523 research outputs found

    Smart CMOS image sensor for lightning detection and imaging

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    We present a CMOS image sensor dedicated to lightning detection and imaging. The detector has been designed to evaluate the potentiality of an on-chip lightning detection solution based on a smart sensor. This evaluation is performed in the frame of the predevelopment phase of the lightning detector that will be implemented in the Meteosat Third Generation Imager satellite for the European Space Agency. The lightning detection process is performed by a smart detector combining an in-pixel frame-to-frame difference comparison with an adjustable threshold and on-chip digital processing allowing an efficient localization of a faint lightning pulse on the entire large format array at a frequency of 1 kHz. A CMOS prototype sensor with a 256×256 pixel array and a 60 μm pixel pitch has been fabricated using a 0.35 μm 2P 5M technology and tested to validate the selected detection approach

    In-flight calibration and verification of the Planck-LFI instrument

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    In this paper we discuss the Planck-LFI in-flight calibration campaign. After a brief overview of the ground test campaigns, we describe in detail the calibration and performance verification (CPV) phase, carried out in space during and just after the cool-down of LFI. We discuss in detail the functionality verification, the tuning of the front-end and warm electronics, the preliminary performance assessment and the thermal susceptibility tests. The logic, sequence, goals and results of the in-flight tests are discussed. All the calibration activities were successfully carried out and the instrument response was comparable to the one observed on ground. For some channels the in-flight tuning activity allowed us to improve significantly the noise performance.Comment: Long technical paper on Planck LFI in flight calibration campaign: 109 pages in this (not final) version, 100 page in the final JINST versio

    CMOS Image Sensor with on-chip Intelligence for Lightning Detection and Imaging

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    We present A CMOS image sensor dedicated to lightning detection and imaging. The detector has been designed for the pre-development phase of the lightning detector that will be implemented in Meteosat Third Generation Imager (MTG-I) satellite for European Space Agency (ESA). The lightning detection process (Patent applied) is performed by a smart detector combining on in-pixel frame to frame difference comparison with an adjustable threshold and onchip digital processing allowing an efficient localization of faint lightning pulse on the entire large format array at 1 kHz. A CMOS prototype sensor with a 256x256 pixel array and 60μm pixel pitch has been fabricated using a 0.35μm 2P 5M technology and tested to validate the selected detection approach. OCIS codes: (040.6070 ) Solid state detectors; (250.3140) Integrated optoelectronic circuits; (280.4788) Optical sensing and sensors; (110.2970) Image detection systems

    Subcutaneous anti-COVID-19 hyperimmune immunoglobulin for prevention of disease in asymptomatic individuals with SARS-CoV-2 infection: a double-blind, placebo-controlled, randomised clinical trialResearch in context

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    Summary: Background: Anti-COVID-19 hyperimmune immunoglobulin (hIG) can provide standardized and controlled antibody content. Data from controlled clinical trials using hIG for the prevention or treatment of COVID-19 outpatients have not been reported. We assessed the safety and efficacy of subcutaneous anti-COVID-19 hyperimmune immunoglobulin 20% (C19-IG20%) compared to placebo in preventing development of symptomatic COVID-19 in asymptomatic individuals with SARS-CoV-2 infection. Methods: We did a multicentre, randomized, double-blind, placebo-controlled trial, in asymptomatic unvaccinated adults (≥18 years of age) with confirmed SARS-CoV-2 infection within 5 days between April 28 and December 27, 2021. Participants were randomly assigned (1:1:1) to receive a blinded subcutaneous infusion of 10 mL with 1 g or 2 g of C19-IG20%, or an equivalent volume of saline as placebo. The primary endpoint was the proportion of participants who remained asymptomatic through day 14 after infusion. Secondary endpoints included the proportion of individuals who required oxygen supplementation, any medically attended visit, hospitalisation, or ICU, and viral load reduction and viral clearance in nasopharyngeal swabs. Safety was assessed as the proportion of patients with adverse events. The trial was terminated early due to a lack of potential benefit in the target population in a planned interim analysis conducted in December 2021. ClinicalTrials.gov registry: NCT04847141. Findings: 461 individuals (mean age 39.6 years [SD 12.8]) were randomized and received the intervention within a mean of 3.1 (SD 1.27) days from a positive SARS-CoV-2 test. In the prespecified modified intention-to-treat analysis that included only participants who received a subcutaneous infusion, the primary outcome occurred in 59.9% (91/152) of participants receiving 1 g C19-IG20%, 64.7% (99/153) receiving 2 g, and 63.5% (99/156) receiving placebo (difference in proportions 1 g C19-IG20% vs. placebo, −3.6%; 95% CI -14.6% to 7.3%, p = 0.53; 2 g C19-IG20% vs placebo, 1.1%; −9.6% to 11.9%, p = 0.85). None of the secondary clinical efficacy endpoints or virological endpoints were significantly different between study groups. Adverse event rate was similar between groups, and no severe or life-threatening adverse events related to investigational product infusion were reported. Interpretation: Our findings suggested that administration of subcutaneous human hyperimmune immunoglobulin C19-IG20% to asymptomatic individuals with SARS-CoV-2 infection was safe but did not prevent development of symptomatic COVID-19. Funding: Grifols

    Multiplicity and transverse momentum dependence of charge-balance functions in pPb and PbPb collisions at LHC energies

