36 research outputs found
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
Search for Point Sources of High Energy Neutrinos with AMANDA
This paper describes the search for astronomical sources of high-energy
neutrinos using the AMANDA-B10 detector, an array of 302 photomultiplier tubes,
used for the detection of Cherenkov light from upward traveling
neutrino-induced muons, buried deep in ice at the South Pole. The absolute
pointing accuracy and angular resolution were studied by using coincident
events between the AMANDA detector and two independent telescopes on the
surface, the GASP air Cherenkov telescope and the SPASE extensive air shower
array. Using data collected from April to October of 1997 (130.1 days of
livetime), a general survey of the northern hemisphere revealed no
statistically significant excess of events from any direction. The sensitivity
for a flux of muon neutrinos is based on the effective detection area for
through-going muons. Averaged over the Northern sky, the effective detection
area exceeds 10,000 m^2 for E_{mu} ~ 10 TeV. Neutrinos generated in the
atmosphere by cosmic ray interactions were used to verify the predicted
performance of the detector. For a source with a differential energy spectrum
proportional to E_{nu}^{-2} and declination larger than +40 degrees, we obtain
E^2(dN_{nu}/dE) <= 10^{-6}GeVcm^{-2}s^{-1} for an energy threshold of 10 GeV.Comment: 46 pages, 22 figures, 4 tables, submitted to Ap.
Physics Results from the AMANDA Neutrino Detector
In the winter season of 2000, the AMANDA (Antarctic Muon And Neutrino Detector Array) detector was completed to its final state. We report on major physics results obtained from the AMANDA-B10 detector, as well as initial results of the full AMANDA-II detector
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
Long-term survival of breast cancer patients with brain metastases: Subanalysis of the BMBC registry
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
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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 E2*dN/dE = 7*10^-9 cm^-2s^-1GeV at a 5-sigma significance, or, in the absence of a signal, place a 90 percent c.l. limit at a level E2*dN/dE = 2*10^-9 cm^-2s^-1GeV. A diffuse E-2 flux would be detectable at a minimum strength of E2*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