_               _            _
   __ _ _ __ ___   __ _ ___(_)_ __   __ _  | |_ _____  _| |_
  / _` | '_ ` _ \ / _` |_  / | '_ \ / _` | | __/ _ \ \/ / __|
 | (_| | | | | | | (_| |/ /| | | | | (_| | | ||  __/>  <| |_
  \__,_|_| |_| |_|\__,_/___|_|_| |_|\__, |  \__\___/_/\_\\__|
             i have nothing to say  |___/ and i am saying it.
The neutrino, a product of certain nuclear decay reactions, is maddeningly hard to detect, even from the nearby Sun. In the early 1950s, at Brookhaven National Laboratory in Upton, NY, Raymond Davis developed a system for capturing the radioactive argon atoms produced when neutrinos collide with molecules containing chlorine and carbon. He filled a tank in the Homestake Gold Mine in South Dakota with over 600 tons of the dry-cleaning fluid perchloroethylene (C2Cl4), bubbling helium through it to remove the argon produced by neutrinos. The amount of argon then gave a measure of the number of neutrinos that hit the tank.