatic characterization of Moscato Giallo by GC-MS/MS and stable isotopic ratio analysis of the major volatile compounds
Among the Moscato grapes, Moscato Giallo is a winegrape variety characterized by a highcontent of free and glycosylated monoterpenoids, which gives very aromatic wines. Thearomatic bouquet of Moscato Giallo is strongly influenced by the high concentration of linalool, geraniol, linalool oxides, limonene, α-terpineol, citronellol, HO-trienol, HO-diols, 8-Hydroxylinalool, geranic acid and β-myrcene, that give citrus, rose, and peach notes. Except the quali-quantitative analysis, no investigations regarding the isotopic values of the target volatile compounds are documented in literature. Stable isotope ratio analysis represents a modern and powerful tool used by the laboratories responsible for official consumer protection, for the food quality and genuineness assessment. In this study, samples of Moscato Giallo were collected during the harvest season in 2019 from two Italian regions:Trentino – Alto Adige and Veneto, known lands for the cultivation of this aromatic variety. The flavor compounds were extracted from grapes and wines, after alcoholic fermentation of grape juice, and analysed by GC-MS/MS. The results confirmed the presence of typical terpenoids both in free and glycosylated form, responsible for the characteristic aroma of Moscato Giallo variety. The aromatic compounds were also analysed by GC-C\Py-IRMS for a preliminary investigation. The compound-specific isotope ratio analysis allowed to determine the carbon (δ13C) and hydrogen (δ2H) isotopic signatures of the major volatile compounds for the first time
A search for neutrinoless double beta decay of 130Te with a thermal detector
Abstract A 73.1 g TeO2 bolometric detector has been operating for more than two months at about 16 mK in a specially constructed low activity dilution refrigerator installed in the Gran Sasso Underground Laboratory and shielded against environmental radioactivity. Its energy resolution is comparable with that of a Ge diode. A spectrum of the thermal pulses collected in 1389 h of effective running time shows no evidence for neutrinoless double beta decay of 130Te. The corresponding lower limit of the lifetime is three orders of magnitude more stringent than those obtained for the some nucleus with conventional techniques. It also exceeds the value for the inclusive (two neutrino and neutrinoless) lifetime obtained by geochemical searches. Double beta decay of 130Te has therefore to be attributed mainly to the two neutrino channel
Large calorimetric devices for double beta decay and dark matter
Abstract The use of cryogenic thermal particle detectors permits the realization of detectors of various compositions, various sizes and very good energy resolution. In particular these characteristics are very promising for the realization of double beta decay and dark matter search experiments. Our group is mainly interested in the study of double beta decay of 130Te and 116Cd. For tellurium we have realized various detectors using TeO2 crystals, the final one with a mass of 334 g. For cadmium a CdWO4 crystal of 58 g has been used in various tests. The double beta decay measurement has been performed in the Gran Sasso Underground Laboratory. Measurements on the 334 g TeO2 crystal have been performed for 3000 h. Detector resolution is around 10 keV FWHM and the internal contamination of 238U and 232Th in the crystal is of the order of 10−13 g/g. A lower limit on the half-life of neutrinoless double beta decay for 130Te of 8.2 × 1021 yr (90% CL) is measured. The test measurements of CdWO4 reach an energy resolution of about 5 keV FWHM with a very high efficiency to gamma ray detection. A limit on the neutrinoless channel of 7 × 1019 yr (90% CL) is evaluated in 340 h. In this test an end point energy of 318.8 ± 1.4 ± 5 keV and a half-life of (9.3 ± 0.5 ± 1) × 1015 yr for the beta decay of 113Cd are also measured. The last part of the paper is dedicated to a brief discussion of our proposal for the solar neutrino flux measurement and for the search of dark matter using cryogenic detectors
Optimization of Si-Implanted Thermistors for High Resolution Calorimeters to be used in a Neutrino Mass Experiment
A procedure of optimization of Si-implanted thermistors was started, with the final aim to develop bolometers with a resolution of a few eV in the keV range. The initial approach was to assume that a thermal decoupling between phonons and hopping electrons establishes inside the thermistors, with consequent reduction of the sensitivity and incomplete transfer of the particle generated phonons to the conduction electrons. This assumption however failed in explaining the collected experimental data, which can be described much more satisfactorily introducing an electric field dependance of the thermistor resistance. This alternative interpretation modifies the parameter choice for an optimum devic
Cryogenic thermal detectors as a powerful way to analyse internal activities
Abstract The Milano group is using an array of four crystals of TeO 2 , 334 g each, to search for neutrinoless double beta decay of 130 Te [A. Alessandrello et al., Phys. Lett. B 335 (1994) 519; Proc. 4th Int. Workshop on Theoretical and Phenomenological Aspects of Underground Physics — TAUP 95, to be published in Nucl. Phys. B (Proc. Suppl)]. The detectors are operating in a dilution refrigerator installed in the Underground National Laboratory of Gran Sasso specially built with low activity materials. Due to the low external background and the good energy resolution it is possible to obtain precise measurements of some internal contaminations of the detector itself. An analysis of a contamination of 210 Po and of the decay of 123 Te is presented
Preliminary results on double beta decay of 130Te with an array of twenty cryogenic detectors
Preliminary results on double beta decay of 130 Te obtained in the first run of an array of twenty cryogenic detectors are presented. The set-up is made with crystals of TeO of 340 grams each corresponding to the largest presently operating 2 cryogenic mass. It 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 90% c.l. lower limit of 5.6 = 10 22 years has been obtained on the lifetime for neutrinoless double beta decay of 130 Te in a preliminary test run, corresponding to about one week of effective running time. No evidence is also found for double beta decay to the first excited 2 q state of 130 Xe with a 90% c.l. lower limit of 1.7 = 10 22 years on that lifetime. Some consequences of the present results in th
A new search for neutrinoless ββ decay with a thermal detector
Abstract A 334 g TeO2 crystal has been operated at a temperature of around 10 mK for more than one year in a low intrinsic radioactivity dilution refrigerator installed in the Gran Sasso Underground Laboratory. From the spectrum collected in 9234 h of effective running time we improve our limit on neutrinoless double beta decay of 130Te by an order of magnitude with respect to our previous experiment. It is the most stringent on this nucleus and excludes a large contribution of the neutrinoless mode to the rate of double beta decay found in geochemical experiments. Upper limits on the effective neutrino mass and on the contributions of right banded currents are given
Preliminary results on the performance of a TeO2 thermal detector in a search for direct interactions of WIMPS
Abstract During a Double Beta Decay experiment performed at Laboratori Nazionali del Gran Sasso, a 1548 hours background spectrum was collected with a 340 g TeO2 thermal detector. An analysis of this spectrum has been carried out to search for possible WIMP signals. The values for parameters which are essential in the search for WIMPs, like energy resolution (2 keV), energy threshold (13 keV) and nuclear recoil quenching factor (≥ 0.93) have been experimentally determined and are discussed in detail. The spectrum of recoils induced by α decays has been directly observed for the first time in coincidence with the α particle pulse. Preliminary limits on the spin-independent cross sections of WIMPs on Te and O nuclei have been obtained
A scintillating bolometer for experiments on double beta decay
Abstract The scintillation yields of CaF 2 crystals with different doping concentration of Europium have been measured at low temperatures and their bolometric behavior has been investigated. After these studies we have constructed the first "scintillating bolometer" where the heat and scintillation pulses produced by charged particles are simultaneously recorded. With this method a strong suppression of the background from α -particles in the energy region of interest for searches on double beta decay of 48 Ca can be achieved
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