Quantum Diaries

This article appeared in Fermilab Today on Jan. 29, 2014.

The Department of Energy recently gave the Muon g-2 experiment approval to proceed to the next phase of design. Photo: Cindy Arnold

2013 was a big year for the Muon g-2 experiment.

Over the summer, the 52-foot-wide electromagnet that forms the core of the experiment was transported from New York to Illinois in a flurry of publicity. Construction began on the building that will house that device and should be completed in the next couple of months.

And in December, the Department of Energy granted Critical Decision 1 approval to the experiment, marking a major milestone and charting the path forward.

Chris Polly, project manager for Muon g-2, said this approval process was the first time that DOE officials have reviewed the entire scope of the experiment, from the design to the cost to the timeline. In order to get to this stage, the collaboration developed a 500-page report, designing and costing every element of the project and then laying those elements out in a schedule consisting of 1,500 activities spanning four years.

“It was an incredible amount of work that required everyone on the collaboration to really focus, thoroughly think through the whole experiment and document it all for the reviewers,” Polly said.

The reviewers were pleased with the work and only had a few recommendations. Most notably, the committee suggested that the experiment team work with the DOE to develop an accelerated schedule.

The review took place in September, and the intervening months were spent working out the timeline and funding profile. The work that had already been done to transport the electromagnet and begin construction of the MC-1 Building helped convince the reviewers that the team could keep to such a schedule.

“CD-1 approval is a very important milestone for the experiment, and we appreciate all the strong support that we received from DOE and the laboratory management in getting us to this point,” said Lee Roberts, co-spokesperson for the experiment.

The Muon g-2 collaboration received more good news this month as well: The omnibus budget bill signed into law on Jan. 17 includes funding to continue the design and begin construction of the experiment. (That funding is not explicitly spelled out in the bill but is covered.)

2014 will be another big year with the reassembly of the storage ring in its new home, the development of detectors for the experiment and the start of construction for the muon source. And this summer the Muon g-2 team will undergo the next step in the approval process, an extensive CD-2 review.

—Andre Salles

This article originally appeared in symmetry on July 26, 2013.

The 50-foot-wide electromagnet for the Muon g-2 experiment has completed its five-week journey from New York to Illinois.

For the last three nights, a big rig has traveled slowly down the roads of suburban Illinois bearing an American flag and the warning sign “Oversize Load.” The warning may have been an understatement.

Its “load” was a 50-foot, 17-ton electromagnet that, for the last month, has voyaged by land and by sea from Brookhaven National Laboratory on Long Island. Early this morning, it reached its final destination: Fermi National Accelerator Laboratory outside of Chicago.

The electromagnet arrived accompanied by an impressive entourage: a dozen state trooper cars and more than a handful of county sheriffs and local police, plus crews from a company called Roadsafe, which was tasked with removing roadside signs ahead of the convoy and righting them after it passed. It will make its final move across the laboratory site this afternoon.

The logistics of the move have captured imaginations all along the way. But underneath the spectacle is important, potentially groundbreaking science.

The electromagnet is part of what is known as the Muon g-2 experiment. Scientists on the Muon g-2 experiment study short-lived particles called muons, which wobble when placed in a magnetic field due to an internal conflict between some of their characteristics.

In 2001, Brookhaven scientists used the ring to measure that wobble. Taking into consideration their current understanding of physics, scientists can predict what it should be like. If it turns out to be different than expected, it could indicate the presence of new physics.

In the first iteration of this experiment, Brookhaven physicists found hints that the wobble was off. Relocating the experiment to Fermilab will allow it to run in a more intense particle beam (for less money than it would cost to build the experiment anew), giving a more precise answer.

“We’ve been trying for years to really determine whether we’ve discovered something new and exciting,” says Muon g-2 Spokesperson Lee Roberts, who began working on the experiment in 1984. “We’re all excited to see the answer. It’s exciting for me personally, and it’s exciting for science.”

To relocate the magnet, the Muon g-2 team worked for over a year with Emmert International, a company that subsists on moving big, unwieldy objects, to plan the journey, which involved constructing a bright red fixture to hold the ring in place (prompting many observers along the way to compare it to a UFO).

The ring is an exquisitely sensitive device; it cannot be bent or twisted by more than a few millimeters.

“This is one of the widest, most fragile, dimensionally unusual, temperamental projects we’ve done,” says Terry Emmert, owner of Emmert International. “It’s amazing to see it all come together.”

The ring first saw daylight in mid-June, when a team from Emmert slid it out of the building that had housed it since the 1990s. After a week’s rain delay, it traveled six miles along Long Island’s William Floyd Parkway—in about half the expected time of six hours—to the Smith Point Marina, where it was loaded by crane onto a 50-by-150-foot barge and pulled by a pair of tugboats out to sea.

