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| '''SAGE''' ('''''S'''oviet–'''A'''merican '''G'''allium '''E'''xperiment'', or sometimes ''Russian-American Gallium Experiment'') is a collaborative experiment devised by several prominent [[physicists]] to measure the [[solar neutrino]] [[flux]].
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| ==The Experiment==
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| '''SAGE''' was devised to measure the [[Radiochemistry|radio-chemical]] solar neutrino flux based on the [[inverse beta decay]] [[Chemical reaction|reaction]], <sup>71</sup>Ga<math>\left(\nu_e,e^{-}\right)</math><sup>71</sup>Ge. The target for the reaction was 50-57 tonnes of liquid [[gallium]] metal stored deep underground at the [[Baksan Neutrino Observatory]] in the [[Caucasus mountains]] in [[Russia]]. About once a month, the neutrino induced [[Germanium|Ge]] is extracted from the [[Gallium|Ga]]. <sup>71</sup>Ge is unstable with respect to [[electron capture]] (<math>t_{1/2}=11.43</math> days) and, therefore, the amount of extracted [[germanium]] can be determined from its activity as measured in small [[proportional counter]]s. | |
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| The experiment had begun to measure the solar neutrino capture rate with a target of gallium metal in December 1989 and is running up to now ({{as of|2010|January|lc=y}}) with only a few brief interruptions. The experiment has measured the solar neutrino flux in 168 extractions between January 1990 and December 2007. The current result of the experiment based on the whole 1990-2007 set of data is 65.4 +3.1/-3.0 ([[statistical]]) +2.6/-2.8 ([[systematic]]) [[Solar neutrino unit|SNU]]. This represents only 56%-60% of the capture rate predicted by different [[Standard Solar Model]]s, which predict 138 SNU.
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| The collaboration has used a 518 k[[Curie|Ci]] <sup>51</sup>Cr neutrino source to test the experimental operation. The energy of these neutrinos is similar to the solar <sup>7</sup>Be neutrinos and thus makes an ideal check on the experimental procedure. The extractions for the [[Chromium|Cr]] experiment took place between January and May 1995 and the counting of the samples lasted until fall. The result, expressed in terms of a ratio of the measured production rate to the expected production rate, is 1.0±0.15. This indicates that the discrepancy between the solar model predictions and the SAGE flux measurement cannot be an experimental artifact. Also calibrations with a <sup>37</sup>Ar neutrino source had been performed.
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| ==Members of SAGE==
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| SAGE is led by the following [[physicists]]:
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| *[[Vladimir Gavrin]]
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| *[[Georgiy Zatsepin]] ([[Joint Institute for Nuclear Research]], Russia)
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| *[[Tom Bowles]] ([[Los Alamos National Laboratory|Los Alamos]])
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| ==See also==
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| * [[GALLEX]]/GNO was the second (of two) large gallium-germanium radiochemical experiment. It was running in 1991-2003.
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| *[[Hans Bethe]] was the architect of the [[theory]] of [[nuclear fusion]] reactions in [[star]]s.
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| *The [[University of Washington]] is playing a major role in the [[statistical analysis]] of the SAGE data and in the determination of systematic uncertainties. They are very active in the remaining analysis of the Cr experiment data as well as the solar neutrino data.
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| ==Literature==
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| * SAGE Collaboration. [http://dx.doi.org/10.1103/PhysRevC%2E80%2E015807 Measurement of the solar neutrino capture rate with gallium metal. III: Results for the 2002--2007 data-taking period]. Phys.Rev. C80:015807, 2009. See also [http://arxiv.org/abs/0901.2200 arXiv:0901.2200]
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| ==External links==
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| * [http://ewi.npl.washington.edu/sage The web page of the experiment] in the [[University of Washington]]
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| *[http://cat.inist.fr/?aModele=afficheN&cpsidt=4077673 Old page (1994) with results of the experiments]
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| * [http://www.inr.ru/rus/ins_sotr/sl78r.html Some results (2001)] {{ref-ru}}
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| *[http://www.webofstories.com/people/hans.bethe/151 Hans Bethe talking about SAGE] (video)
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| {{Neutrino detectors}}
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| {{DEFAULTSORT:Sage (Soviet-American Gallium Experiment)}}
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| [[Category:Particle experiments]]
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| [[Category:Soviet Union–United States relations]]
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| [[Category:Science and technology in the Soviet Union]]
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| [[Category:Science and technology in the United States]]
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| [[Category:Science and technology in Russia]]
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The author's name is Christy. Credit authorising is exactly where my main earnings comes from. Playing badminton is a factor that he is completely addicted to. My wife and I live in Mississippi and I love each day living right here.
Also visit my blog; good psychic