60,295 research outputs found

    The BaBar Electromagnetic Calorimeter: Status and Performance Improvements

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    The electromagnetic calorimeter at the BaBar detector, part of the asymmetric B Factory at SLAC, measures photons in the energy range from 20 MeV to 8 GeV with high resolution. The current status of the calorimeter, now in its seventh year of operation, is being presented, as well as details on improvements made to the analysis code during the last years.Comment: 6 pages, 15 figures, presented at the 2005 IEEE Nuclear Science Symposium and submitted to the Conference Proceedings of the 2005 IEEE Nuclear Science Symposiu

    Technical Design Report for PANDA Electromagnetic Calorimeter (EMC)

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    This document presents the technical layout and the envisaged performance of the Electromagnetic Calorimeter (EMC) for the PANDA target spectrometer. The EMC has been designed to meet the physics goals of the PANDA experiment. The performance figures are based on extensive prototype tests and radiation hardness studies. The document shows that the EMC is ready for construction up to the front-end electronics interface

    Recent Results from the RICE Experiment at the South Pole

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    We present a compilation of recent results, submitted to the 2003 International Cosmic Ray Conference (Tsukuba, Japan). These include: a) Revised Monte Carlo estimates of the radiofrequency signals produced by electromagnetic showers in ice, b) an updated search for ultra-high energy (UHE) neutrinos based on detection of radio-wavelength Cherenkov radiation; such radiation results from neutrino-induced electromagnetic showers in cold Polar ice, and c) An in situ measurement of the index of refraction through the South Polar firn.Comment: Compendium of RICE collaboration submissions to ICRC0

    The International Linear Collider

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    In this article, we describe the key features of the recently completed technical design for the International Linear Collider (ILC), a 200-500 GeV linear electron-positron collider (expandable to 1 TeV) that is based on 1.3 GHz superconducting radio-frequency (SCRF) technology. The machine parameters and detector characteristics have been chosen to complement the Large Hadron Collider physics, including the discovery of the Higgs boson, and to further exploit this new particle physics energy frontier with a precision instrument. The linear collider design is the result of nearly twenty years of R&D, resulting in a mature conceptual design for the ILC project that reflects an international consensus. We summarize the physics goals and capability of the ILC, the enabling R&D and resulting accelerator design, as well as the concepts for two complementary detectors. The ILC is technically ready to be proposed and built as a next generation lepton collider, perhaps to be built in stages beginning as a Higgs factory.Comment: 41 page

    Ultrahigh Energy Cosmic Rays

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    This is a review of the most resent results from the investigation of the Ultrahigh Energy Cosmic Rays, particles of energy exceeding 1018^{18} eV. After a general introduction to the topic and a brief review of the lower energy cosmic rays and the detection methods, the two most recent experiments, the High Resolution Fly's Eye (HiRes) and the Southern Auger Observatory are described. We then concentrate on the results from these two experiments on the cosmic ray energy spectrum, the chemical composition of these cosmic rays and on the searches for their sources. We conclude with a brief analysis of the controversies in these results and the projects in development and construction that can help solve the remaining problems with these particles.Comment: 40 pages, 27 figure

    Cosmic-Ray Events as Background in Imaging Atmospheric Cherenkov Telescopes

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    The dominant background for observations of gamma-rays in the energy region above 50 GeV with Imaging Atmospheric Cherenkov telescopes are cosmic-ray events. The images of most of the cosmic ray showers look significantly different from those of gamma-rays and are therefore easily discriminated. However, a small fraction of events seems to be indistinguishable from gamma-rays. This constitutes an irreducible background to the observation of high-energy gamma-ray sources, and limits the sensitivity achievable with a given instrument. Here, a Monte Carlo study of gamma-like cosmic-ray events is presented. The nature of gamma-like cosmic-ray events, the shower particles that are responsible for the gamma-like appearance, and the dependence of these results on the choice of the hadronic interaction model are investigated. Most of the gamma-like cosmic ray events are characterised by the production of high-energy pi0's early in the shower development which dump most of the shower energy into electromagnetic sub-showers. Also Cherenkov light from single muons can mimic gamma-rays in close-by pairs of telescopes. Differences of up to 25% in the collection area for gamma-like proton showers between QGSJet/FLUKA and Sibyll/FLUKA simulations have been found.Comment: Accepted by Journal of Astroparticle Physic

    Numerical and Theoretical Studies of Radiation from Plasma Dipole and its Applications

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    Department of PhysicsThe localized plasma dipole oscillation technique was first proposed by Kwon K. et al in 2016 as an efficient terahertz radiation source [1]. This can be achieved by cross-shooting two-color ultrashort laser pulses into plasma and can be applied for diagnostic purposes as well. The ensemble of charged particles oscillating like plasma dipoles radiate EM waves at plasma frequency (??p) with the narrowband spectrum and carry meaningful information about the bulk plasma. In particular, by measuring the frequency of radiated signals, local plasma density at the focused point can be detected. Comparing the new idea with the conventionally utilized techniques such as interferometry, reflectometry, and Langmuir probes [2-4], we insist that our method has numerous advantages as a technique for measuring the density [5]. Theoretical estimations accompanied by 1D, 2D, and 3D PIC simulations indicated that embedded plasma dipole oscillators show complex behavior leading to harmonic generations and many nonlinear effects that require further investigation. In this thesis, the dipole formation, radiation scheme, and density reconstruction measurements are reported and the investigations about magnetic field effects and harmonic generations are introduced briefly.clos
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