31 research outputs found

    Avaliação ultrassonográfica do bulbo ocular em cães submetidos à facoemulsificação com ou sem implante de lente intraocular

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    Este trabalho objetivou descrever e comparar as alterações ultrassonográficas encontradas em bulbos oculares de cães submetidos à facoemulsificação, com ou sem implante de lente intraocular (LIO), no intuito de auxiliar no diagnóstico de alterações decorrentes da cirurgia e do implante da LIO, bem como sua correspondência com alterações clínicas. Dezenove cães portadores de catarata (21 olhos) foram submetidos ao procedimento de facoemulsificação e avaliados no pós-operatório tardio, aos cinco anos de evolução. Constituíram-se três grupos experimentais: afácicos (CA), formados por 11 cães; pseudofácicos (PP), com implante de duas LIOs em piggyback (n=5); e pseudofácicos (PL), com implante de uma LIO veterinária (n=5). Após exame oftálmico, todos foram submetidos ao exame ultrassonográfico, sob anestesia tópica, com transdutor linear multifrequencial de 10MHz; adicionalmente foram avaliadas medidas biométricas dos bulbos do olho. As principais alterações observadas foram: luxação da LIO, descolamento de retina, hialose asteroide e degeneração vítrea. O exame ultrassonográfico mostrou-se como excelente ferramenta diagnóstica e possibilitou a confirmação e a classificação dessas alterações. Na biometria ocular, pelas medidas entre o corpo ciliar e a câmara vítrea, o implante em piggyback resultou em redução destas em relação aos demais procedimentos instituídos, não havendo diferença ente o comprimento axial e a câmara anterior

    New results from the CUORE experiment

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    International audienceThe Cryogenic Underground Observatory for Rare Events (CUORE) is the first cryogenic experiment searching for neutrinoless double-beta (0νββ0\nu\beta\beta) decay that has been able to reach the one-ton scale. The detector, located at the Laboratori Nazionali del Gran Sasso in Italy, consists of an array of 988 TeO2_2 crystals arranged in a compact cylindrical structure of 19 towers. Following the completion of the detector construction in August 2016, CUORE began its first physics data run in 2017 at a base temperature of about 10 mK. Following multiple optimization campaigns in 2018, CUORE is currently in stable operating mode. In 2019, CUORE released its 2\textsuperscript{nd} result of the search for 0νββ0\nu\beta\beta with a TeO2_2 exposure of 372.5 kg\cdotyr and a median exclusion sensitivity to a 130^{130}Te 0νββ0\nu\beta\beta decay half-life of 1.710251.7\cdot 10^{25} yr. We find no evidence for 0νββ0\nu\beta\beta decay and set a 90\% C.I. (credibility interval) Bayesian lower limit of 3.210253.2\cdot 10^{25} yr on the 130^{130}Te 0νββ0\nu\beta\beta decay half-life. In this work, we present the current status of CUORE's search for 0νββ0\nu\beta\beta, as well as review the detector performance. Finally, we give an update of the CUORE background model and the measurement of the 130^{130}Te two neutrino double-beta (2νββ2\nu\beta\beta) decay half-lif

    Search for Majorana neutrinos exploiting millikelvin cryogenics with CUORE

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    International audienceThe CUORE experiment finds no evidence for neutrinoless double beta decay after operating a large cryogenic TeO2_{2} calorimeter stably for several years in an extreme low-radiation environment at a temperature of 10 millikelvin

    Measurement of the 2νββ2\nu\beta\beta Decay Half-Life of 130Te^{130}\mathrm{Te} with CUORE

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    International audienceWe measured two-neutrino double beta decay of Te130 using an exposure of 300.7 kg yr accumulated with the CUORE detector. Using a Bayesian analysis to fit simulated spectra to experimental data, it was possible to disentangle all the major background sources and precisely measure the two-neutrino contribution. The half-life is in agreement with past measurements with a strongly reduced uncertainty: T1/22ν=7.71-0.06+0.08(stat)-0.15+0.12(syst)×1020  yr. This measurement is the most precise determination of the Te130 2νββ decay half-life to date

    New results from the CUORE experiment

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    International audienceThe Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrino-less double-beta (0νββ) decay that has been able to reach the one-ton scale. The detector, located at the Laboratori Nazionali del Gran Sasso in Italy, consists of an array of 988 TeO2 crystals arranged in a compact cylindrical structure of 19 towers. Following the completion of the detector construction in August 2016, CUORE began its first physics data run in 2017 at a base temperature of about 10 mK. Following multiple optimization campaigns in 2018, CUORE is currently in stable operating mode. In 2019, CUORE released its second result of the search for 0νββ corresponding to a TeO2 exposure of 372.5 kg⋅yr and a median exclusion sensitivity to a 130Te 0νββ decay half-life of 1.7 ⋅ 1025 yr. We find no evidence for 0νββ decay and set a 90% C.I. Bayesian lower limit of 3.2 ⋅ 1025 yr on the 130Te 0νββ decay half-life. We present the current status of CUORE’s search for 0νββ. We give an update of the CUORE background model and the measurement of the 130Te two neutrino double-beta (2νββ) decay half-life. Eventually, we show the preliminary results on half-life limits from the analysis of 130Te 0νββ and 2νββ decay to the first 0+ excited state of 130Xe

    Status and prospects of discovery of 0νββ decay with the CUORE detector

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    International audienceIn this contribution we present the achievements of the CUOREexperiment so far. It is the first tonne-scale bolometric detector and it is in stabledata taking since 2018. We reached to collect about 1800 kg×yr of exposure ofwhich more than 1ton×year have been analysed. The CUORE detector is meantto search for the neutrinoless double ß decay (0.ßß) of the 130Te isotope. This isa beyond Standard Model process which could establish the nature of the neutrinoto be Dirac or a Majorana particle. It is an alternative mode of the two-neutrinosdouble ß decay, a rare decay which have been precisely measured by CUORE inthe 130Te. We found no evidence of the 0.ßß and we set a Bayesian lower limitof 2.2×1025yr on its half-life. The expertise achieved by CUORE set a milestonefor any future bolometric detector, including CUPID, which is the planned nextgeneration experiment searching for 0.ßß with scintillating bolometers

    An Energy-dependent Electro-thermal Response Model of CUORE Cryogenic Calorimeter

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    International audienceThe Cryogenic Underground Observatory for Rare Events (CUORE) is the most sensitive experiment searching for neutrinoless double-beta decay (0νββ0\nu\beta\beta) in 130Te^{130}\text{Te}. CUORE uses a cryogenic array of 988 TeO2_2 calorimeters operated at \sim10 mK with a total mass of 741 kg. To further increase the sensitivity, the detector response must be well understood. Here, we present a non-linear thermal model for the CUORE experiment on a detector-by-detector basis. We have examined both equilibrium and dynamic electro-thermal models of detectors by numerically fitting non-linear differential equations to the detector data of a subset of CUORE channels which are well characterized and representative of all channels. We demonstrate that the hot-electron effect and electric-field dependence of resistance in NTD-Ge thermistors alone are inadequate to describe our detectors' energy dependent pulse shapes. We introduce an empirical second-order correction factor in the exponential temperature dependence of the thermistor, which produces excellent agreement with energy-dependent pulse shape data up to 6 MeV. We also present a noise analysis using the fitted thermal parameters and show that the intrinsic thermal noise is negligible compared to the observed noise for our detectors
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