109 research outputs found
A geoneutrino experiment at Homestake
A significant fraction of the 44TW of heat dissipation from the Earth's
interior is believed to originate from the decays of terrestrial uranium and
thorium. The only estimates of this radiogenic heat, which is the driving force
for mantle convection, come from Earth models based on meteorites, and have
large systematic errors. The detection of electron antineutrinos produced by
these uranium and thorium decays would allow a more direct measure of the total
uranium and thorium content, and hence radiogenic heat production in the Earth.
We discuss the prospect of building an electron antineutrino detector
approximately 700m^3 in size in the Homestake mine at the 4850' level. This
would allow us to make a measurement of the total uranium and thorium content
with a statistical error less than the systematic error from our current
knowledge of neutrino oscillation parameters. It would also allow us to test
the hypothesis of a naturally occurring nuclear reactor at the center of the
Earth.Comment: proceedings for Neutrino Sciences 2005, submitted to Earth, Moon, and
Planet
A Monte Carlo simulation of the Sudbury Neutrino Observatory proportional counters
The third phase of the Sudbury Neutrino Observatory (SNO) experiment added an
array of 3He proportional counters to the detector. The purpose of this Neutral
Current Detection (NCD) array was to observe neutrons resulting from
neutral-current solar neutrino-deuteron interactions. We have developed a
detailed simulation of the current pulses from the NCD array proportional
counters, from the primary neutron capture on 3He through the NCD array
signal-processing electronics. This NCD array Monte Carlo simulation was used
to model the alpha-decay background in SNO's third-phase 8B solar-neutrino
measurement.Comment: 38 pages; submitted to the New Journal of Physic
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Low-Multiplicity Burst Search At The Sudbury Neutrino Observatory
Results are reported from a search for low-multiplicity neutrino bursts in the Sudbury Neutrino Observatory. Such bursts could indicate the detection of a nearby core-collapse supernova explosion. The data were taken from Phase I (1999 November-2001 May), when the detector was filled with heavy water, and Phase II (2001 July-2003 August), when NaCl was added to the target. The search was a blind analysis in which the potential backgrounds were estimated and analysis cuts were developed to eliminate such backgrounds with 90% confidence before the data were examined. The search maintained a greater than 50% detection probability for standard supernovae occurring at a distance of up to 60 kpc for Phase I and up to 70 kpc for Phase II. No low-multiplicity bursts were observed during the data-taking period.Natural Sciences and Engineering Research Council, CanadaIndustry Canada, CanadaNational Research Council, CanadaNorthern Ontario Heritage Fund, CanadaAtomic Energy of Canada, Ltd., CanadaOntario Power Generation, CanadaHigh Performance Computing Virtual Laboratory, CanadaCanada Foundation for Innovation, CanadaCanada Research Chairs, CanadaDepartment of Energy, USNational Energy Research Scientific Computing Center, USAlfred P. Sloan Foundation, USScience and Technology Facilities Council, UKFundacao para a Ciencia e a Technologia, PortugalAstronom
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Searches For High-Frequency Variations In The B-8 Solar Neutrino Flux At The Sudbury Neutrino Observatory
We have performed three searches for high-frequency signals in the solar neutrino flux measured by the Sudbury Neutrino Observatory, motivated by the possibility that solar g-mode oscillations could affect the production or propagation of solar B-8 neutrinos. The first search looked for any significant peak in the frequency range 1-144 day(-1), with a sensitivity to sinusoidal signals with amplitudes of 12% or greater. The second search focused on regions in which g-mode signals have been claimed by experiments aboard the Solar and Heliospheric Observatory satellite, and was sensitive to signals with amplitudes of 10% or greater. The third search looked for extra power across the entire frequency band. No statistically significant signal was detected in any of the three searches.Natural Sciences and Engineering Research Council, CanadaIndustry Canada, CanadaNational Research Council, CanadaNorthern Ontario Heritage Fund, CanadaAtomic Energy of Canada, Ltd., CanadaOntario Power Generation, CanadaHigh Performance Computing Virtual Laboratory, CanadaCanada Foundation for InnovationDept. of Energy, USNational Energy Research Scientific Computing Center, USScience and Technologies Facilities Council, UKAstronom
Low Multiplicity Burst Search at the Sudbury Neutrino Observatory
Results are reported from a search for low-multiplicity neutrino bursts in
the Sudbury Neutrino Observatory (SNO). Such bursts could indicate detection of
a nearby core-collapse supernova explosion. The data were taken from Phase I
(November 1999 - May 2001), when the detector was filled with heavy water, and
Phase II (July 2001 - August 2003), when NaCl was added to the target. The
search was a blind analysis in which the potential backgrounds were estimated
and analysis cuts were developed to eliminate such backgrounds with 90%
confidence before the data were examined. The search maintained a greater than
50% detection probability for standard supernovae occurring at a distance of up
to 60 kpc for Phase I and up to 70 kpc for Phase II. No low-multiplicity bursts
were observed during the data-taking period.Comment: 11 pages, 4 figures, submitted to Ap
Combined Analysis of all Three Phases of Solar Neutrino Data from the Sudbury Neutrino Observatory
We report results from a combined analysis of solar neutrino data from all
phases of the Sudbury Neutrino Observatory. By exploiting particle
identification information obtained from the proportional counters installed
during the third phase, this analysis improved background rejection in that
phase of the experiment. The combined analysis resulted in a total flux of
active neutrino flavors from 8B decays in the Sun of (5.25 \pm
0.16(stat.)+0.11-0.13(syst.))\times10^6 cm^{-2}s^{-1}. A two-flavor neutrino
oscillation analysis yielded \Deltam^2_{21} = (5.6^{+1.9}_{-1.4})\times10^{-5}
eV^2 and tan^2{\theta}_{12}= 0.427^{+0.033}_{-0.029}. A three-flavor neutrino
oscillation analysis combining this result with results of all other solar
neutrino experiments and the KamLAND experiment yielded \Deltam^2_{21} =
(7.41^{+0.21}_{-0.19})\times10^{-5} eV^2, tan^2{\theta}_{12} =
0.446^{+0.030}_{-0.029}, and sin^2{\theta}_{13} =
(2.5^{+1.8}_{-1.5})\times10^{-2}. This implied an upper bound of
sin^2{\theta}_{13} < 0.053 at the 95% confidence level (C.L.)
Independent measurement of the total active B8 solar neutrino flux using an array of He3 proportional counters at the Sudbury Neutrino Observatory
The Sudbury Neutrino Observatory (SNO) used an array of 3He proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active (νx) 8B solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5.54-0.31+0.33(stat)-0.34+0.36(syst)×106  cm-2 s-1, in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields Δm2=7.59-0.21+0.19×10-5  eV2 and θ=34.4-1.2+1.3 degrees. The uncertainty on the mixing angle has been reduced from SNO’s previous results
A Search for Neutrinos from the Solar hep Reaction and the Diffuse Supernova Neutrino Background with the Sudbury Neutrino Observatory
A search has been made for neutrinos from the hep reaction in the Sun and from the diffus
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