117 research outputs found

    Lycoris -- a large-area, high resolution beam telescope

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    A high-resolution beam telescope is one of the most important and demanding infrastructure components at any test beam facility. Its main purpose is to provide reference particle tracks from the incoming test beam particles to the test beam users, which allows measurement of the performance of the device-under-test (DUT). \LYCORIS, a six-plane compact beam telescope with an active area of \sim10×\times\SI{10}{\square\centi\metre} (extensible to 10×\times\SI{20}{\square\centi\metre}) was installed at the \DIITBF in 2019, to provide a precise momentum measurement in a \SI{1}{\tesla} solenoid magnet or to provide tracking over a large area. The overall design of \LYCORIS will be described as well as the performance of the chosen silicon sensor. The \SI{25}{\micro\metre} pitch micro-strip sensor used for \LYCORIS was originally designed for the \SID detector concept for the International Linear Collider. It adopts a second metallization layer to route signals from strips to the bump-bonded \KPIX ASIC and uses a wire-bonded flex cable for the connection to the DAQ and the power supply system. This arrangement eliminates the need for a dedicated hybrid PCB. Its performance was tested for the first time in this project. The system has been evaluated at the \DIITBF in several test-beam campaigns and has demonstrated an average single-point resolution of \SI{7.07}{\micro\meter}.Comment: 43 pages, 37 figure

    A Time Projection Chamber with GEM-Based Readout

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    For the International Large Detector concept at the planned International Linear Collider, the use of time projection chambers (TPC) with micro-pattern gas detector readout as the main tracking detector is investigated. In this paper, results from a prototype TPC, placed in a 1 T solenoidal field and read out with three independent GEM-based readout modules, are reported. The TPC was exposed to a 6 GeV electron beam at the DESY II synchrotron. The efficiency for reconstructing hits, the measurement of the drift velocity, the space point resolution and the control of field inhomogeneities are presented.Comment: 22 pages, 19 figure

    Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at s=8TeV\sqrt{s}=8\,\mathrm TeV{} with the ATLAS detector

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    ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider

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    Measurement of the Differential Production Cross Section of W Bosons and Charge Asymmetry at �s = 7 TeV with the ATLAS Detector

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    This document presents a measurement of the production cross section of W bosons and of its charge asymmetry in proton-proton collisions at a centre of mass energy of 7 TeV with the ATLAS detector. These measurements provide information on the momentum fraction of the protons carried by the partons contributing to the W production and therefore allow to better understand the parton distribution functions of the proton. The W candidate events are selected in the W�enu decay mode. The LAr electromagnetic calorimeter plays an important role in the detection of electrons and the author has worked on the on-line energy reconstruction in the LAr detectors. A subject which is treated in some detail is the evaluation of the charge misidentification rates for electrons and positrons. This is a key ingredient for charge related measurements such as the W charge asymmetry. In this document, the W production cross section times the branching ratio is studied inclusively, as a function of the lepton pseudorapidity and as a double differential measurement as a function of the lepton pseudorapidity and transverse energy. The charge asymmetry measurement is presented as a function of the lepton pseudorapidity and as a double differential measurement as well. The data were recorded by the ATLAS detector in 2011 and correspond to 4.7 fb�1

    Studies on Gas Electron Multiplier (GEM) modules for a Large Prototype TPC for the ILC

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    The International Large Detector is a detector concept for the ILC which uses a Time Projection Chamber as its the main tracker. Within the framework of the LCTPC collaboration, a Large Prototype (LP) TPC has been built as a demonstrator. Its endplate is able to contain up to seven identical modules of Micro-Pattern Gas Detectors (MPGD). The LP has been equipped with MPGD modules and studied with an electron beam (1-6 GeV) in a 1 Tesla magnetic field.The interest of this talk lies in the studies of the GridGEM (Gas Electron Multiplier) modules. Recent results on drift velocity, field distortions, spatial resolution and alignment measurements are presented as well as the current status and future plans of the R&D for the next module iteration. In addition, insight into the requirements and developments of an external Silicon tracker to accompany the LPTPC is given
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