211 research outputs found

    First operation and drift field performance of a large area double phase LAr Electron Multiplier Time Projection Chamber with an immersed Greinacher high-voltage multiplier

    Full text link
    We have operated a liquid-argon large-electron-multiplier time-projection chamber (LAr LEM-TPC) with a large active area of 76 ×\times 40 cm2^2 and a drift length of 60 cm. This setup represents the largest chamber ever achieved with this novel detector concept. The chamber is equipped with an immersed built-in cryogenic Greinacher multi-stage high-voltage (HV) multiplier, which, when subjected to an external AC HV of \sim1 kVpp_{\mathrm{pp}}, statically charges up to a voltage a factor of \sim30 higher inside the LAr vessel, creating a uniform drift field of \sim0.5 kV/cm over the full drift length. This large LAr LEM-TPC was brought into successful operation in the double-phase (liquid-vapor) operation mode and tested during a period of \sim1 month, recording impressive three-dimensional images of very high-quality from cosmic particles traversing or interacting in the sensitive volume. The double phase readout and HV systems achieved stable operation in cryogenic conditions demonstrating their good characteristics, which particularly suit applications for next-generation giant-scale LAr-TPCs.Comment: 26 pages, 19 figure

    Inter-cluster reactivity of Metallo-aromatic and anti-aromatic Compounds and Their Applications in Molecular Electronics: A Theoretical Investigation

    Full text link
    Local reactivity descriptors such as the condensed local softness and Fukui function have been employed to investigate the inter-cluster reactivity of the metallo-aromatic (Al4Li- and Al4Na-) and anti-aromatic (Al4Li4 and Al4Na4) compounds. We use the concept of group softness and group Fukui function to study the strength of the nucleophilicity of the Al4 unit in these compounds. Our analysis shows that the trend of nucleophilicity of the Al4 unit in the above clusters is as follows; Al4Li- > Al4Na- > Al4Li4 > Al4Na 4 For the first time we have used the reactivity descriptors to show that these clusters can act as electron donating systems and thus can be used as a molecular cathode.Comment: 23 pages, 1 figure and 1 table of conten

    Performance Of A Liquid Argon Time Projection Chamber Exposed To The WANF Neutrino Beam

    Get PDF
    We present the results of the first exposure of a Liquid Argon TPC to a multi-GeV neutrino beam. The data have been collected with a 50 liters ICARUS-like chamber located between the CHORUS and NOMAD experiments at the CERN West Area Neutrino Facility (WANF). We discuss both the instrumental performance of the detector and its capability to identify and reconstruct low multiplicity neutrino interactions.Comment: 14 pages, 12 figures. Submitted for publication to Physical Review

    The LAGUNA design study- towards giant liquid based underground detectors for neutrino physics and astrophysics and proton decay searches

    Get PDF
    The feasibility of a next generation neutrino observatory in Europe is being considered within the LAGUNA design study. To accommodate giant neutrino detectors and shield them from cosmic rays, a new very large underground infrastructure is required. Seven potential candidate sites in different parts of Europe and at several distances from CERN are being studied: Boulby (UK), Canfranc (Spain), Fr\'ejus (France/Italy), Pyh\"asalmi (Finland), Polkowice-Sieroszowice (Poland), Slanic (Romania) and Umbria (Italy). The design study aims at the comprehensive and coordinated technical assessment of each site, at a coherent cost estimation, and at a prioritization of the sites within the summer 2010.Comment: 5 pages, contribution to the Workshop "European Strategy for Future Neutrino Physics", CERN, Oct. 200

    Measurement of Muon Neutrino Quasi-Elastic Scattering on Carbon

    Full text link
    The observation of neutrino oscillations is clear evidence for physics beyond the standard model. To make precise measurements of this phenomenon, neutrino oscillation experiments, including MiniBooNE, require an accurate description of neutrino charged current quasi-elastic (CCQE) cross sections to predict signal samples. Using a high-statistics sample of muon neutrino CCQE events, MiniBooNE finds that a simple Fermi gas model, with appropriate adjustments, accurately characterizes the CCQE events observed in a carbon-based detector. The extracted parameters include an effective axial mass, M_A^eff = 1.23+/-0.20 GeV, that describes the four-momentum dependence of the axial-vector form factor of the nucleon; and a Pauli-suppression parameter, kappa = 1.019+/-0.011. Such a modified Fermi gas model may also be used by future accelerator-based experiments measuring neutrino oscillations on nuclear targets.Comment: 5 pages, 3 figure

    Bright nanoparticles for an even brighter future: efficient production of luminescent carbon nanodots from olive mill wastewater

    Get PDF
    Este trabalho foi financiado pelo Concurso Anual para Projetos de Investigação, Desenvolvimento, Inovação e Criação Artística (IDI&CA) 2016 do Instituto Politécnico de Lisboa. Código de referência IPL/2016/NANOLIVE/ISELCarbon nanodots (CNDs) are a very recent class of spherical-shaped nanosized carbon materials possessing average typical diameters < 10 nm. Since the very first reports on carbon dots,1,2 a variety of methods (top-down and bottom-up strategies), carbon sources and passivating agents, have dealt with their synthesis.3 The bottom-up approach, encompassing the use of pyrolytic/solvothermal processes, is more amenable for large-scale production and can cope with a large diversity of carbon precursors, either from natural or synthetic sources, typically endowed with acid, alcohol and amine functionalities.4 Some of the interesting CNDs properties include tunable photoluminescence, outstanding photostability and negligible cytotoxicity. These unique properties have prompted their intense and widespread use in several fields, such as fluorescent bioimaging and nanomedicine, chemo/biosensing, photocatalysis and optoelectronics.4info:eu-repo/semantics/publishedVersio

    Measurement of the \nu_\mu charged current \pi^+ to quasi-elastic cross section ratio on mineral oil in a 0.8 GeV neutrino beam

    Get PDF
    Using high statistics samples of charged current νμ\nu_\mu interactions, MiniBooNE reports a measurement of the single charged pion production to quasi-elastic cross section ratio on mineral oil (CH2_2), both with and without corrections for hadron re-interactions in the target nucleus. The result is provided as a function of neutrino energy in the range 0.4 GeV <Eν<< E_\nu < 2.4 GeV with 11% precision in the region of highest statistics. The results are consistent with previous measurements and the prediction from historical neutrino calculations.Comment: 4 pages, 2 figure
    corecore