6,583 research outputs found

    Rocket experiments for spectral estimation of electron density fine structure in the auroral and equatorial ionosphere and preliminary results

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    Sounding rockets equipped to monitor electron density and its fine structure were launched into the auroral and equatorial ionosphere in 1980 and 1983, respectively. The measurement electronics are based on the Langmuir probe and are described in detail. An approach to the spectral analysis of the density irregularities is addressed and a software algorithm implementing the approach is given. Preliminary results of the analysis are presented

    Measurements and optimization of the light yield of a TeO2_2 crystal

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    Bolometers have proven to be good instruments to search for rare processes because of their excellent energy resolution and their extremely low intrinsic background. In this kind of detectors, the capability of discriminating alpha particles from electrons represents an important aspect for the background reduction. One possibility for obtaining such a discrimination is provided by the detection of the Cherenkov light which, at the low energies of the natural radioactivity, is only emitted by electrons. This paper describes the method developed to evaluate the amount of light produced by a crystal of TeO2_2 when hit by a 511 keV photon. The experimental measurements and the results of a detailed simulation of the crystal and the readout system are shown and compared. A light yield of about 52 Cherenkov photons per deposited MeV was measured. The effect of wrapping the crystal with a PTFE layer, with the aim of maximizing the light collection, is also presented

    High prevalence of anti-hepatitis e virus antibodies among blood donors in central Italy, february to march 2014

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    Prevalence of anti-hepatitis E virus (HEV) antibodies is highly variable in developed countries, which seems partly due to differences in assay sensitivity. Using validated sensitive assays, we tested 313 blood donors attending a hospital transfusion unit in central Italy in January and February 2014 for anti-HEV IgG and IgM and HEV RNA. Data on HEV exposure were collected from all donors. Overall anti-HEV IgG prevalence was 49% (153/313). Eating raw dried pig-liver sausage was the only independent predictor of HEV infection (adjusted prevalence rate ratio = 2.14; 95% confidence interval: 1.23–3.74). Three donors were positive for either anti-HEV IgM (n = 2; 0.6%) or HEV RNA (n = 2; 0.6%); they were completely asymptomatic, without alanine aminotransferase (ALT) abnormalities. Of the two HEV RNA-positive donors (both harbouring genotype 3), one was anti-HEV IgG- and IgM-positive, the other was anti-HEV IgG- and IgM-negative. The third donor was positive for anti-HEV IgG and IgM but HEV RNA-negative. HEV infection is therefore hyperendemic among blood donors (80% men 18–64 years-old) from central Italy and associated with local dietary habits. Nearly 1% of donors have acute or recent infection, implying potential transmission to blood recipients. Neither ALT nor anti-HEV IgM testing seems useful to prevent transfusion-transmitted HEV infection. © 2016, European Centre for Disease Prevention and Control

    TeO2_2 bolometers with Cherenkov signal tagging: towards next-generation neutrinoless double beta decay experiments

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    CUORE, an array of 988 TeO2_2 bolometers, is about to be one of the most sensitive experiments searching for neutrinoless double-beta decay. Its sensitivity could be further improved by removing the background from α\alpha radioactivity. A few years ago it has been pointed out that the signal from ÎČ\betas can be tagged by detecting the emitted Cherenkov light, which is not produced by α\alphas. In this paper we confirm this possibility. For the first time we measured the Cherenkov light emitted by a CUORE crystal, and found it to be 100 eV at the QQ-value of the decay. To completely reject the α\alpha background, we compute that one needs light detectors with baseline noise below 20 eV RMS, a value which is 3-4 times smaller than the average noise of the bolometric light detectors we are using. We point out that an improved light detector technology must be developed to obtain TeO2_2 bolometric experiments able to probe the inverted hierarchy of neutrino masses.Comment: 5 pages, 4 figures. Added referee correction

    Linkages between sanitation and the Sustainable Development Goals: a case study of Brazil

