Sanford Underground Laboratory

The Sanford Underground Research Facility (SURF), formerly Sanford Underground Laboratory at Homestake (or Sanford Lab) is an underground laboratory near Lead, South Dakota, which houses multiple physics experiments in areas such as dark matter and neutrino research. It was initially planned to be part of the United States Department of Energy's Deep Underground Science and Engineering Laboratory (DUSEL) project.

The Homestake mine was a deep underground gold mine founded during the Black Hills Gold Rush in 1876. As the largest and deepest gold mine in North America, Homestake produced more gold than any other mine in the world during its peak years. Over its 125-year lifetime ending in 2001, the mine produced 39.8 million ounces of gold and 9 million ounces of silver.

In the late 1960s, the mine hosted Homestake experiment. The operation, also known as the Davis experiment, allowed Raymond Davis, Jr.'s to measure the flux of solar neutrinos directly. The measurements' discrepancy with the flux predicted from the Sun's luminosity led to Davis's development of the solar neutrino problem. The Homestake experiment publicized the mine as a resource among scientific communities.

The Deep Underground Science and Engineering Laboratory, or DUSEL, was a major project under consideration by the research wings of the United States Department of Energy (DOE). DUSEL was planned to be a series of large laboratories, caverns, and cleanrooms serving the field of underground science. The main impetus for DUSEL was the study of extremely rare nuclear physics processes, like neutrino scattering, dark matter interactions, and neutrinoless double beta decay, which can only be studied in the absence of cosmic rays. (Cosmic ray muons on the Earth's surface cause backgrounds in these types of detectors, but the particles cannot penetrate great depths in rock.) Easy access to these great depths will open new frontiers in geomicrobiology, geosciences, and mining engineering, making DUSEL a multidisciplinary facility.

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