34 research outputs found
Calibration and Characterization of the IceCube Photomultiplier Tube
Over 5,000 PMTs are being deployed at the South Pole to compose the IceCube
neutrino observatory. Many are placed deep in the ice to detect Cherenkov light
emitted by the products of high-energy neutrino interactions, and others are
frozen into tanks on the surface to detect particles from atmospheric cosmic
ray showers. IceCube is using the 10-inch diameter R7081-02 made by Hamamatsu
Photonics. This paper describes the laboratory characterization and calibration
of these PMTs before deployment. PMTs were illuminated with pulses ranging from
single photons to saturation level. Parameterizations are given for the single
photoelectron charge spectrum and the saturation behavior. Time resolution,
late pulses and afterpulses are characterized. Because the PMTs are relatively
large, the cathode sensitivity uniformity was measured. The absolute photon
detection efficiency was calibrated using Rayleigh-scattered photons from a
nitrogen laser. Measured characteristics are discussed in the context of their
relevance to IceCube event reconstruction and simulation efforts.Comment: 40 pages, 12 figure
Measurement of acoustic attenuation in South Pole ice
Using the South Pole Acoustic Test Setup (SPATS) and a retrievable transmitter deployed in holes drilled for the IceCube experiment, we have measured the attenuation of acoustic signals by South Pole ice at depths between 190 m and 500 m. Three data sets, using different acoustic sources, have been analyzed and give consistent results. The method with the smallest systematic uncertainties yields an amplitude attenuation coefficient α = 3.20 ± 0.57 kmâ1 between 10 and 30 kHz, considerably larger than previous theoretical estimates. Expressed as an attenuation length, the analyses give a consistent result for λ ⥠1/α of âŒ300 m with 20% uncertainty. No significant depth or frequency dependence has been found
Time-integrated Searches for Point-like Sources of Neutrinos with the 40-string IceCube Detector
Search for dark matter from the Galactic halo with the IceCube Neutrino Telescope
Self-annihilating or decaying dark matter in the Galactic halo might produce high energy neutrinos detectable with neutrino telescopes. We have conducted a search for such a signal using 276 days of data from the IceCube 22-string configuration detector acquired during 2007 and 2008. The effect of halo model choice in the extracted limit is reduced by performing a search that considers the outer halo region and not the Galactic Center. We constrain any large-scale neutrino anisotropy and are able to set a limit on the dark matter self-annihilation cross section of âšÏAvâ©â10-22ââcm3âs-1 for weakly interacting massive particle masses above 1 TeV, assuming a monochromatic neutrino line spectrum
Search for a Lorentz-violating sidereal signal with atmospheric neutrinos in IceCube
A search for sidereal modulation in the flux of atmospheric muon neutrinos in IceCube was performed. Such a signal could be an indication of Lorentz-violating physics. Neutrino oscillation models, derivable from extensions to the standard model, allow for neutrino oscillations that depend on the neutrino's direction of propagation. No such direction-dependent variation was found. A discrete Fourier transform method was used to constrain the Lorentz and CPT-violating coefficients in one of these models. Because of the unique high energy reach of IceCube, it was possible to improve constraints on certain Lorentz-violating oscillations by 3orders of magnitude with respect to limits set by other experiments.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Limits on Neutrino Emission from Gamma-Ray Bursts with the 40 String IceCube Detector
IceCube has become the first neutrino telescope with a sensitivity below the TeV neutrino flux predicted from gamma-ray bursts if gamma-ray bursts are responsible for the observed cosmic-ray flux above 10ÂčâžââeV. Two separate analyses using the half-complete IceCube detector, one a dedicated search for neutrinos from pÎł interactions in the prompt phase of the gamma-ray burst fireball and the other a generic search for any neutrino emission from these sources over a wide range of energies and emission times, produced no evidence for neutrino emission, excluding prevailing models at 90% confidence.R. Abbasi ... G. C. Hill ... et al. (IceCube Collaboration
Measurement of the atmospheric neutrino energy spectrum from 100 GeV to 400 TeV with IceCube
A measurement of the atmospheric muon neutrino energy spectrum from 100 GeV
to 400 TeV was performed using a data sample of about 18,000 up-going
atmospheric muon neutrino events in IceCube. Boosted decision trees were used
for event selection to reject mis-reconstructed atmospheric muons and obtain a
sample of up-going muon neutrino events. Background contamination in the final
event sample is less than one percent. This is the first measurement of
atmospheric neutrinos up to 400 TeV, and is fundamental to understanding the
impact of this neutrino background on astrophysical neutrino observations with
IceCube. The measured spectrum is consistent with predictions for the
atmospheric muon neutrino plus muon antineutrino flux.Comment: 19 pages, 24 figures, added background simulation to distribution
plots, clarified a few points in the tex
Search for relativistic magnetic monopoles with the AMANDA-II neutrino telescope: The IceCube Collaboration
IceCube Collaboration Contributions to the 2009 International Cosmic Ray Conference
IceCube Collaboration Contributions to the 2009 International Cosmic Ray
ConferenceComment: Index file for IceCube contributions to the 2009 ICRC; corrected
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