Physicists in South Dakota have started assembling "detector units" in the search for a rare form of radioactive decay that could help explain how the universe evolved.
The Majorana Demonstrator Experiment is under construction in the Davis Campus of a shuttered gold mine in Lead in the Black Hills. It's next door to another experiment meant to detect dark matter.
Both experiments are housed nearly a mile beneath the earth in the former Homestake Gold Mine. Officials with the Sanford Underground Research Facility say that the first detector units were built through Monday when physicist Ryan Martin "attached a polished germanium-crystal detector the size of a hockey puck to a wafer-thin glass electronics board."
The experiment will need about 70 such units to search for neutrinoless double-beta decay.