Status of solar neutrino measurements

A radiochemical neutrino detector was built by Brookhaven National Laboratory in 1965-1967 to observe the neutrino flux from the Sun and thereby test the thermal fusion theory of the solar energy. The experiment depends upon the neutrino capture reaction nu/sub e/ + 37Cl → 37Ar + e- that produces the 35 day radio-isotope 37Ar. The experiment uses 615 metric tons of C2Cl4 as a neutrino capturing medium. The detector is located 1480 meters below the surface to reduce background effects from cosmic radiation. The 37Ar is removed from the liquid by a helium purge, purified and the 37Ar activity is measured in a miniature proportional counter. Results will be reported on 68 individual measurements performed during the period 1970-1985. The results will be discussed in relation to theoretical models of the sun, current ideas in neutrino physics, and solar activity