Physicists to break ground underground

Dawn Throener

Scientists and government officials will go a half mile below the earth’s surface today to break ground on a lab that could solve the mysteries surrounding subatomic particles called neutrinos.
The under-ground breaking will take place at 2:30 p.m. in the Soudan Underground Mine State Park in northern Minnesota.
Housed in a former mining cave, the lab will hoist a 10,000 ton steel neutrino detector that will help determine whether neutrinos have mass. The lab is a joint effort sponsored by the U.S. Department of Energy, the United Kingdom, the state of Minnesota, the University and other institutions. The University is funding $3 million of the project’s total cost of $130 million.
“It’s a big feather in the cap, and it makes the University look good in the physics lab,” said Louis Barrett, professor of physics at Western Washington University.
Fermi National Accelerator Laboratory, a research facility 40 miles west of Chicago run by the Department of Energy, will shoot neutrinos underground to the detector in Soudan. The neutrinos will travel 450 miles and are estimated to arrive a fraction of a second later.
Physicists will try to determine whether neutrinos change their characteristics between their collection in Chicago and their final destination in Soudan. A difference in their characteristics could reveal whether they have mass.
Led by Stanford University investigator Stanley Wojcicki, the Main Injector Neutrino Oscillation Search would also involve about 200 scientists from five countries.
If experiments prove that neutrinos don’t have mass, current physics theories will be on solid ground.
“(That) is the boring answer,” Barrett said.
Although for a long time neutrinos were thought to be without mass, recent experiments suggest otherwise. There is an estimated 300 million neutrinos per square meter in the universe.
“Neutrinos shoot through the earth and don’t hit a lot of things,” said Barrett. “That’s why we don’t know much about them.”
If a neutrino collides with the nucleus of an atom in the detector, a shower of subatomic particles would be produced in the steel. Ten billion neutrinos have to go through the detector before one collides; about 12,000 neutrino interactions are expected.
The discovery that neutrinos have mass could explain “dark matter” in the universe. Some scientists think 90 percent of the universe is composed of dark matter, or matter that doesn’t emit light or any detectable radiation. Neutrinos might compose 10 percent of dark matter, scientists suspect.
Neutrinos are present on almost every atom, but they are difficult to study because their behavior is unpredictable. The Soudan experiment differs from others in the past in the level of control involved in the research.
“We’re in control this time, that’s why we’re going to learn more,” Barrett said.
Although the lab construction begins today, the neutrino detector will not be finished until 2001, and will not start detecting subatomic particles until 2003, said Earl Peterson, a University professor in physics involved with the project.
Some of the people attending the under-ground breaking include Professor Wojcicki, Dr. John O’Fallon from the Department of Energy, Michael Witherell, director of Fermilab, Peterson and other Minnesota state and University officials.