The need for deep science

February 6, 2012

Technicians constructing the large chlorine tank for the Davis neutrino experiment in 1965

Deep underground laboratories shield sensitive physics experiments from the interference of cosmic radiation. The key word is depth, for which there is no substitute. Nuclear chemist Ray Davis first recognized the Homestake gold mine's potential for deep science in the mid-1960s. Davis installed a neutrino detector 4,850 feet underground at Homestake in the mid-1960s. In 2002 he was awarded a Nobel Prize for Physics for that work. The mine closed in 2003, but the state of South Dakota and a team of scientists kept the dream of underground research alive. In 2012, the Sanford Underground Research Facility opened the Davis Campus, named for the Nobel laureate, at the 4850 Level. Protected by nearly a mile of rock, the Davis Campus is more than a million times quieter than laboratories on the surface.

The water tank for the Large Underground Xenon (LUX) dark matter experiment, seen here in May 2012, in the same cavern excavated for the Davis neutrino experiment on the 4850 Level.

The need for a facility like the Sanford Lab in the United States has been documented in more than a dozen scientific reports, from the Bahcall Committee Report in 2001 to the National Research Council’s “Assessment of the Deep Underground Science and Engineering Laboratory” in 2011. The NRC report noted, “Researchers from the United States who are interested in pursuing experiments that require these ultra-quiet spaces have typically worked in collaboration with others in large underground facilities built in Europe, Japan, and Canada.” (See Reports and Assessments.)

The NRC report identified three underground physics experiments “of paramount importance.” They are:

  • A direct-detection dark-matter experiment on a scale of one to tens of tons
  • A long-baseline neutrino oscillation experiment
  • A ton-scale, neutrinoless double-beta decay experiment

The Sanford Lab offers the quiet environments required by all three of those experiments. Two such experiments are being installed in the Davis Campus in 2012. The Large Underground Xenon (LUX) experiment will search for dark matter. The Majorana Demonstrator project will search for neutrinoless double-beta decay. The Department of Energy in 2012 is reviewing proposals for the Long Baseline Neutrino Experiment (LBNE), which would fire a beam of neutrinos from an accelerator at Fermilab near Chicago to a detector at the Sanford Lab, 800 miles away.

In addition, biologists and geologists already are conducting research at the Sanford Lab.

The menu on the left links to some of the experiments either under way or being planned for the Sanford Lab.