According to the Soudan Mine interpretive program, the region around northern Minnesota’s Lake Vermilion was settled by gold prospectors in 1865. Though gold was never found, the aspiring miners soon located some of the purest and most plentiful iron ore deposits on the planet. By 1954, the Soudan Mine had been sunk almost a half-mile below the Earth’s surface.
After ceasing operations in 1962, the US Steel Corporation donated the Soudan Mine to the state of Minnesota, which today operates it as the Soudan Underground Mine State Park. The elevator to the twenty-seventh and deepest level, down Shaft No. 8, now transports tourists instead of miners. And, at 7:30 a.m. and 4:30 p.m., it transports the people who have reclaimed and expanded the mine as a physics lab.
It is late midmorning in the long office pod that hovers beside the MINOS detector. David Lee Roth’s “Yankee Rose” blasts from the office manager’s PC, while an assortment of physicists drink their morning coffee and discuss the day’s work plan with the lab crew. It’s a collegial environment where associations often date back to grad school (in the case of the physicists) or high school (in the case of the locally hired lab crew). Hierarchies are mostly non existent, with all parties focused on the daunting task of making the detector and its software run correctly. Professor Louis Barrett of Western Washington University, the MINOS far detector’s grandfatherly data acquisition coordinator, offers that “Maury’s the guy who thought of shooting a neutrino beam at the mine.” He gestures toward Dr. Maury Goodman, a gentle-mannered physicist from the Argonne National Laboratory outside Chicago, who is quietly reading his email. Goodman shyly mumbles something about “other people,” but his wife (who describes herself as “just a wife”), busy at the computer behind him, proudly bursts in, “I called my brother and said, ‘You won’t believe what he’s thought of now.’”
Goodman smiles uncomfortably and steps outside the pod to an exhibit that explains MINOS to the small number of Soudan Underground Laboratory visitors who don’t understand particle physics. He likens the experiment to “trying to hit the moon with a flashlight—the trick is being able to see the flashlight from the moon. That’s why we have to build something big.” He gestures with his laser pointer at the enormous detector. “I mean, it takes that to stop a few thousand neutrinos per year.” It is estimated that only nine thousand neutrinos will be stopped out of the five trillion that make the .0025-second trip from Fermilab in Illinois to (and through) the far detector in a year’s worth of runs. “And the reason to come up here, five hundred miles away from Chicago, is that we thought that there might be something going on with oscillation at that scale,” Goodman says, spreading his hands. “You couldn’t do this experiment using only ten or twenty meters.”
Back in the fluorescent-lit office pod, Bill Miller settles into his squeaky chair, in a cubicle squeezed to prison-cell proportions by computers, collapsing bookshelves, boxes of MINOS T-shirts, and stacks of binders. As lab manager, the forty-eight-year-old Miller is responsible for lab logistics, and over the last decade, he has been largely responsible for the design and installation of the far detector. But construction management skills alone are not enough to get a multi-million-dollar experimental apparatus built. It’s also necessary to have a fundamental understanding of the science involved in using that apparatus, and so Miller holds the additional title of assistant scientist. “Usually you’d have a Ph.D. in my job,” he admits, acknowledging that “I took an unusual path.” That’s an understatement, perhaps, considering Miller doesn’t even have a B.A.
Born in Florida to a minister in charge of the Presbyterian Church’s missionary program, Miller spent his childhood summers traveling among missionary camps in a VW van. In 1959, the family visited the Iron Range, and soon after bought a cabin on Snowbank Lake. “Essentially, I’ve been coming to the Ely area my entire life,” he explains. Now he and his wife (he has two grown children from a prior marriage) live outside Ely, in a house Miller constructed himself in the mid-1970s. It’s a modest-looking place from the outside, but the interior walls are lined in fine woods and wainscoted with the swirling copper patterns of cathode boards salvaged from a proton decay experiment.
Though Miller obtained a perfect GPA in his first year as a math major at the University of Southern Connecticut, he found greater satisfaction working as a guide in the Boundary Waters during the summer of 1974. He stayed in northern Minnesota, and “my parents were incredibly bummed,” he recalls with a laugh. (Though it was little solace to his parents, Miller was a phenomenal guide: A 1974 article from All Outdoors magazine extols his skills and concludes by comparing him to French-Canadian voyageurs who “wore earrings and let their hair fall to their waists.”)
To makes ends meet, Miller worked construction in the off-season. But construction, too, could be erratic, and in the winter of 1985 Miller was unemployed. Fortunately, the new lab manager for the Soudan Underground Laboratory, a neighbor of Miller’s, offered him a temporary job in civil construction. At the time, the lab was expanding from its modest roots as “found space” for the proton decay experiments developed by Earl Peterson and his colleagues into a facility capable of hosting multi-million-dollar experimental apparatuses. Miller remembers it as “a really cool job” where he spent his first two months “hauling muck in pails,” and “spending a month on the twenty-fifth level alone with a headlamp.” “He was just really smart, and could do whatever needed to be done,” Peterson recalls. Eventually, Miller’s employment was extended to the construction of the much larger and more complicated Soudan Two proton decay detector in a newly excavated space on the twenty-seventh level. “By the third or fourth month I started working with physicists,” Miller recounts.
The first formal proposals for the MINOS experiment were drawn up in 1990, but it was another four years before formal research and development began. When it did, Miller (who had become lab manager in 1991) played a leading role, developing most of the procedures and protocols necessary to construct the far detector at the Soudan Underground Lab. In total, eight years of planning took place before the detector’s first plate was assembled in the freshly excavated cavern.
“When you’re half a mile underground, it really is like trying to shove the ship back into the bottle,” Miller explains. “Everything had to come down in that four-by-six-foot elevator car. Every last piece of equipment, all six thousand kilotons of detector.” For example, a front-end loader was totally disassembled on the surface, lowered to the twenty-seventh level in pieces (each tire required one elevator trip), and reassembled underground. Each of the detector’s 486 plates was assembled from eight pieces of half-inch thick steel measuring six by twenty-seven feet, which were cut precisely to fit inside the elevator in six-ton bundles. On the other end, approximately 657,000 cubic feet of excavated material from the new cavern was brought to the surface. In all, the cavern excavation and detector construction required 29,613 one-way elevator trips (at a cost of $30 per trip), over twenty-three months. These were not trivial operations. In fact, Miller tested them in an exact mockup of the elevator car and head-frame that was built, along with a detector prototype, at Fermilab in Illinois.