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    This paper identifies opportunities from targeted and integrated sanitation action to achieve the Sustainable Development Goals (SDGs). This is contextualised to the case of Brazil through a systematic approach applied to the sanitation sector that considers the range of infrastructure, management services and people involved in different phases of the service chain, from municipal wastewater containment to safe disposal or re‐use. Articulating the social, economic and environmental dimensions of sanitation, this study analyses their links with each of the 169 SDG targets. We demonstrate that 87 targets across 16 goals require action in Brazil's sanitation sector to achieve the SDGs. Furthermore, we identify synergies between sanitation and 124 targets in four domains: basic services for resilience building, equity and empowerment, pollution reduction and waste reuse and economic well‐being. Key results include the need for Brazil to invest in closed‐loop systems that valorise waste as a resource and the need to multiply efforts in the integrated provision of basic services in low‐income areas most affected by the lack of access to adequate sanitation. The links identified are supported by the compiled evidence of published research. The analysis of linkages through this structured approach aims to highlight opportunities for strategic governance action to support policy harmonisation and partnerships across Brazil's sanitation sector and beyond. With this research, we show that establishing linkages among the SDGs provides an adaptable framework that can support policy‐makers and practitioners seeking to deliver on the 2030 Agenda

    New experimental limits on the alpha decays of lead isotopes

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    For the first time a PbWO4 crystal was grown using ancient Roman lead and it was run as a cryogenic detector. Thanks to the simultaneous and independent read-out of heat and scintillation light, the detector was able to discriminate beta/gamma interactions with respect to alpha particles down to low energies. New more stringent limits on the alpha decays of the lead isotopes are presented. In particular a limit of T_{1/2} > 1.4*10^20 y at a 90% C.L. was evaluated for the alpha decay of 204Pb to 200Hg

    New application of superconductors: high sensitivity cryogenic light detectors

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    In this paper we describe the current status of the CALDER project, which is developing ultra-sensitive light detectors based on superconductors for cryogenic applications. When we apply an AC current to a superconductor, the Cooper pairs oscillate and acquire kinetic inductance, that can be measured by inserting the superconductor in a LC circuit with high merit factor. Interactions in the superconductor can break the Cooper pairs, causing sizable variations in the kinetic inductance and, thus, in the response of the LC circuit. The continuous monitoring of the amplitude and frequency modulation allows to reconstruct the incident energy with excellent sensitivity. This concept is at the basis of Kinetic Inductance Detectors (KIDs), that are characterized by natural aptitude to multiplexed read-out (several sensors can be tuned to different resonant frequencies and coupled to the same line), resolution of few eV, stable behavior over a wide temperature range, and ease in fabrication. We present the results obtained by the CALDER collaboration with 2x2 cm2 substrates sampled by 1 or 4 Aluminum KIDs. We show that the performances of the first prototypes are already competitive with those of other commonly used light detectors, and we discuss the strategies for a further improvement

    Characterization of the KID-Based Light Detectors of CALDER

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    The aim of the Cryogenic wide-Area Light Detectors with Excellent Resolution (CALDER) project is the development of light detectors with active area of 5×55\times5 cm2^2 and noise energy resolution smaller than 20 eV RMS, implementing phonon-mediated kinetic inductance detectors. The detectors are developed to improve the background suppression in large-mass bolometric experiments such as CUORE, via the double read-out of the light and the heat released by particles interacting in the bolometers. In this work, we present the characterization of the first light detectors developed by CALDER. We describe the analysis tools to evaluate the resonator parameters (resonant frequency and quality factors) taking into account simultaneously all the resonance distortions introduced by the read-out chain (as the feed-line impedance and its mismatch) and by the power stored in the resonator itself. We detail the method for the selection of the optimal point for the detector operation (maximizing the signal-to-noise ratio). Finally, we present the response of the detector to optical pulses in the energy range of 0-30 keV
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