2,705 research outputs found

    Resistive MSGC with double layered electrodes

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    The first successful attempts to optimize the electric field in Resistive Microstrip Gas Chamber (RMSGC) using additional field shaping strips located inside the detector substrate are described.Comment: Presented at 13th RD51 Collaboration meeting, CERN, Febr. 201

    Semi-transparent Boundary Conditions in the Worldline Formalism

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    The interaction of a quantum field with a background containing a Dirac delta function with support on a surface of codimension 1 represents a particular kind of matching conditions on that surface for the field. In this article we show that the worldline formalism can be applied to this model. We obtain the asymptotic expansion of the heat-kernel corresponding to a scalar field on Rd+1\mathbb{R}^{d+1} in the presence of an arbitrary regular potential and subject to this kind of matching conditions on a flat surface. We also consider two such surfaces and compute their Casimir attraction due to the vacuum fluctuations of a massive scalar field weakly coupled to the corresponding Dirac deltas.Comment: 12 page

    New crystals for Dual Readout calorimetry

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    Dual Readout Calorimetry is a promising new technique for highresolution calorimetry. It is based on simultaneous measurements, in the shower development process, of the scintillation and Cherenkov light (only produced by the electromagnetic shower component). In this way it is possible to measure, event by event, the contribution of the electromagnetic fraction, and to compensate for its fluctuations, that are the main source of degrading the hadronic energy resolution of calorimeters. In order to further improve both the electromagnetic and hadronic resolution, it is possible to reduce both the sampling fluctuations and the quantum fluctuations by using homogeneous, dense crystals. Promising results have been obtained by lead tungstate crystals (PbWO4), doped with small fractions of praseodymium or molybdenum. Results from the 2008 testbeam and perspective for the coming one this year will be shown

    Boundaries in the Moyal plane

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    We study the oscillations of a scalar field on a noncommutative disc implementing the boundary as the limit case of an interaction with an appropriately chosen confining background. The space of quantum fluctuations of the field is finite dimensional and displays the rotational and parity symmetry of the disc. We perform a numerical evaluation of the (finite) Casimir energy and obtain similar results as for the fuzzy sphere and torus.Comment: 19 pages, 6 figures. Replaced by published versio

    Fiber and crystals dual readout calorimeters

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    The RD52 (DREAM) collaboration is performing R&D on dual readout calorimetry techniques with the aim of improving hadronic energy resolution for future high energy physics experiments. The simultaneous detection of Cherenkov and scintillation light enables us to measure the electromagnetic fraction of hadron shower event-by-event. As a result, we could eliminate the main fluctuation which prevented from achieving precision energy measurement for hadrons. We have tested the performance of the lead and copper fiber prototypes calorimeters with various energies of electromagnetic particles and hadrons. During the beam test, we investigated the energy resolutions for electrons and pions as well as the identification of those particles in a longitudinally unsegmented calorimeter. Measurements were also performed on pure and doped PbWO4 crystals, as well as BGO and BSO, with the aim of realizing a crystal based dual readout detector. We will describe our results, focusing on the more promising properties of homogeneous media for the technique. Guidelines for additional developments on crystals will be also given. Finally we discuss the construction techniques that we have used to assemble our prototypes and give an overview of the ones that could be industrialized for the construction of a full hermetic calorimeter

    Casimir effect in Snyder Space

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    We show that two indistinguishable aspects of the divergences occurring in the Casimir effect, namely the divergence of the energy of the higher modes and the non-com\-pact\-ness of the momentum space, get disentangled in a given noncommutative setup. To this end, we consider a scalar field between two parallel plates in an anti-Snyder space. Additionally, the large mass decay in this noncommutative setup is not necessarily exponential.Comment: 15 pages, discussion regarding the large-mass asymptotics added, typos corrected, missing factor in eq. (1) correcte

    Demonstration of new possibilities of multilayer technology on resistive microstrip/ microdot detectors

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    The first successful attempts to optimize the electric field in Resistive Microstrip Gas Chamber and resistive microdot detectors using additional field shaping strips located inside the detector substrate are describedComment: Presented at the RD-51 mmini week, CERN, June 201
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