Why Physicists Tried to Put a Ferret in a Particle Accelerator

In February 1971, physicists at the Nationwide Accelerator Laboratory in Batavia, Illinois, started testing the largest machine on the earth: a ring-shaped, 200-billion-electron-volt (BeV*) proton synchrotron particle accelerator. The stakes have been excessive. NAL director Bob Wilson had instructed the U.S. Division of Vitality that he may get it working inside 5 years for $250 million, they usually have been 4 years in. They quickly ran right into a perplexing drawback: Magnets that have been important to its operation stored failing.

The low-tech answer proposed for this high-tech hassle? A ferret named Felicia.

However first, a little bit of background. The NAL—at present often called Fermilab, after the physicist Enrico Fermi—has a series of accelerators: a linear accelerator (linac), a booster, a recycler ring, and a primary injector ring. The linac supplies the proton beam and the preliminary jolt of vitality; the booster accelerates it; the recycler “batches it” into teams of protons for a extra intense beam; and the primary injector ring zips the beam round tens of 1000’s of occasions to almost the velocity of sunshine. The particles are then despatched to numerous testing amenities, the place they’re smashed collectively or towards a set goal. The ensuing collision, noticed by a particle detector, reveals their interiors and typically creates unique particles. These are probably the most basic components of the universe.

Again in 1971, the design was a little bit completely different; for one factor, the injector and recycler rings didn’t exist. What did was an accelerator 4 miles round known as the primary ring. It was outfitted with magnets, which information the beam by means of the accelerators: “774 dipole magnets—which steer the particle beam—and 240 quadrupole magnets—which focus the beam,” because the physicist Ryuji Yamada, who designed the dipole magnet, recalled.

These aren’t fridge magnets: Every is 20 ft lengthy and weighs practically 13 tons. At first, simply two magnets failed when the glass fiber insulation round their coils broke. That quickly turned two a day. Over the subsequent a number of months, the crew changed 350 magnets.

But on June 30, 1971, they managed to ship a beam of particles all the way in which across the ring for the primary time. By August, they despatched one round 10,000 occasions. However after they tried to speed up the particles above seven BeV, the magnets shorted out.

Yamada lastly realized the trigger: metallic slivers left behind after they lower into the vacuum tubes. “So when the magnets have been excited to the next subject,” he wrote, “they have been pulled contained in the magnet hole, stood up and stopped the beam, as a result of they have been barely magnetic materials.”

They needed to get the slivers out. However how?

Robert Sheldon, a British engineer who’d been introduced on to NAL to search out “shortcuts and money-saving concepts,” instructed a ferret, outfitted with a cleansing instrument, may do the job, scampering by means of the vacuum tubes as if flushing rabbits out of a warren. “In his a part of Yorkshire, hunters used ferrets,” Frank Beck, a former head of analysis providers at Fermilab, wrote. “A ferret wouldn’t hesitate to run down the within of the chrome steel tube, even when that concerned an extended journey into the unknown.”

The ferret arrived by particular supply from the Wild Recreation and Fur Farm in Gaylord, Minnesota. At 15 inches lengthy, she was the smallest ferret they’d had. Her fur was brown and black apart from white patches on her face. They known as her Felicia. She price $35.

They positioned a customized collar round Felicia’s neck and a diaper round her rear; ferret poop in a tube would cease a proton, too. They connected a string to the collar. Felicia was to deliver the string from one finish of a tube to the opposite. Then they’d connect a cleanser-dipped swab to the string and pull it by means of.

However Felicia refused to enter the primary ring vacuum tube. Maybe she was daunted by the slim, lightless black loop—it was 4 miles round.

Confronted with a recalcitrant ferret, the scientists reassigned her to a bit of 12-inch-wide tubes within the Meson Lab, a testing facility that was nonetheless beneath building. “She was taught to scamper by means of progressively longer tunnels till she was able to attempt one of many 300-foot sections that might be joined collectively to make the Meson Lab’s tubes,” Time famous.

