Measurement of the Solar Electron Neutrino Flux with the Homestake Chlorine Detector

The Homestake Solar Neutrino Detector, based on the inverse beta-decay reaction ν e + 37 Cl → 37 Ar + e - , has been measuring the flux of solar neutrinos since 1970. The experiment has operated in a stable manner throughout this time period. All aspects of this detector are reviewed, with particular emphasis on the determination of the extraction and counting efficiencies, the key experimental parameters that are necessary to convert the measured 37 Ar count rate to the solar neutrino production rate. A thorough consideration is also given to the systematics of the detector, including the measurement of the extraction and counting efficiencies and the nonsolar production of 37 Ar. The combined result of 108 extractions is a solar neutrino-induced 37 Ar production rate of 2.56 ± 0.l6 (statistical) ± 0.16 (systematic) SNU.