696 research outputs found

    High‐Speed Deterministic‐Latency Serial IO

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    In digital systems, serial IO at speeds in the range from 1 to 20 Gbps is realized by means of dedicated transceivers, named serializer-deserializers (SerDeses). In general, due to their internal architecture, the data transfer delay, or the latency, may vary after a reset of the device. On the other hand, some applications, such as high-speed transfer protocols for analog-to-digital and digital-to-analog converters, trigger and data acquisition systems, clock distribution, synchronization and control of radio equipment need this delay to be constant at each reset. In this chapter, we focus on a serial IO architecture based on configurable transceivers embedded in field-programmable gate arrays (FPGAs). We will show how it is possible to achieve deterministic-latency operation in a line-code-independent way. As a case study, we will consider a synchronous 2.5-Gbps serial link based on an 8b10b line code

    Emulating the GLink Chip-Set with FPGA Serial Transceivers in the ATLAS Level-1 Muon Trigger

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    Many High Energy Physics experiments based their serial links on the Agilent HDMP-1032/34A serializer/deserializer chip-set (or GLink). This success was mainly due to the fact that this pair of chips was able to transfer data at \sim 1 Gb/s with a deterministic latency, fixed after each power up or reset of the link. Despite this unique timing feature, Agilent discontinued the production and no compatible commercial off-the-shelf chip-sets are available. The ATLAS Level-1 Muon trigger includes some serial links based on GLink in order to transfer data from the detector to the counting room. The transmission side of the links will not be upgraded, however a replacement for the receivers in the counting room in case of failures is needed. In this paper, we present a solution to replace GLink transmitters and receivers. Our design is based on the gigabit serial IO (GTP) embedded in a Xilinx Virtex 5 Field Programmable Gate Array (FPGA). We present the architecture and we discuss parameters of the implementation such as latency and resource occupation. We compare the GLink chip-set and the GTP-based emulator in terms of latency, eye diagram and power dissipation

    Radiation Damage in Polyethylene Naphthalate Thin-Film Scintillators.

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    This paper describes the scintillation features and the radiation damage in polyethylene naphthalate 100 µm-thick scintillators irradiated with an 11 MeV proton beam and with a 1 MeV electron beam at doses up to 15 and 85 Mrad, respectively. The scintillator emission spectrum, optical transmission, light yield loss, and scintillation pulse decay times were investigated before and after the irradiation. A deep blue emission spectrum peaked at 422 nm, and fast and slow scintillation decay time constants of the order of 1-2 ns and 25-30 nm, respectively, were measured. After irradiation, transmittance showed a loss of transparency for wavelengths between 380 and 420 nm, and a light yield reduction of ~40% was measured at the maximum dose of 85 Mrad

    Definition of the Immune Parameters Related to COVID-19 Severity

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    A relevant portion of patients with disease caused by the severe acute respiratory syndrome coronavirus 2 (COVID-19) experience negative outcome, and several laboratory tests have been proposed to predict disease severity. Among others, dramatic changes in peripheral blood cells have been described. We developed and validated a laboratory score solely based on blood cell parameters to predict survival in hospitalized COVID-19 patients. We retrospectively analyzed 1,619 blood cell count from 226 consecutively hospitalized COVID-19 patients to select parameters for inclusion in a laboratory score predicting severity of disease and survival. The score was derived from lymphocyte- and granulocyte-associated parameters and validated on a separate cohort of 140 consecutive COVID-19 patients. Using ROC curve analysis, a best cutoff for score of 30.6 was derived, which was associated to an overall 82.0% sensitivity (95% CI: 78–84) and 82.5% specificity (95% CI: 80–84) for detecting outcome. The scoring trend effectively separated survivor and non-survivor groups, starting 2 weeks before the end of the hospitalization period. Patients’ score time points were also classified into mild, moderate, severe, and critical according to the symptomatic oxygen therapy administered. Fluctuations of the score should be recorded to highlight a favorable or unfortunate trend of the disease. The predictive score was found to reflect and anticipate the disease gravity, defined by the type of the oxygen support used, giving a proof of its clinical relevance. It offers a fast and reliable tool for supporting clinical decisions and, most important, triage in terms of not only prioritization but also allocation of limited medical resources, especially in the period when therapies are still symptomatic and many are under development. In fact, a prolonged and progressive increase of the score can suggest impaired chances of survival and/or an urgent need for intensive care unit admission

    Standalone vertex finding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

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    A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction
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