The timeline of solar neutrinos and their discovery dates back to the 1960s, beginning with the two astrophysicists John N. Bahcall and Raymond Davis Jr. The experiment, known as the Homestake experiment, named after the town in which it was conducted (Homestake, South Dakota), aimed to count the solar neutrinos arriving at Earth. Bahcall, using a solar model he developed, came to the conclusion that the most effective way to study solar neutrinos would be via the chlorine-argon reaction. Using his model, Bahcall was able to calculate the number of neutrinos expected to arrive at Earth from the Sun. Once the theoretical value was determined, the astrophysicists began pursuing experimental confirmation. Davis developed the idea of taking hundreds of thousands of liters of perchloroethylene, a chemical compound made up of carbon and chlorine, and searching for neutrinos using a chlorine-argon detector. The process was conducted very far underground, hence the decision to conduct the experiment in Homestake as the town was home to the Homestake Gold Mine. By conducting the experiment deep underground, Bahcall and Davis were able to avoid cosmic ray interactions which could affect the process and results. The entire experiment lasted several years as it was able to detect only a few chlorine to argon conversions each day, and the first results were not yielded by the team until 1968. To their surprise, the experimental value of the solar neutrinos present was less than 20% of the theoretical value Bahcall calculated. At the time, it was unknown if there was an error with the experiment or with the calculations, or if Bahcall and Davis did not account for all variables, but this discrepancy gave birth to what became known as the solar neutrino problem.