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Lecrevisse T.,Institute Of Recherche Sur Les Lois Fondamentales Of Lunivers | Iwasa Y.,Massachusetts Institute of Technology
IEEE Transactions on Applied Superconductivity

In this paper, we report preliminary experimental results on protection study of two REBCO pancake coils based on the metal-as-insulation (MI) winding technique, a variant of the no-insulation (NI) winding technique, in which a metallic tape is cowound. Against the more-proven NI technique, our results demonstrate that the MI technique, too, is quite viable for HTS pancake coils with the following features: 1) nearly self-protecting; 2) significantly smaller charging-delay time constant; and 3) better control of coil parameters. It also permits stable operation at 97% of a quench current. We present 77-K results of NI and MI pancakes: first, comparing the advantages and drawbacks of the two winding techniques and, second, dealing with stability and quench parameters. Finally, using a simple circuit model, we quantitatively show that metallic tape thickness has little detrimental effect on the self-protecting feature of the MI pancakes. © 2002-2011 IEEE. Source

Schussler F.,Institute Of Recherche Sur Les Lois Fondamentales Of Lunivers
Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011

We present the search for the diffuse flux of astrophysical muon neutrinos using data collected by the ANTARES neutrino telescope. We introduce a novel method to estimate the energy of high-energy muons traversing the ANTARES detector and discuss detailed comparisons between data and Monte Carlo simulations. Using data recorded in 2008 and 2009 a search for a high-energy excess over the expected atmospheric neutrino background is presented and stringent limits on the diffuse flux of astrophysical muon neutrinos in the energy range 20 TeV - 2.5 PeV are derived. Source

Schussler F.,Institute Of Recherche Sur Les Lois Fondamentales Of Lunivers
Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011

Clustering of neutrino arrival directions would provide hints for their astrophysical origin. The two-point autocorrelation method is sensitive to a large variety of cluster morphologies and, due to its independence from Monte Carlo simulations, provides complementary information to searches for the astrophysical sources of high energy muon neutrinos. We present the analysis of the autocorrelation function as a function of the angular scale of data collected during 2007-08 with the ANTARES neutrino telescope. Source

Cirelli M.,CERN | Cirelli M.,French National Center for Scientific Research | Moulin E.,Institute Of Recherche Sur Les Lois Fondamentales Of Lunivers | Panci P.,University of Southern Denmark | And 3 more authors.
Physical Review D - Particles, Fields, Gravitation and Cosmology

We derive new bounds on decaying dark matter from the gamma ray measurements of (i)the isotropic residual (extragalactic) background by Fermi and (ii)the Fornax galaxy cluster by H.E.S.S. We find that those from (i)are among the most stringent constraints currently available, for a large range of dark matter masses and a variety of decay modes, excluding half-lives up to ∼1026 to few 1027seconds. In particular, they rule out the interpretation in terms of decaying dark matter of the e ± spectral features in PAMELA, Fermi and H.E.S.S., unless very conservative choices are adopted. We also discuss future prospects for CTA bounds from Fornax which, contrary to the present H.E.S.S. constraints of (ii), may allow for an interesting improvement and may become better than those from the current or future extragalactic Fermi data. © 2012 American Physical Society. Source

Chipaux R.,Institute Of Recherche Sur Les Lois Fondamentales Of Lunivers | Gentit F.-X.,Institute Of Recherche Sur Les Lois Fondamentales Of Lunivers
IEEE Transactions on Nuclear Science

The aging of CMS electronic calorimeter scintillating crystals under radiation leads to a deterioration of their transparency, and thus of their effective light yield and their calibration. The correlation between transparency variation, as measured by the fiber-optic monitoring system, and the calibration variation depends on the optical properties of the scintillating material itself and of its environment. In previous studies, the possibility of light scattering within the bulk of the crystals was not taken into account. We present here the results of the simulation of this correlation for different types of CMS electronic calorimeter crystals using the program Litrani improved to allow light scattering in bulk. They show that scattering could explain the variation of correlation coefficients observed between CMS/ECAL endcap and barrel crystals.. Source

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