Measurement of the solar neutrino capture rate with gallium metal

The solar neutrino capture rate measured by the Russian-American Gallium Experiment (SAGE) on metallic gallium during the period January 1990 through December 1997 is ${67.2}_{-7.0-3.0}^{+7.2+3.5\mathrm{}}$ SNU, where the uncertainties are statistical and systematic, respectively. This represents only about half of the predicted standard solar model rate of 129 SNU. All the experimental procedures, including extraction of germanium from gallium, counting of ${}^{71}\mathrm{Ge},$ and data analysis, are discussed in detail.