Looking Back: Remembering Petaluma’s ‘giant sphere’
“Sphere Holds Key to Future: Structure designed to trap and examine subatomic particles.”
That was the headline of a story run a quarter-century ago in the Argus-Courier, describing the conspicuous presence of a 40,000-pound metallic geosphere, created by a team of machinists and metal workers at Petaluma’s Donal Machine, Inc. As explained in that article (See excerpt in sidebar), the massive ball of shiny metal was commissioned as part of a major scientific experiment to examine the nature of subatomic dun particles. The sphere was eventually transported to an underground cavern in Canada, where the 10-year-long experiment took place.
“This is one of the photo-cell devices that would detect the neutrinos,” says Bob Bergstedt, Vice President of Donal Machin, holding up an object that somewhat resembles a small spotlight. Bergstedt was there when the company his father founded, in 1969, undertook the project of creating the enormous sphere to which hundreds of those sensors were eventually attached. “We built the sphere out of stainless steel tubing, four-inches in diameter,” he says. “It was made like an erector set, and it had to all disassemble because it was going down into that mine. We assembled it in our parking lot, to prove out that it was really going to go together.”
Donal Machine has since moved a bit south of the spot where the company, and its parking lot, was located in 1993, part of the property now used by Lagunitas Brewing Company.
“The parking lot was big,” he recalls. “It would be problematic to hang that same thing from a crane in the parking lot we have here. When we made the parts, they had to get washed and rinsed in deionized water, then dried, then immediately be fit into a plastic sleeve, because that was a basically a giant ‘clean room’ down there in the mine. Everything has to be spotless. There was a company in Southern Petaluma called Stero Dishwashing, and they helped with the washing before the think was packed on pallets and hauled up to Sudbury.”
There is a wall in the front office at Donal Machine, on which a number of framed commendations and certificates of recognition are hanging, each presented by various politicians or organizations in honor of Donal Machine’s contributions to the important scientific project.
“It was interesting because after we made it, with all of these people saying, ‘Hurry up, get it done, the deadline’s looming,’” Bergstedt recalls, “but the wheels of science move slowly, so once we finished it and sent it up to Canada, it evidently sat for eight months before they finally got around to reassembling it underground. I think the cavern wasn’t quite down being built yet.”
Asked if he ever had a chance to visit the Sudbury Neutrino Observatory, Bergstedt – whose sister Donna is CEO of Donal, and whose brother Chris is President – allows that only his father, Don Bergstedt, made the trek up to Canada.
“This whole thing was Dad’s baby,” he says. “This was the biggest thing we’ve ever done, easily, and probably the biggest thing we’ll ever do, and Dad was pretty proud of it. It was a long process, but it was really exciting to be a part of something like that, and something so important.”
As for the results of the neutrino experiment, Bergstedt says he kept tabs of progress of the project, and admits they all felt a twinge of pride when the 2015 Nobel Prize in Physics was awarded to Art McDonald, the director of the experiment.
“It did prove the theory that neutrinos have mass, by the way,” Bergstedt says. “I’m no expert on the scientific part of it, but I know that proving neutrinos have mass solves some major scientific quandary. To know what that quandary was, I guess you’d have to ask some genius, I guess.”
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