“The crane is just enormous,” says Chris Polly, the Muon g-2 project manager at Fermilab. “It’s a 500-ton capacity crane that’s four or five stories high, so you can pick up this device that weighs 60 tons [with the support structure] and get it on the barge. The whole procedure went pretty smoothly.”

From there, the barge—essentially a giant floating plank—faced 3200 miles of ocean and river waters and a month’s worth of unpredictable summer weather. First it floated from Long Island down the East Coast and around Florida. The barge was forced to camp out for five nights in Norfolk, Virginia, to wait out a passing tempest. After that, the barge narrowly escaped brewing tropical storm Chantal.

After rounding the tip of Florida, the barge was scheduled to move directly up the Mississippi. Due to heavy currents, which would have caused barges to back up at the locks, the team decided to take a back-roads alternative, maneuvering up the Tombigbee Waterway and the Tennessee River. On July 12, the ring made a stop in Mobile, Alabama, where Trident, the ocean-going tugboat, handed the barge off to Miss Katie, a white tugboat with red trim that coordinated nicely with the red support structure for the electromagnet wrapped in white plastic.

Miss Katie pushed the barge into the Mississippi and ultimately to Lemont, Illinois, where—after a brief pit stop in the wrong port—it greeted a cast of more than 100 scientists, family members and curious onlookers on July 20.

The ring will complete its cross-country trip later today, but its second chance at searching for new physics has just begun.

—Laura Dattaro

This Fermilab press release came out on May 8. Read the original press release.

A model of the truck that will be used to transport the Muon g-2 ring, placed on a streetscape for scale. The truck will be escorted by police and other vehicles when it moves from Brookhaven National Laboratory in New York to a barge, and then from the barge to Fermi National Accelerator Laboratory in Illinois. Credit: Fermilab

Scientists from 26 institutions around the world are planning a new experiment that could open the doors to new realms of particle physics. But first, they have to bring the core of this experiment, a complex electromagnet that spans 50 feet in diameter, from the U.S. Department of Energy’s Brookhaven National Laboratory in New York to the DOE’s Fermi National Accelerator Laboratory in Illinois.

The experiment is called Muon g-2 (pronounced gee-minus-two), and will study the properties of muons, tiny subatomic particles that exist for only 2.2 millionths of a second. The core of the experiment is a machine built at Brookhaven in the 1990s, and the centerpiece of that machine is a circular electromagnet made of steel and aluminum, 50 feet wide, with superconducting cable inside.

“It costs about 10 times less to move the magnet from Brookhaven to Illinois than it would to build a new one,” said Lee Roberts of Boston University, spokesperson for the Muon g-2 experiment. “So that’s what we’re going to do. It’s an enormous effort from all sides, but it will be worth it.”

While most of the machine can be disassembled and brought to Fermilab in trucks, the massive electromagnet must be transported in one piece. It also cannot tilt or twist more than a few degrees, or the complex wiring inside will be irreparably damaged. The Muon g-2 team has devised a plan to make the 3,200-mile journey that involves loading the ring onto a specially prepared barge and bringing it down the East Coast, around the tip of Florida and up the Mississippi River to Illinois.

The ring is expected to leave New York in early June, and land in Illinois in late July. Once it arrives, the ring will be placed onto a truck built just for this purpose, and driven to Fermilab in Batavia, a suburb of Chicago. The land transport portions on both the New York and Illinois ends of the trip will occur at night—to minimize traffic delays—and the truck will only travel, at most, 10 miles per hour. On the New York end, the trip from Brookhaven Lab’s gate to the departure port should take one night. The complete trip from the Illinois port to Fermilab should take two consecutive nights.

“The transport of the ring from Brookhaven to Fermilab is a great example of the cooperation that exists between national laboratories,” said James Siegrist, associate director of science for high-energy physics with the U.S. Department of Energy. “The Muon g-2 experiment is an important component of the future of particle physics in the United States.”

Once at Fermilab, the storage ring will be used to hold muons created in the laboratory’s accelerators. Muons “wobble” when placed in a magnetic field, and based on what we know about the universe, scientists have predicted the exact value of that wobble. An experiment using the same machine at Brookhaven in the 1990s saw evidence for – though not definitive proof of – a departure from that expected value.

“Fermilab can generate a much more intense and pure beam of muons, so the Muon g-2 experiment should be able to close that margin of error,” said Chris Polly, project manager for Fermilab. “If we can do that, this experiment could indicate that there is exciting science awaiting beyond what we have observed.”

The experiment is scheduled to begin taking data in 2016.

“The ring is a wonder of scientific engineering,” said William Morse of Brookhaven. “We’re extremely proud of it, and excited to see it used in this next-generation experiment.”