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Impact and History

Our History

In 2006, the Homestake Gold Mine transitioned into a dedicated underground research facility where scientists probe the depths of space to learn more about our place in the universe.
Ray Davis look in a tank being built for a solar neutrino experiment.

The Sanford Underground Research Facility (SURF) houses world-leading physics experiments that could give us a better understanding of the universe. Located at the former Homestake Gold Mine in Lead, S.D., SURF provides significant depth and rock stability—a near-perfect environment for experiments that need to escape cosmic radiation that can interfere with the detection of rare physics events. Until its closure in 2002, Homestake was the largest and deepest gold mine in North America, producing approximately 41 million ounces of gold in its 126-year lifetime.

Davis looks at hit neutrino tank during construction.

Early Physics Research

The idea of housing physics research at Sanford Lab came long before its official conversion to a research facility. The first physics experiment came to Homestake Mine in the mid-1960s when Dr. Ray Davis, a chemist from Brookhaven National Lab, began building his solar neutrino experiment on the 4850 Level. Despite nearly three decades of counting neutrinos, Davis consistently found only one-third of the number predicted. This became known as the solar neutrino problem. Eventually the problem was solved through new understandings in neutrino physics. By the time Ray Davis received the Nobel Prize in Physics in 2002, the deep caverns of the mine were coveted for continued particle physics research. 

When the Homestake Mine closed in 2002, the National Science Foundation (NSF) had already considered the facility as a possible future sight for the United States’ Deep Underground Science and Engineering Laboratory (DUSEL). Barrick Gold Corporation agreed to keep the pumps running while discussions about the facility's future as a research facility were underway. However, soaring costs caused the company to turn off the pumps just one year later.

Denny Sanford and infrastructure technicians

Built on partnerships

In 2006, a donation of $70 million from T. Denny Sanford, for whom the facility is named, breathed new life into the creation of a deep underground research facility in the United States. Barrick Gold Corporation made a land donation and the State of South Dakota formed the South Dakota Science and Technology Authority (SDSTA), a quasi-government entity and committed more than $40 million. These developments culminated with the creation of the Sanford Underground Research Facility in 2007. 

After an extensive dewatering process, the 4850 Level of Sanford Lab was dedicated in 2009. Dignitaries from around the country, including then-South Dakota Governor Mike Rounds and T. Denny Sanford attended the event. The underground dedication took place in a space now designated as Governor’s Corner.

The Davis Campus is open for science

Change in direction

In December 2010, the National Science Board decided not to fund further design of DUSEL. However, in 2011 the Department of Energy (DOE), through the Lawrence Berkeley National Laboratory, agreed to support science operations. Today, the DOE funding is managed through Fermi National Accelerator Laboratory (Fermilab), with additional funding through the SDSTA. 

The first two major physics experiments located on the 4850 Level were the Large Underground Xenon (LUX) experiment and the Majorana Demonstrator Project. Majorana was housed in a new transition cavern. LUX was housed in the renovated Davis Cavern, where Ray Davis ran his Nobel Prize-winning solar neutrino experiment for nearly three decades. 

The first two major physics experiments located on the 4850 Level were the Large Underground Xenon (LUX) experiment and the Majorana Demonstrator Project. Majorana was housed in a new transition cavern. LUX was housed in the renovated Davis Cavern, where Ray Davis ran his Nobel Prize-winning solar neutrino experiment for nearly three decades. 

In October 2013, after an initial run of 80 days, LUX was determined to be the most sensitive dark matter detector in the world. Further analysis confirmed that result in 2016, the same year the experiment was decommissioned.

The Majorana Demonstrator is searching for a rare type of radioactive decay called neutrinoless double-beta decay, which requires extreme quiet. If this phenomenon were detected, it could confirm that neutrinos are their own antiparticles and provide clues as to why matter prevailed over antimatter. In a study published in 2018, Physical Review Letters, the Majorana collaboration showed they can shield a sensitive, scalable, 44-kilogram germanium detector array from background radioactivity. 

LUX PMTs

The LUX experiment

When LUX completed its 300-live-day run in May of 2016, the world learned LUX was even more sensitive than previously determined.
A researcher works on a cryostat inside a glovebox.

MAJORANA Demonstrator

The Majorana Demonstrator experiment could help us understand the imbalance of matter and antimatter in the universe—and tell us why we exist at all.

Beginning in 2015, other projects and experiments began moving to the 4850 Level, including CASPAR, a low-compact accelerator that seeks to learn how elements heavier than iron were formed in collapsing stars. 

Future experiments include the second generation dark matter experiment, LUX-ZEPLIN (LZ), and the Long-Baseline Neutrino Facility and associated Deep Underground Neutrino Experiment (LBNF/DUNE). LZ is currently being installed in the Davis Cavern and is expected to be operational by 2020. In 2017, the LBNF/DUNE collaboration held a groundbreaking on the 4850 Level of Sanford Lab to mark the start of pre-excavation.