The Talk of the Lab

Fermilab is a haven for nuts. Not only do we have large numbers of ordinary nuts, but rare nuts, nuts scarcely present anywhere else, thrive at the laboratory. Nuts love it here.

Take, for example, the kingnut, a variety of hickory, Carya laciniosa, of which the Fermilab site has the only native trees in northeastern Illinois. The definitive "Plants of the Chicago Region," by Swink and Wilhelm, which lists "all the plants that have been reliably recorded as growing wild here at any time since scientific collection began," assigns every Chicagoland plant a "coefficient of conservatism," from zero to 10. The higher the coefficient, the more likely it is that the plant comes from a remnant natural plant community--in other words, that it was part of the original landscape of the area, before the arrival of settlers, sodbusting and strip malls. A dandelion, for instance, gets a zero coefficient: it's definitely not rare, and it's a European immigrant. In contrast, a certain rare species of native prairie aster might get a 6 or a 7.

If, like Fermilab, you are trying to restore an area to something approximating its natural pre-McDonald's state, the appearance of species with high coefficients of conservatism is good. It means you're working your way back to the way things were. Thus, a couple of weeks ago, prairie experts were elated to discover blooming in the Fermilab prairie a downy gentian, Gentiana puberulenta, a beautiful little flower of a brilliant blue, with a coefficient of conservatism equal to 9. Its appearance means the Fermilab prairie restoration is doing fine. The downy gentian likes it here.

Coefficient-wise, the kingnut is a 10.

Here's what Swink and Wilhelm have to say about the kingnut: "A tree of floodplain and bottomland woods...still present in remnant woods in the Kankakee River Valley in Indiana....Mike Becker and Bob Lootens discovered a large population of this handsome tree at Fermilab in Kane County, where old, open-grown trees grow in a drained woodland..." Our kingnuts are famous.

As the name implies, the nuts of the kingnut are big, a good three inches in diameter, including the husk. A recent foray to the kingnut stand at the height of nut season, however, turned up very few nuts. Prairie guru Mike Becker, one of the kingnut trees' discoverers, explained that squirrels had gotten there first.

"Squirrels love them," Becker said. "They are the t-bone steak of nuts, If you want to find a kingnut, you practically have to catch it on the way down."

Just then, a nut fell off the tree. We caught it. The squirrels are onto something. It was delicious.

The Metaphors of Physics

High-energy physicists are heavy users of the metaphor and its (metaphorical) cousin, the simile. How else to explain to the world's non-physicists how a top quark looks (like a bowling ball) or how a particle detector is put together (like a Russian matryoshka doll)? Naturally, some figures of speech work better than others. A recent comparison of the number of particle collisions required to find a top quark with the size of the national debt led at least some readers to conclude that the former might have a causal relationship to the latter. An explanation of the action of the hypothetical Higgs boson in terms of the progress of former British Prime Minister Margaret Thatcher through a roomful of diplomats left many (metaphorically) scratching their heads.

But there is one expression that physicists universally embrace. They invariably use this phrase to convey the challenge of managing each other, a notoriously difficult task that becomes more difficult--some would say impossible--as the number of the managed increases. Ask the project manager for any particle detector construction or upgrade project in the world this question: How do you get hundreds of independent-minded, independently funded physicists to agree on, design, engineer and build a multimillion-dollar state-of-the-art instrument for doing frontier physics? One and all will say the same thing: "It's like herding cats."

"It's like herding cats," physicists say, with a mixture of exasperation, ruefulness and pride. It's more than a metaphor--it's a management principle. And it has far-reaching applications.

For example, on October 4, the New York Times reported that "It took a physicist to galvanize many of New York City's most important cultural institutions to take a stand in the battle over the `Sensation' show at the Brooklyn Museum of Art." The "Sensation" show, you may recall, is the one with the elephant dung and the pornographic cut-outs, the show of which New York Mayor Giuliani took such a dim view that he threatened to cut the museum's funding.

Physicist Alan J. Friedman, director of the New York Hall of Science, is chairman of New York's Cultural Institutions Group, made up of directors of such institutions as the Metropolitan Museum of Art and the American Museum of Natural History. Last week, Friedman rallied his colleagues in the Group to stick up for the Brooklyn Museum's right to exhibit what it chose, and to ask the mayor to change his mind.

Apparently it wasn't easy to persuade the Cultural Institutions Group to sign a letter protesting the "chilling effect" of the mayor's threat, but in the end even non-member museums like the Museum of Modern Art, the Whitney and the Guggenheim signed on. How did Friedman, the physicist, whose thesis topic was "Specific Heat of MnBr₂ Near the Critical Point," get so many of the directors of New York's most distinguished cultural institutions to act as one? No problem.

"It was like herding cats," Friedman said.

There's Thumping about Fermi

Fermilab's farflung facilities, all the accelerators, detectors, beamlines, workshops, labs, offices and so on that make up a physics lab, are knit together by hundreds of miles of underground electrical cable, carrying the power that operates everything on the site from superconducting magnets to light bulbs. As the cables age, they wear, and from time to time they break. The power stops, the lights go off, and the time has come to thump.

When you need to pinpoint the location of a fault in an electrical cable several feet underground, so that you can fix it, you do something called thumping. At Fermilab, we call 1-888-THUMPER, and the thumping experts from High Voltage Electric are on their way.

The first step in faultfinding is to identify the faulty cable and turn off the power source so that no electricity is flowing into it. Next, the thumping crew sends a small voltage, say 100 volts from a battery, into the cable. An instrument attached to the cable gives a general idea, within a couple of hundred feet, of the location of the fault.

Now, the thumping crew is ready for the main event. With a sudden discharge from a capacitor, they send a large jolt of power-- 7,000 volts or so-- into the cable. When it reaches the fault--THUMP!

"You can hear it and you can feel it," says Joe Pathiyil, Fermilab supervisor of high-voltage engineering. Using probes inserted in the ground, and with a few more thumps, sometimes at higher voltage, the thumpers can tell exactly where the fault lies.

Then what?

"Then," says David Nevin, head of the Facilities Engineering Section, "we dig."

by Judy Jackson