A review of the homestake solar neutrino experiment

Abstract

The observations from the Homestake radiochemical solar neutrino experiment over the period 1970 to 1992 are given. The observations will be compared to those from the Kamiokande II experiment, the gallium experiments and solar model calculations. A discussion is given of the question of a possible variation of the solar neutrino flux in anticorrelation with the solar activity cycle. The operation of the Homestake experiment, the sensitivity to the solar neutrino spectrum, the background processes and the various tests that have been performed are given in some detail. The Homestake and Kamiokande II experiments are compared on the basis of the standard model and the flux of 8B neutrinos. There is agreement between these two experiments during the period June 1987 to April 1990 when both experiments were observing. The average 8B neutrino flux during this period was (2.2 ± 0.2) × 10 6 cm −2sec −1. A non-standard solar model of Sienkiewicz, Bahcall, and Paczynski (1990) which presumes that 50% of the core of the Sun is continually mixed on a slow time scale accounts for this reduced 8B flux and the total neutrino capture rate of the chlorine and gallium experiments.