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    International audienceMeasurements of the charge-dependent two-particle angular correlation function in proton-lead (pPb) collisions at a nucleon-nucleon center-of-mass energy of sNN\sqrt{s_\mathrm{NN}} = 8.16 TeV and lead-lead (PbPb) collisions atsNN\sqrt{s_\mathrm{NN}} = 5.02 TeV are reported. The pPb and PbPb datasets correspond to integrated luminosities of 186\nbinv and 0.607 nb1^{-1}, respectively, and were collected using the CMS detector at the CERN LHC. The charge-dependent correlations are characterized by balance functions of same- and opposite-sign particle pairs. The balance functions, which contain information about the creation time of charged particle pairs and the development of collectivity, are studied as functions of relative pseudorapidity (Δη\Delta \eta) and relative azimuthal angle (Δϕ\Delta \phi), for various multiplicity and transverse momentum (pTp_\mathrm{T}) intervals. A multiplicity dependence of the balance function is observed in Δη\Delta \eta and Δϕ\Delta \phi for both systems. The width of the balance functions decreases towards high-multiplicity collisions in the momentum region <\lt2 GeV, for pPb and PbPb results. No multiplicity dependence is observed at higher transverse momentum. The data are compared with HYDJET, HIJING and AMPT generator predictions, none of which capture completely the multiplicity dependence seen in the data

    Luminosity determination using Z boson production at the CMS experiment

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    International audienceThe measurement of Z boson production is presented as a method to determine the integrated luminosity of CMS data sets. The analysis uses proton-proton collision data, recorded by the CMS experiment at the CERN LHC in 2017 at a center-of-mass energy of 13 TeV. Events with Z bosons decaying into a pair of muons are selected. The total number of Z bosons produced in a fiducial volume is determined, together with the identification efficiencies and correlations from the same dataset, in small intervals of 2 pb1^{-1} of integrated luminosity, thus facilitating the efficiency and rate measurement as a function of time and instantaneous luminosity. Using the ratio of the efficiency-corrected numbers of Z bosons, the precisely measured integrated luminosity of one data set is used to determine the luminosity of another. For the first time, a full quantitative uncertainty analysis of the use of Z bosons for the integrated luminosity measurement is performed. The uncertainty in the extrapolation between two data sets, recorded in 2017 at low and high instantaneous luminosity, is less than 0.5%. We show that the Z boson rate measurement constitutes a precise method, complementary to traditional methods, with the potential to improve the measurement of the integrated luminosity

    Probing small Bjorken-xx nuclear gluonic structure via coherent J/ψ\psi photoproduction in ultraperipheral PbPb collisions at sNN\sqrt{s_\mathrm{NN}} = 5.02 TeV

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    International audienceQuasi-real photons exchanged in relativistic heavy ion interactions are powerful probes of the gluonic structure of nuclei. The first measurement of the coherent J/ψ\psi photoproduction cross section in ultraperipheral lead-lead collisions is presented over a wide range of photon-nucleus center-of-mass energies per nucleon (WγNPb^\text{Pb}_{\gamma\text{N}}). Results are obtained using data at the nucleon-nucleon center-of-mass energy of 5.02 TeV collected by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 1.52 nb1^{-1}. The cross section is observed to rise rapidly at low WγNPb^\text{Pb}_{\gamma\text{N}}, and plateau above WγNPb^\text{Pb}_{\gamma\text{N}}\approx 40 GeV, up to 400 GeV, a new regime of small Bjorken-xx (\approx 6 ×\times 105^{-5}) gluons being probed in a heavy nucleus. The observed energy dependence is not predicted by current quantum chromodynamic models

    Search for inelastic dark matter in events with two displaced muons and missing transverse momentum in proton-proton collisions at s\sqrt{s} = 13 TeV

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    International audienceA search for dark matter in events with a displaced muon pair and missing transverse momentum is presented. The analysis is performed using an integrated luminosity of 138 fb1^{-1} of proton-proton (pp) collision data at a center-of-mass energy of 13 TeV produced by the LHC in 2016-2018. No significant excess over the predicted backgrounds is observed. Upper limits are set on the product of the inelastic dark matter production cross section σ\sigma(pp \to A' \toχ1\chi_1χ2\chi_2) and the decay branching fraction B\mathcal{B}(χ2\chi_2\toχ1μ+μ\chi_1\mu^+\mu^-), where A' is a dark photon and χ1\chi_1 and χ2\chi_2 are dark matter states with near mass degeneracy. This is the first dedicated collider search for inelastic dark matter

    Search for stealth supersymmetry in final states with two photons, jets, and low missing transverse momentum in proton-proton collisions at s\sqrt{s} = 13 TeV

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    International audienceThe results of a search for stealth supersymmetry in final states with two photons and jets, targeting a phase space region with low missing transverse momentum (pTmissp_\text{T}^\text{miss}), are reported. The study is based on a sample of proton-proton collisions at s\sqrt{s} =13 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb1^{-1}. As LHC results continue to constrain the parameter space of the minimal supersymmetric standard model, the low pTmissp_\text{T}^\text{miss} regime is increasingly valuable to explore. To estimate the backgrounds due to standard model processes in such events, we apply corrections derived from simulation to an estimate based on a control selection in data. The results are interpreted in the context of simplified stealth supersymmetry models with gluino and squark pair production. The observed data are consistent with the standard model predictions, and gluino (squark) masses of up to 2150 (1850) GeV are excluded at the 95% confidence level
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