190 research outputs found

    Eco-friendly gas mixtures for Resistive Plate Chambers based on Tetrafluoropropene and Helium

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    Due to the recent restrictions deriving from the application of the Kyoto protocol, the main components of the gas mixtures presently used in the Resistive Plate Chambers systems of the LHC experiments will be most probably phased out of production in the coming years. Identifying possible replacements with the adequate characteristics requires an intense R&D, which was recently started, also in collaborations across the various experiments. Possible candidates have been proposed and are thoroughly investigated. Some tests on one of the most promising candidate - HFO-1234ze, an allotropic form of tetrafluoropropane- have already been reported. Here an innovative approach, based on the use of Helium, to solve the problems related to the too elevate operating voltage of HFO-1234ze based gas mixtures, is discussed and the relative first results are shown.Comment: 9 pages, 6 figures, 1 tabl

    An analysis of materials used in the RPC detector and in the closed loop gas system of CMS at the LHC.

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    The results are reported of the study of materials used in the CERN Closed Loop recirculation gas system currently under test with the RPC muon detectors in the CMS experiment at the LHC. Studies include a sampling campaign in a low-radiation environment (cosmic rays at the CERN ISR test site). We describe the dedicated RPC chamber tests, the chemical analysis of the filters and gas used, and discuss the results of the Closed Loop system

    Carnosol Attenuates LPS-Induced Inflammation of Cardiomyoblasts by Inhibiting NF-ÎşB: A Mechanistic in Vitro and in Silico Study

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    Carnosol possesses several beneficial pharmacological properties. However, its role in lipopolysaccharide (LPS) induced inflammation and cardiomyocyte cell line (H9C2) has never been investigated. Therefore, the effect of carnosol and an NF-kappa B inhibitor BAY 11-7082 was examined, and the underlying role of the NF-kappa B-dependent inflammatory pathway was analyzed as the target enzyme. Cell viability, inflammatory cytokines levels (tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 beta, IL-6, and prostaglandin E-2 (PGE(2))), and related gene expression (TNF-alpha, IL-1 beta, IL-6, and cyclooxygenase-2 (COX-2)) were analyzed by ELISA and real-time PCR. In addition, docking studies analyzed carnosol's molecular interactions and binding modes to NF-kappa B and IKK. We report that LPS caused the reduction of cell viability while enhancing both cytokines protein and mRNA levels (P < 0.001, for all cases). However, the BAY 11-7082 pretreatment of the cells and carnosol increased cell viability and reduced cytokine protein and mRNA levels (P < 0.001 vs. LPS, for all cases). Furthermore, our in silico analyses also supported the modulation of NF-kappa B and IKK by carnosol. This evidence highlights the defensive effects of carnosol against sepsis-induced myocardial dysfunction and, contextually, paved the rationale for the next in vitro and in vivo studies aimed to precisely describe its mechanism(s) of action

    Construction and Performance of Large-Area Triple-GEM Prototypes for Future Upgrades of the CMS Forward Muon System

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    At present, part of the forward RPC muon system of the CMS detector at the CERN LHC remains uninstrumented in the high-\eta region. An international collaboration is investigating the possibility of covering the 1.6 < |\eta| < 2.4 region of the muon endcaps with large-area triple-GEM detectors. Given their good spatial resolution, high rate capability, and radiation hardness, these micro-pattern gas detectors are an appealing option for simultaneously enhancing muon tracking and triggering capabilities in a future upgrade of the CMS detector. A general overview of this feasibility study will be presented. The design and construction of small (10\times10 cm2) and full-size trapezoidal (1\times0.5 m2) triple-GEM prototypes will be described. During detector assembly, different techniques for stretching the GEM foils were tested. Results from measurements with x-rays and from test beam campaigns at the CERN SPS will be shown for the small and large prototypes. Preliminary simulation studies on the expected muon reconstruction and trigger performances of this proposed upgraded muon system will be reported.Comment: 7 pages, 25 figures, submitted for publication in conference record of the 2011 IEEE Nuclear Science Symposium, Valencia, Spai

    Two- and Three-Dimensional Reconstruction and Analysis of the Straw Tubes Tomography in the Btev Experiment

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    A check of the eccentricity of the aluminised kapton straw tubes used in the BTeV experiment is accomplished using X-ray tomography of the section of tubes modules. 2 and 3-dimensional images of the single tubes and of the modules are reconstructed and analysed. Preliminary results show that a precision better than 40 ÎĽ\mum can be reached on the measurement of the straw radii.Comment: Presented by F.Massa at ICATPP05, Villa Olmo (Como) Italy, November 2005. 4 pages, 8 figures, uses lnfprep.st

    Characterization of GEM Detectors for Application in the CMS Muon Detection System

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    The muon detection system of the Compact Muon Solenoid experiment at the CERN Large Hadron Collider is based on different technologies for muon tracking and triggering. In particular, the muon system in the endcap disks of the detector consists of Resistive Plate Chambers for triggering and Cathode Strip Chambers for tracking. At present, the endcap muon system is only partially instrumented with the very forward detector region remaining uncovered. In view of a possible future extension of the muon endcap system, we report on a feasibility study on the use of Micro-Pattern Gas Detectors, in particular Gas Electron Multipliers, for both muon triggering and tracking. Results on the construction and characterization of small tripleGas Electron Multiplier prototype detectors are presented.Comment: 7 pages, 19 figures, submitted for publication in conference record of the 2010 IEEE Nuclear Science Symposium, Knoxville, T

    Overview of large area triple-GEM detectors for the CMS forward muon upgrade

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    In order to cope with the harsh environment expected from the high luminosity LHC, the CMS forward muon system requires an upgrade. The two main challenges expected in this environment are an increase in the trigger rate and increased background radiation leading to a potential degradation of the particle ID performance. Additionally, upgrades to other subdetectors of CMS allow for extended coverage for particle tracking, and adding muon system coverage to this region will further enhance the performance of CMS

    Design of a constant fraction discriminator for the VFAT3 front-end ASIC of the CMS GEM detector

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    In this work the design of a constant fraction discriminator (CFD) to be used in the VFAT3 chip for the read-out of the triple-GEM detectors of the CMS experiment, is described. A prototype chip containing 8 CFDs was implemented using 130 nm CMOS technology and test results are shown. © CERN 2016
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