1,143 research outputs found

    PMF the front end electronic for the ALFA detector

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    International audienceThe PMF (Photo Multiplier Front end) is the front end electronics designed for the ATLAS luminometer ALFA (Absolute Luminosity For ATLAS) made of 20 staggered U-V scintillating fiber layers inserted in Roman Pots (eight in total). Each of these plans is made of 64 fibers. The PMF consists of a 64 channels photomultiplier (MAPMT) and a very compact stack of three different PCBs (3x3 cm2), mounted directly on the back and in the shadow of the MAPMT: a board which brings the high voltage to the MAPMT, an intermediate board used to send the signals to connectors located on the edge and, finally, a board with the readout chip MAROC (Multi Anode Read Out Chip), directly bonded on the PCB, on one side and a FPGA on the other. The 64 inputs MAROC ASIC allows correcting for the gain spread of MAPMT channels thanks to a 6 bits variable gain preamplifier. For each channel the signal is shaped (fast shaper, 15ns) and discriminated to produce a trigger output. A multiplexed charge output is also produced both in analog and digital thanks to a Wilkinson ADC. The main requirements are the following: 100 % trigger efficiency for a signal greater than 1/3 of a photoelectron, a charge measurement up to 30 photoelectrons with a linearity of 2 % or better and a cross talk of 1 % or less. The performances of the second version of MAROC were checked successfully during the year 2007 at LAL-Orsay. A nice dispersion of the trigger output (± 5 fC) was, in particular, observed. A sample of PMFs was produced during autumn 2007 as a prototype. Laboratory tests were performed both at LAL and CERN respectively on the third PCB (the one with MAROC) and on a full PMF equipped with a MAPMT illuminated by a LED. They were carried out using dedicated test board and acquisition software and have allowed the approval of the design and the green light for the final production and integration with the detector. Beam tests of a complete Roman Pot, equipped with 23 PMFs, will take place during summer 2008 for two periods and will conclude the test phase and mark the beginning of the final production

    Hadron beam test of a scintillating fibre tracker system for elastic scattering and luminosity measurement in ATLAS

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    A scintillating fibre tracker is proposed to measure elastic proton scattering at very small angles in the ATLAS experiment at CERN. The tracker will be located in so-called Roman Pot units at a distance of 240 m on each side of the ATLAS interaction point. An initial validation of the design choices was achieved in a beam test at DESY in a relatively low energy electron beam and using slow off-the-shelf electronics. Here we report on the results from a second beam test experiment carried out at CERN, where new detector prototypes were tested in a high energy hadron beam, using the first version of the custom designed front-end electronics. The results show an adequate tracking performance under conditions which are similar to the situation at the LHC. In addition, the alignment method using so-called overlap detectors was studied and shown to have the expected precision.Comment: 12 pages, 8 figures. Submitted to Journal of Instrumentation (JINST

    Esophageal squamous cell carcinoma presenting with extensive skin lesions: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Esophageal squamous cell carcinoma (ESCC) is the most common histological subtype of cancer in the upper and middle esophagus and is characterized by a high rate of mortality. The incidence of esophageal cancer varies greatly among regions of the world and occurs at a high frequency in Asia and South America.</p> <p>Case presentation</p> <p>In our department, a 51-year-old man was diagnosed with ESCC after presenting with extensive disseminated skin nodules. Biopsy of the nodules showed metastatic ESCC. Cutaneous manifestations of esophageal neoplasia are very rare and are mainly described for esophageal adenocarcinoma (EADC). Here we report a very uncommon case of extensive skin metastases of ESCC.</p> <p>Conclusion</p> <p>Early biopsies of suspicious skin lesions are important and should be performed in patients with unclear symptoms such as weight loss or dysphagia and especially in patients with a history of cancer, since they can reveal the existence of a distant malignant disease leading to diagnosis and prompt therapy.</p

    The Vehicle, Spring 1993

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    Table of Contents The Shape of Things to Come.Peter F. Essigpage 6 SaxophoneWalt Howardpage 6 Gravity BedSue Songerpage 7 UntitledJennifer Gutowskipage 8 uncertaintyWalt Howardpage 9 Ruth Ann, et. al.Susan Eisenhourpage 9 Failed IndustryScott Langenpage 10 UntitledKaren Wisspage 10 wanted:Walt Howardpage 10 Dida; 1978Diana Matijaspage 11 UntitledJennifer Gutowskipage 12 The Lesson in NovemberSue Songerpage 13 Coal MinerJames P. Tangpage 16 Christmas CrueltySue Songerpage 17 Astral ProjectionSusan Eisenhourpage 18 UntitledBen Hausmannpage 19 Into Zagreb\u27s Evening*Diana Matjaspage 20 UntitledJennifer Gutowskipage 22 The AnniversaryJennifer Moropage 23 NudeDan Trutterpage 24 death for saleWalt Howardpage 24 JudgedKevin St. Angelpage 25 Nature\u27s RefugeeScott Langenpage 25 Arrowhead Hunting at TippecanoeJennifer Moropage 26 UntitledKimberly Foxpage 27 TAINTED LOVESarah C. Patiencepage 28 cemeteryWalt Howardpage 28 Cow GameSusan Eisenhourpage 29 UntitledJennifer Gutowskipage 31 ReflectionsPeter F. Essigpage 32 Destination U.S.A.Dan Trutterpage 33 UntitledMario Letopage 33 Authors\u27 Pagepage 34https://thekeep.eiu.edu/vehicle/1061/thumbnail.jp

    The Vehicle, Spring 1993

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    Table of Contents The Shape of Things to Come.Peter F. Essigpage 6 SaxophoneWalt Howardpage 6 Gravity BedSue Songerpage 7 UntitledJennifer Gutowskipage 8 uncertaintyWalt Howardpage 9 Ruth Ann, et. al.Susan Eisenhourpage 9 Failed IndustryScott Langenpage 10 UntitledKaren Wisspage 10 wanted:Walt Howardpage 10 Dida; 1978Diana Matijaspage 11 UntitledJennifer Gutowskipage 12 The Lesson in NovemberSue Songerpage 13 Coal MinerJames P. Tangpage 16 Christmas CrueltySue Songerpage 17 Astral ProjectionSusan Eisenhourpage 18 UntitledBen Hausmannpage 19 Into Zagreb\u27s Evening*Diana Matjaspage 20 UntitledJennifer Gutowskipage 22 The AnniversaryJennifer Moropage 23 NudeDan Trutterpage 24 death for saleWalt Howardpage 24 JudgedKevin St. Angelpage 25 Nature\u27s RefugeeScott Langenpage 25 Arrowhead Hunting at TippecanoeJennifer Moropage 26 UntitledKimberly Foxpage 27 TAINTED LOVESarah C. Patiencepage 28 cemeteryWalt Howardpage 28 Cow GameSusan Eisenhourpage 29 UntitledJennifer Gutowskipage 31 ReflectionsPeter F. Essigpage 32 Destination U.S.A.Dan Trutterpage 33 UntitledMario Letopage 33 Authors\u27 Pagepage 34https://thekeep.eiu.edu/vehicle/1061/thumbnail.jp

    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

    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

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon μ\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, μμ\mu\mu or eμe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

    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

    Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

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    A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN
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