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Peel and stick "Considering the number of Russians in the Tevatron department at the time, it seemed like a fun idea," says Edstrom, who studied some Russian in college. "I should also mention that it was the midnight shift, which made the fun seem even better." The labels, which mark two crucial monitors displaying the bend of the Tevatron’s beamline as it moves through the tunnel, proved amusing—especially to the Russians. Vsevolod "Seva" Kamerdzhiev is one of the many who have enjoyed Edstrom’s creative grammar. On the labels Edstrom had written "this is horizontal" and "this is vertical," instead of simply "horizontal" and "vertical." "The words do exist—they just wouldn’t be used in a case like this," Kamerdzhiev says. The grammatical errors were easy ones to make as only the endings of the words were incorrect, thus changing their meanings. Still, Kamerdzhiev appreciates the gesture. "The Russian labels give a nice feeling
of being welcome," he says.
Tesla in paradise Maybe it’s the loud buzz and crackle of artificial lightning bolts, writhing like fiery serpents from the top of the thing.
Maybe it’s the hint of danger: More than one million volts! Stay back behind the ropes, and turn off your cell phone! Paulina Shearer and her brother, Andrew, watched wide-eyed, hands over their ears, as a volunteer, safely enclosed in a clunky metal suit, came forward to do battle with the flashing electrical arcs (Look folks, he’s safe! Give him a hand!). "It was cool," six-year-old Paulina said, "but kind of freaky." The scene was the second annual Maker Faire in San Mateo, California, put on in late May by the publishers of Make, a magazine devoted to do-it-yourself technology projects. Terry Schalk and Hartmut Sadrozinski, adjunct professors of physics at the Santa Cruz Institute of Particle Physics, haul the Tesla coil to schools about 10 times a year, using it to lure kids into the world of science. Their demonstrations span everything from atoms and galaxies to how particle accelerators work.
"This is just enough entertainment to catch the attention of students. It’s enough real physics to actually present some meat," says Schalk, who works on experiments at the Stanford Linear Accelerator Center (SLAC). "We use it to tell them about opportunities, and also to let them see we’re having fun, that there are jobs in the world where you get paid to do what you find interesting." Despite the theatrics, he adds, the coil itself is not that dangerous: "I’d just as soon not get hit by it, but I wouldn’t be afraid to get hit by it." From Schalk’s standpoint, the two-day stint at the Maker Faire was a big success. A lot of people came up after the demonstrations to sign up for SLAC tours, find out how to bring the Tesla coil to their school or ask about summer programs for their kids. The Faire itself was icing on the cake—the perfect venue for a guy who, as an undergraduate, helped three friends build a working 1.5 MeV cyclotron from scratch. "This whole show was a geek’s paradise," Schalk says. "It was eye candy everywhere. I was drooling all over the LEGO train apparatus, and all over the 3D printers that make things out of sugar." Sports car treatment for cavities Radiofrequency cavities create the electromagnetic fields that accelerate particles in a collider. The performance of the cavities, measured by the way electrons pass through them, is determined by their shape and the way they’re put together. Hydroforming starts with a niobium tube 150 millimeters in diameter. First the tube is grooved to produce the narrow parts between the cavity’s bulging cells. Then it’s filled to the brim with water. A hydraulic system increases the water pressure inside the tube, forcing the metal into a mold in the shape of the cavity. The finished product has walls of uniform thickness and only two seams, reducing the risk of welding flaws that can hinder cavity performance. "We have tried many different procedures, used all sorts of tubes, simulated every eventuality until we found the perfect way," says Waldemar Singer, a material scientist at DESY. The team had a lot of support and help from the Russian Institute for Nuclear Research. Other labs are also getting in on the act; Japan’s KEK is building
a hydroforming machine and Fermilab is planning a similar facility.
Those pesky humans The measurements are part of an experiment called EXO (the Enriched Xenon Observatory), destined for installation half a mile below ground in a New Mexico salt mine. There it will search for signs of a nuclear decay known as the neutrinoless double beta decay that researchers hope will help them pin down the mass of the neutrino. While the experiment’s deep location protects it from cosmic rays, it still has to contend with the constant chatter of natural radiation from surrounding rock and from pieces of the detector itself. To measure this background radiation, Andreas Piepke and his team have been carefully cataloging the radiation signatures of EXO’s plastic knobs, gaskets, and other components. How sensitive is the measurement equipment? The researchers had to shield the apparatus from radiation given off by their own bodies. For a typical adult, that’s about 7000 becquerels—a unit that has replaced the curie as a measure of radioactivity. In comparison, a household smoke detector contains about 30,000 becquerels, and typical low-level radioactive waste about a million becquerels per kilogram. The team also had to account for the faint radiation signatures of lead bricks used to shield the components during testing. Once all the sources of background radiation have been identified it will be easier to separate the valid signals from the noise.
Farmers’ picnic In May, the 10th annual Fermilab Farmers’ Picnic attracted nearly 100 people to celebrate their decades-old farming community. "I come back every year to see old friends," Baumann says. "We are all farmers. We’re older than rocks." Baumann will be 85 in two weeks. Inside Fermilab’s Kuhn Barn, one of several barns still in use, visitors were treated to a spread of treats, including a farm-scene cake complete with a barn and rows of crops. Fermilab’s Bob Lootens, who used to live on one of the farms, drove a group of about 10 partygoers around the lab. "I’m going to take you down memory lane," he said as the bus turned onto Holter Road inside the Tevatron’s main ring. Prairie burns have thinned out the forest, making it look as it did in the past; even the same gravel roads are there. "It’s like a time capsule," Lootens says. For the farming community, the Farmers’ Picnic is a chance to reconnect with those who used to live here. Baumann looks up his friends every once in a while, and depended on them when he had open heart surgery. "They were there to support me," he said. Flanked by relatives, Baumann pointed out people he knew from the pre-Fermilab days, including a 96-year-old woman for whom he had baled hay when he was younger. A former babysitter, Janet L. Mish, also remembered life in the rural community. "I babysat for a lot of the people who lived on these farms. I miss these people," she said. Some from the farming community can recognize patches of grass where their barns once sat. Baumann’s barn is still standing, although it is showing signs of its nearly 100 years and may have to be torn down for reasons of safety.
A tale of dark energy According to the spires database, the first three papers to contain the words "dark energy" in the title were published in 1998: a Physical Review D article by Turner and Dragan Huterer; an article by Turner summarizing his talk at the Stromlo Symposium; and a Lawrence Krauss article in the proceedings of the 1998 conference on Weak and Electromagnetic Interactions in Nuclei (WEIN 98). Since then, the number of papers has increased dramatically, often doubling or even tripling from year to year. In 2006, the number of papers with "dark energy" in the title exceeded 300 (see graphic), about 20 percent more than those published in 2005. Dark energy has captured the imaginations of physicists working in a variety of subfields represented in the spires database. While the majority of dark-energy-titled papers, about three quarters, are submitted to the spires astrophysics phenomenology (astro-ph) e-print archive, 1 in 10 can be found in gravity-quantum cosmology (gr-qc), another 10 percent in high-energy physics theory (hep-th) and 6 percent in high-energy physics phenomenology (hep-ph). Even the condensed matter physics (cond-mat) archive contains a paper with "dark energy" in its title. Today, there are more than 1000 of these papers on dark energy. A look at the references these papers make to other scientific studies reveals what might be the most influential paper in dark energy research: about one-third of all papers cite "Cosmological Consequences of a Rolling Homogeneous Scalar Field," published by Bharat Ratra and P.J.E. Peebles of Princeton University (Phys. Rev. D 37:3406, 1988).
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