After her first run, she emerged “trying a little bit drained and bemused however in any other case fairly wholesome,” based on Beck. She’d pulled the string throughout. As deliberate, workmen pulled the swab by means of the tubes. It got here out lined with specks of mud and metal.

The media quickly caught wind of her escapades. After she made seven profitable runs, Time questioned whether or not she needs to be rewarded with mate. An unnamed official responded, “If Felicia turned pregnant, she won’t match by means of the tubes.”

Felicia probably wasn’t in any hazard throughout her runs, says Valerie Higgins, Fermilab’s archivist and historian. “The sections she ran by means of have been nonetheless beneath building, so I might assume they wouldn’t have any energy working to them at that stage,” she says. “So far as getting caught or suffocated goes: I believe they have been simply counting on a ferret’s intuition to discover tunnels, so I don’t assume she would have gone down a tunnel too small for her.”

The NAL workers doted on Felicia, feeding her rooster, liver, fish heads, and uncooked hamburger—her favourite. Some staff even took Felicia to their dwelling for the night time when the mink farm she typically bunked at had no room for her.

In the meantime, the engineer Hans Kautzky created a “magnetic ferret” to cope with the particles in the primary ring. He connected a dozen Mylar disks to a stainless-steel rod, together with a versatile, 700-meter chrome steel cable—the equal of Felicia’s string—and a metal-attracting everlasting magnet—the counterpart to the cleansing swab. He shot the system by means of a bit of the primary ring with compressed air. “With 12 operations, we may make it across the complete ring,” Yamada wrote. “This fashion we may clear the entire vacuum pipe, although not completely.”

But it surely labored effectively sufficient, as a result of over the subsequent a number of months, the crew steadily turned up the vitality ranges with out shorting out the system, and on March 1, 1972, they bought the accelerator to succeed in the goal vitality of 200 BeV.

After a dozen runs by means of the Meson Lab tubes—which, when joined, grew too lengthy for her consolation—Felicia went into semi-retirement, and spent most of her time as a pet on the mink farm. One night time the next spring, she was on the dwelling of Charles Crose, a NAL worker, when she fell ailing. Crose took her to a vet the subsequent day. Below medical care, she briefly rallied, however inside a few days she died, on Could 9, 1972. A necropsy revealed a ruptured abscess in her intestinal tract. The Village Crier noted, “It’s deliberate that Felicia’s physique might be stuffed and mounted to be displayed completely as a logo of early NAL growth.”

But when Felicia was taxidermied, there’s no document of it. “I’ve by no means discovered any proof that that occurred, and no person remembers that ever taking place,” says Higgins, who tried to trace down individuals who labored with Felicia or might need extra details about her destiny after dying. She had no luck. Many have since died.

Most historic artifacts related to Fermilab are in a space for storing Higgins manages. Is there any probability she’s hiding within the again someplace, deep on a shelf?

“It appears most unlikely,” Higgins says. “I might love if I discovered that, however there’s not too many corners at this level that any individual hasn’t been into.”

In the present day Fermilab is considered one of 17 nationwide labs and has a number of particle accelerators. Of the 13 recognized subatomic particles within the Normal Mannequin of the universe—six quarks, six leptons, and the Higgs-Boson—three have been discovered there: the underside quark in 1977, the highest quark in 1995, and the tau neutrino in 2000.

The accelerator advanced operates 24 hours a day, year-round, apart from a few deliberate durations when it’s shut down for any upkeep, based on Andre Salles, a Fermilab spokesperson. It’s then that the tubes could also be cleaned. For shorter sections, the accelerator operators connect a rag to an extended stick and run it by means of. If it’s an extended tunnel, they use the tactic Felicia made well-known: “They normally use some form of string,” Salles says, “and simply pull the swab by means of.”

* Replace: In the present day GeV, for gigaelectron volts, is extra generally used for this unit.