SAGE (Soviet–American Gallium Experiment, or sometimes Russian-American Gallium Experiment) is a collaborative experiment devised by several prominent physicists to measure the solar neutrino flux.
Contents
The Experiment
SAGE was devised to measure the radio-chemical solar neutrino flux based on the inverse beta decay reaction, 71Ga
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 January 2010) 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 7001654000000000000♠65.4+3.1
−3.0 (stat.) +2.6
−2.8 (syst.) SNU. This represents only 56%-60% of the capture rate predicted by different Standard Solar Models, which predict 138 SNU. The difference is in agreement with neutrino oscillations.
The collaboration has used a 518 kCi 51Cr neutrino source to test the experimental operation. The energy of these neutrinos is similar to the solar 7Be neutrinos and thus makes an ideal check on the experimental procedure. The extractions for the 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 7000100000000000000♠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 37Ar neutrino source had been performed.
Members of SAGE
SAGE is led by the following physicists: