450 research outputs found
Monolithic current-sensitive preamplifier for the Accordion LAr calorimeter
Abstract Monolithic current-sensitive preamplifiers matching large detector capacitances, suitable for the Accordion LAr calorimeter prototype, have been designed and fabricated in an ion-implanted GaAs MESFET process. After pulse shaping with an CR-RC 2 filter, the equivalent noise charge is at least a factor of 2 lower than the value reached so far with existing hybrids circuits, without increasing the power dissipation. This preamplifier has a fast response and large dynamic range. Results show that it is still possible to further reduce the noise and extend the dynamic range; this is likely to be obtained in a new version presently being developed
Monitoring DC anode current of a grounded-cathode photomultiplier tube
Abstract The Pierre Auger Observatories (PAO) for the highest energy cosmic rays will make use of both the Cherenkov and Air Fluorescence techniques. Surface Detectors (SD) and Fluorescence Detectors (FD) will have to operate in a desert-type environment during at least 15 years. In order to avoid dust deposition, due to electrostatics, and other practical inconveniences derived from biasing the cathode with a negative potential, the 15 000 PMTs of the FD will operate in the grounded cathode configuration. Despite the fact that the anodes will remain at high voltage with respect to ground, the DC anode current, which varies with background light, will have to be recorded. We have developed a current monitoring system based on a novel optocoupled feedback circuit that allows sensitive, linear, and temperature-independent measurements of the DC anode current. A distinctive feature of this circuit is that it uses optical coupling between passive components at high voltage and active components near the ground potential. This represents a substantial improvement over classical solutions which require the supply of power to an active circuit at high voltage. We report on the first tests performed with both active and passive biasing networks which demonstrate the validity of this new method
Elemental and isotopic profiling: a tool for distinguishing the botanical origin of oenological tannins
Much contemporary evidence underscores the pathophysiological importance of Ca2+ handling by acidic organelles such as lysosomes. Whereas our knowledge of how Ca2+ is released from these acidic Ca2+ stores (the ‘outs’) is advancing, we know relatively little about how Ca2+ uptake is effected (the ‘ins’). Here I highlight new work identifying animal Ca2+/H+ (CAX) exchangers that localize to acidic organelles, mediate Ca2+ uptake and regulate cell migration in vivo. Continued molecular definition of the acidic Ca2+ store toolkit provides new insight into Ca2+-dependent function
Monolithic GaAs current-sensitive cryogenic preamplifier for calorimetry applications
We have realized low-noise monolithic GaAs preamplifiers using ion- implanted technology , to operate under low temperature and high radiation field conditions. The evaluation of noise, amplitude and timing distributions of a batch taken after first mass-production run is presented. The current-sensitive preamplifier is linear up to 8 mA of input current and able to cope a 2.2 nF detector capacitance, showing fast response ( GBW product ∼ 1.7GHz) and very low series noise. Very good noise performance at LAr temperature is obtained by using large area MESFET ( l · w = 3. 24000μm 2 ) as a head transistor, which exhibits at 8mA standing current and only 10mW power dissipation, intrinsic gain μ = g m · r ds = 15 and noise referred to the input 0.30 ÷ 0.35 H z n ¯ V According to our estimation, second stage noise contribution is negligible. Radiation damage from neutrons and γ-irradiations as well as protection network against HV discharges are discussed
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
Educational interventions to improve maternal‐foetal outcomes in women with gestational diabetes
To evaluate improvement in gestational diabetes (GDM) outcomes for mothers and their offspring induced by education provided to the healthcare team (HCTM) and women with GDM, plus coordination between primary care units (PCU) and highly complex maternity (HCM) facilities.Fil: Gorbán de Lapertosa, Silvia. Universidad Nacional del Nordeste; ArgentinaFil: Elgart, Jorge Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Endocrinología Experimental y Aplicada. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Endocrinología Experimental y Aplicada; ArgentinaFil: González, Claudio D.. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; ArgentinaFil: Alvariñas, Jorge. Gobierno de la Ciudad Autónoma de Buenos Aires. Hospital General de Agudos Enrique Tornú; ArgentinaFil: Camin, Paula. Gobierno de la Ciudad Autonoma de Buenos Aires. Hospital General de Agudos Doctor Cosme Argerich.; ArgentinaFil: Mezzabotta, Leonardo. Gobierno de la Ciudad Autonoma de Buenos Aires. Hospital General de Agudos Doctor Cosme Argerich.; ArgentinaFil: Salzberg, Susana. Instituto Centenario, Department Of Medical Research; Argentina. Instituto Centenario, Salud y Calidad de Vida; ArgentinaFil: Gagliardino, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Endocrinología Experimental y Aplicada. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Endocrinología Experimental y Aplicada; Argentin
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
- …