Underground Neutrino Detector

Underground Neutrino Detector

. The original solar neutrino detector located 1,500 meters underground in the Homestake Gold Mine, near Lead, South Dakota, to filter out strong signals from energetic cosmic particles. The huge cylindrical tank was filled with 100,000 gallons of cleaning fluid. When a high-energy solar neutrino interacted with the nucleus of a chlorine atom in the fluid, radioactive argon was produced, which was extracted to count the solar neutrinos. This experiment operated for more than 25 years, always finding fewer neutrinos than expected from the Standard Solar Model. (Courtesy of Brookhaven National Laboratory.)

Copyright 2010, Professor Kenneth R. Lang, Tufts University