A world-class lab, 8,000 feet underground

An old gold mine in South Dakota could become a site for unlocking secrets about the sun and the nature of matter.

For 126 years, generations of miners working South Dakota's Homestake Mine have brought a king's ransom in gold to the surface.

Now, US researchers want to turn the facility into a scientific gold mine.

Five scientists, backed by a broad array of researchers from around the world, have sent the federal government a formal plan to turn the mine into a $281-million national lab.

Scheduled to close in December, the mine represents a rare opportunity to explore fundamental mysteries of science at depths - up to 8,000 feet - that proponents say will shut out the "noise" triggered by cosmic rays in the atmosphere.

They say the world-class facility could help unlock the secrets of the sun's furnace, test theories about the nature of matter, provide fresh insights into the origins of life on earth and the prospects for life elsewhere in the solar system, and be a testbed for a new generation of computer chips.

Scientists at the US Naval Research Laboratory in Gaithersburg, Md., add that the facility would be valuable in examining air or dust samples for evidence of nuclear weapons tests.

"There is no doubt that this would be a great institution, if it's created," says John Bahcall, an astrophysicist at the Institute for Advanced Studies at Princeton University in New Jersey.

He led a panel that explored the scientific rationale for a National Underground Science Laboratory.

Homestake is no stranger to science. For the past 30 years, it has hosted a pioneering underground experiment designed to detect small, virtually massless subatomic particles streaming from the sun. The experiment uses a steel tank filled with 600 tons of cleaning fluid to detect the passage of these particles, called neutrinos, that flow from thermonuclear reactions at the sun's core.

Led by Ray Davis from the University of Pennsylvania, the team that installed the detector found that the sun appeared to generate only about one-third the number of neutrinos predicted by theories describing the sun's reactions.

Latest underground find

This week, another underground lab appeared to put the wraps on the mystery of the sun's missing neutrinos.

The facility, in Sudbury, Ontario, used a new detector bearing 1,000 tons of heavy water. The results, combined with those reported in 1998 by a group using the Super Kamiokande detector beneath Japan's Mt. Ikenoyama, indicate that solar neutrinos switch back and forth among three types as they travel. The "missing" neutrinos merely had morphed themselves into types that early detectors couldn't pick up when the neutrinos passed through them.

The results also gave clues about the neutrinos' masses, which the Sudbury team reckons could represent collectively up to 18 percent of the matter and energy that comprise the density of the universe.

Despite Sudbury's proximity to the US, the US research community needs such a facility for several reasons, say scientists involved with the new proposal.

Research that bears on fundamental questions about the nature of matter and the history of the universe involve detecting signals that can be swamped by incoming cosmic rays. The problem is compounded as detectors grow more sensitive. Doing experiments deep underground shields them from such effects. Homestake would be the deepest underground lab in the world.

Moreover, the mine's nearly 500 miles of tunnels would provide plenty of experimental space, with much of the needed ventilation, electrical supply, and other pieces of infrastructure already in place.

Finally, many of the researchers who need to work deep underground must travel to countries such as Russia, Italy, Japan, or South Africa to find suitable spots for their experiments. A US lab would allow them to spend more money on getting results and less on travel.

Noting that the US has research facilities on land, on orbit, and under the sea, Joe Dehmer of the National Science Foundation (NSF) adds, "Where you have a totally exotic environment, you have advances in science."

Centerpiece: a neutrino telescope

The plan's architects, led by University of Washington physicist Wick Haxton, want to anchor the lab with neutrino "telescope" 10 times Super Kamiokande's 50,000-ton mass. The detector could cost some $500 million.

Although the notion of an multidisciplinary underground lab has been floated for years, the Homestake proposal surfaced only last September, after the mine's parent company said it was closing the facility, says Sherry Farrwell, of the South Dakota School of Mines and Technology in Rapid City. She was one of five researchers who submitted the plan to the NSF on June 6.

In addition to science, the facility also would produce jobs for the community of Lead, whose 3,500 residents currently rely on the mine for their livelihood. The lab's potential for luring scientists and even tourists to the area has drawn strong support from state and local officials, as well as the state's congressional delegation - which includes the new Senate majority leader, Tom Daschle (D).

The proposal is now being reviewed by an independent panel of scientists.

Yet even if it passes scientific muster, fiscal hurdles remain. NSF's budget has remained virtually flat for several years, even as US scientists have placed increasing demands on the research-funding agency for big-ticket facilities. Even if the NSF includes Homestake in its fiscal 2003 budget request, it still must pass muster with the White House.

"Whether the lab is approved or not, it has heightened the attention of very important people in the Senate to the value of science," Dr. Bahcall says.

(c) Copyright 2001. The Christian Science Monitor

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