Deep science at the frontier of physics

The Yates Shaft headframe, left, behind the Yates Administration Building.

The Sanford Underground Research Facility in Lead, South Dakota, will advance our understanding of the universe by providing laboratory space deep underground, where sensitive physics experiments can be shielded from cosmic radiation. Researchers at the Sanford Lab will explore some of the most challenging questions facing 21st century physics, such as the origin of matter, the nature of dark matter and the properties of neutrinos. The facility also hosts experiments in other disciplines—including geology, biology and engineering.

The Majorana Demonstrator assembly room

The LUX dark matter detector, inside its water tank

The Sanford Lab is located at the former Homestake gold mine, which was a physics landmark long before it was converted into a dedicated science facility. Nuclear chemist Ray Davis earned a share of the Nobel Prize for Physics in 2002 for a solar neutrino experiment he installed 4,850 feet underground in the mine.

Homestake closed in 2003, but the company donated the property to South Dakota in 2006 for use as an underground laboratory. That same year, philanthropist T. Denny Sanford donated $70 million to the project. The South Dakota Legislature also created the South Dakota Science and Technology Authority to operate the lab. The state Legislature has committed more than $40 million in state funds to the project, and South Dakota also obtained a $10 million Community Development Block Grant to help rehabilitate Homestake.

In 2007, after the National Science Foundation named Homestake as the preferred site for a proposed national Deep Underground Science and Engineering Laboratory (DUSEL), the South Dakota Science and Technology Authority (SDSTA) began reopening the former gold mine.

In December 2010, the National Science Board decided not to fund further design of DUSEL. However, in 2011 the Department of Energy, through the Lawrence Berkeley National Laboratory, agreed to support ongoing science operations at the the Sanford Lab, while investigating how to use Homestake for other longer-term experiments. The SDSTA, which owns the Sanford Lab, continues to operate the facility under that agreement with Berkeley Lab.

The first two major physics experiments at the Sanford Lab are being installed 4,850 feet underground in an area called the Davis Campus, named for the late Ray Davis. The Large Underground Xenon (LUX) experiment been installed in the same cavern excavated for Ray Davis in the 1960s. LUX will be the most sensitive detector yet to search for dark matter—a mysterious, yet-to-be-detected substance thought to be the most prevalent matter in the universe. The Majorana Demonstrator experiment, also being installed in 2012, will search for a rare phenomenon called “neutrinoless double-beta decay” that could reveal whether subatomic particles called neutrinos can be their own antiparticle. Detection of neutrinoless double-beta decay could help determine why matter prevailed over antimatter. The Majorana Demonstrator experiment is in a newly excavated space in the Davis Campus, adjacent to the original Davis cavern.

The Department of Energy also is considering the Sanford Underground Research Facility as the site for proposed longer term experiments, such as the Long-Baseline Neutrino Experiment (LBNE) and a project called Dual Ion Accelerators for Nuclear Astrophysics (DIANA).