Limits on diffuse fluxes of high energy extraterrestrial neutrinos with the AMANDA-B10 detector

Data from the AMANDA-B10 detector taken during the austral winter of 1997 have been searched for a diffuse flux of high energy extraterrestrial muon-neutrinos, as predicted from, e.g., the sum of all active galaxies in the universe. This search yielded no excess events above those expected from the background atmospheric neutrinos, leading to upper limits on the extraterrestrial neutrino flux. For an assumed E^-2 spectrum, a 90% classical confidence level upper limit has been placed at a level E^2 Phi(E) = 8.4 x 10^-7 GeV cm^-2 s^-1 sr^-1 (for a predominant neutrino energy range 6-1000 TeV) which is the most restrictive bound placed by any neutrino detector. When specific predicted spectral forms are considered, it is found that some are excluded.Comment: Submitted to Physical Review Letter

Muon Track Reconstruction and Data Selection Techniques in AMANDA

The Antarctic Muon And Neutrino Detector Array (AMANDA) is a high-energy neutrino telescope operating at the geographic South Pole. It is a lattice of photo-multiplier tubes buried deep in the polar ice between 1500m and 2000m. The primary goal of this detector is to discover astrophysical sources of high energy neutrinos. A high-energy muon neutrino coming through the earth from the Northern Hemisphere can be identified by the secondary muon moving upward through the detector. The muon tracks are reconstructed with a maximum likelihood method. It models the arrival times and amplitudes of Cherenkov photons registered by the photo-multipliers. This paper describes the different methods of reconstruction, which have been successfully implemented within AMANDA. Strategies for optimizing the reconstruction performance and rejecting background are presented. For a typical analysis procedure the direction of tracks are reconstructed with about 2 degree accuracy.Comment: 40 pages, 16 Postscript figures, uses elsart.st

Sensitivity of the IceCube Detector to Astrophysical Sources of High Energy Muon Neutrinos

We present the results of a Monte-Carlo study of the sensitivity of the planned IceCube detector to predicted fluxes of muon neutrinos at TeV to PeV energies. A complete simulation of the detector and data analysis is used to study the detector's capability to search for muon neutrinos from sources such as active galaxies and gamma-ray bursts. We study the effective area and the angular resolution of the detector as a function of muon energy and angle of incidence. We present detailed calculations of the sensitivity of the detector to both diffuse and pointlike neutrino emissions, including an assessment of the sensitivity to neutrinos detected in coincidence with gamma-ray burst observations. After three years of datataking, IceCube will have been able to detect a point source flux of E^2*dN/dE = 7*10^-9 cm^-2s^-1GeV at a 5-sigma significance, or, in the absence of a signal, place a 90% c.l. limit at a level E^2*dN/dE = 2*10^-9 cm^-2s^-1GeV. A diffuse E-2 flux would be detectable at a minimum strength of E^2*dN/dE = 1*10^-8 cm^-2s^-1sr^-1GeV. A gamma-ray burst model following the formulation of Waxman and Bahcall would result in a 5-sigma effect after the observation of 200 bursts in coincidence with satellite observations of the gamma-rays.Comment: 33 pages, 13 figures, 6 table

New results from the Antarctic Muon And Neutrino Detector Array

We present recent results from the Antarctic Muon And Neutrino Detector Array (AMANDA) on searches for high-energy neutrinos of extraterrestrial origin. We have searched for a diffuse flux of neutrinos, neutrino point sources and neutrinos from GRBs and from WIMP annihilations in the Sun or the center of the Earth. We also present a preliminary result on the first energy spectrum above a few TeV for atmospheric neutrinos.Comment: 8 pages, 8 figures, to be published in Nuclear Physics B (Proceedings Supplement): Proceedings of the XXIst International Conference on Neutrino Physics and Astrophysics, Paris, June 14-19, 200

Search for Neutrino-Induced Cascades with AMANDA

We report on a search for electro-magnetic and/or hadronic showers (cascades) induced by high energy neutrinos in the data collected with the AMANDA II detector during the year 2000. The observed event rates are consistent with the expectations for atmospheric neutrinos and muons. We place upper limits on a diffuse flux of extraterrestrial electron, tau and muon neutrinos. A flux of neutrinos with a spectrum $\Phi \propto E^{-2}$ which consists of an equal mix of all flavors, is limited to $E^2 \Phi(E)=8.6 x 10^{-7} GeV/(cm^{2} s sr)$ at a 90% confidence level for a neutrino energy range 50 TeV to 5 PeV. We present bounds for specific extraterrestrial neutrino flux predictions. Several of these models are ruled out.Comment: 18 pages, 12 figure

Предварительное исследование применения системы спектрального регулирования для ТВС реактора ВВЭР-1000

Повышение топливных характеристик ядерных реакторов за счет применения концепции управления спектральным сдвигом (SSC) вместо традиционных методов, основанных на поглощении, является многообещающим подходом к снижению стоимости топливного цикла и увеличению использования топливных ресурсов (U, Pu). В данной работе было проведено исследование применения химического метода SSC для модели топливной сборки ВВЭР-1000 с низкообогащенным ураном, в которой контроль реактивности осуществляется путем изменения доли D2O относительно легководного замедлителя (D2O/H2O), и сравнение с поглощающими материалами, в которых содержится 600 ppm H3BO3 и 4,0 мас.% Gd2O3

Flux limits on ultra high energy neutrinos with AMANDA-B10

Abstract Data taken during 1997 with the AMANDA-B10 detector are searched for a diffuse flux of neutrinos of all flavors with energies above 10 16 eV. At these energies the Earth is opaque to neutrinos, and thus neutrino induced events are concentrated at the horizon. The background are large muon bundles from down-going atmospheric air shower events. No excess events above the background expectation are observed and a neutrino flux following E À2 , with an equal mix of all flavors, is limited to E 2 U(10 15 eV < E < 3 · 10 18 eV) 6 0.99 · 10 À6 GeV cm À2 s À1 sr À1 at 90% confidence level. This is the most restrictive experimental bound placed by any neutrino detector at these energies. Bounds to specific extraterrestrial neutrino flux predictions are also presented. Ó 2004 Elsevier B.V. All rights reserved. PACS: 95.55.Vj; 95.85.Ry; 96.40.T

Results from the AMANDA detector

The Antarctic Muon And Neutrino Detector Array (AMANDA) is a high-energy neutrino telescope based at the geographic South Pole. It is a lattice of photo-multiplier tubes buried deep in the polar ice, which is used as interaction and detection medium. The primary goal of this detector is the observation of astronomical sources of high-energy neutrinos. This paper shows the latest results of the search for a diffuse flux of extraterrestrial \u3bd\u3bcs with energies between 1011 eV and 10 18 eV, \u3bd\u3bcs emitted from point sources and \u3bd\u3bcs from dark matter annihilation in the Earth and the Sun