PRISM Magazine Online - May-June 2000
Where Matter Matters Most
After Congress pulled the plug on the U.S. supercollider, a massive lab tucked away in Switzerland became the world's focal point for particle physics.

By Thomas K. Grose

At the Conseil European pour la Recherche Nucleaire, the really interesting bits are hidden by beautiful scenery.

The lab, popularly known as CERN, resembles an Alpine tech college, circa the mid-1950s. It's a collection of drab office buildings set on nearly 1,500 acres of otherwise bucolic landscape just outside of Geneva, at the Swiss-French border. The Jura Mountains, a few miles--and several picturesque hamlets--away, provide a majestic, snow-capped backdrop. And the campus is swathed by vast expanses of sheep-grazed farmland.

But 263 feet below ground, CERN's Heidi-goes-to-college setting is quickly forgotten amid an engineering netherworld of huge electromagnets, massive machines, and endless cement tunnels. This is the home of Europe's particle physics laboratory, where state-of-the-art big science attempts to discover what matter is made of and how it's glued together. Toward that goal, scientists blast beams of subatomic particles through two circular tunnels known as accelerators. The particles are raced at nearly the speed of light and crashed into one another--40 million collisions occur per second--or into stationary targets, in hopes of breaking them down to their smallest components. Because these collisions--some of which attempt to replicate in miniature the origin of the universe, the big bang, and reach temperatures 100,000 times hotter than the sun--occur so rapidly and minutely, specially designed detectors are deployed to make them "visible." "This," says Peter Denes, a Princeton University research physicist who has spent 15 years at CERN, "is the energy frontier."

And, since Congress pulled the plug seven years ago on the 56-mile-around Superconducting Supercollider (SSC) in Texas, the 46-year-old CERN lab has also become the world's focal point for particle physics. "We've been raised from the flames of the SSC," says Roger J. Cashmore, CERN director of research. Denes agrees: "A lot of people who were involved with the SSC transferred wholesale to here." During the course of a year, around 7,000 physicists from around the globe come to CERN to work. Currently, 3,600 physicists are working on two different projects at the Large Hadron Collider (LHC), now under construction, and about 20 percent of those scientists are American. "The United States is the single biggest national user   community," Cashmore explains. "Americans represent an enormous presence here, and a good one, too."

This kind of mega-science--detectors are as large as a four-story building and experiments can last for years--doesn't come cheap. CERN's annual budget, paid by the 20 member states, $626 million. And construction of the LHC, which goes online in five years, will cost $1.93 billion, of which the U.S. will contribute $531million, mostly from the coffers of the Department of Energy and the National Science Foundation. The LHC will represent the next generation of particle-physics colliders. It will allow 800 million collisions per second to occur, at impacts 35 times more powerful than those now created here.

Areas of Inquiry

To discuss the two major probes conducted at CERN, it helps to review some basic physics. Atoms are composed of protons and neutrons. Their building blocks are "up quarks" and "down quarks," which are held together by gluons. A positively charged proton consists of two up quarks and a down quark. A negatively charged neutron consistscooled and gelled, and quarks and gluons formed neutrons and protons, eventually becoming suns, planets, and all other forms of life and matter. The expectation is that, if the particles are smashed together powerfully enough, the impact will free the quarks from their gluon chains. At least momentarily.

Toward that goal, CERN's scientists in February announced that, using the nuclei of lead atoms in the SPS, they had "compelling evidence for the existence of a new state of matter in which quarks . . . are liberated to roam freely." What their detectors saw, they said, can't truly be called a quark-gluon plasma, because the evidence is circumstantial. It "resembles a jigsaw
 puzzle, with many pieces provided by the different experiments" which "is not enough to give the full picture, but the combined results from all experiments agree and fit . . . and are consistent with the predicted signatures of a quark-gluon plasma."

Many particle physicists outside of CERN welcomed that tantalizing morsel of news, but cautioned that the Swiss lab's explanation may have been a bit over-cooked. The effort to create a true quark-gluon soup now passes to the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory in New York. "Those of us working on RHIC are very encouraged by [CERN's] results," Thomas Ludlam, the lab's senior scientist, told The Washington Post. This summer, the $600 million Brookhaven collider will begin bashing gold nuclei in collisions 10 times more powerful than those that CERN can currently muster. But the focus will return to CERN in five years, once the even more powerful LHC--which will also use the LEP's 17-mile track--is up and running.

"Accelerators do have sell-by dates," Cashmore says, referring to their shelf-life. Cashmore, who joined CERN earlier this year from Oxford University, notes that the initial accelerator here, the proton synchrotron, was built in the 1950s. The SPS debuted in the 1970s, using the beam from the original accelerator. And the SPS's beams will be injected into the upcoming LHC. Particle physics may be expensive, but its practitioners are frugal. "You don't just throw away the old investment, you incorporate it into the next step," Cashmore says. It appears that CERN has attempted to husband some of its resources by skimping on building maintenance. Oh, everything is very clean--this is Switzerland, after all. But its office buildings, designed in a '50s moderne style that is the architectural equivalent of the Edsel, look a bit tattered at the edges. In many ways, CERN is a small city that's not only home to thousands of scientists, but employs or contracts 4,000 staff members, including engineers, builders, and administrators. "This is a community that never sleeps," says spokesman Neil Calder. Even at 4 a.m., you're likely to see hundreds of people still at work, so plenty of services are needed to keep them happy. The central building houses a bank, restaurant, and post office, and there's a hotel on campus. There is even a ski lift that can transport someone from CERN to a Jura ski run within 30 minutes.

The collegiate feel of CERN is enhanced by its strong links to many of the world's great research universities. "Education is important to us, but we are not a university," Cashmore explains. That said, CERN functions in many ways like a graduate school. It has graduate- program links to most of Europe's research schools and about 200 grad students receive their diplomas or doctorates each year--in fields ranging from physics to engineering to athematics--based on work carried out at CERN. Moreover, it awards 90 two-year fellowships each year for research in such areas as experimental or theoretical physics, engineering, and applied sciences.

Beneath the Surface

If CERN looks a bit shopworn above ground, it certainly gleams below ground, though some of the equipment is decades old. Entering the chamber of one of the main detectors is like going inside a gigantic Erector Set complex de signed by the surrealist painter, M.C. Escher. It is a maze of big electrical machines, steel ladders and catwalks, huge pipes, and thick ropes of wiring going every which way. At the heart of the chamber, ringing the tunnel, is a huge, red electromagnet, built in the former Soviet Union. Indeed, the detector is an amalgam of equipment and parts coming from all over the world and it clearly is a testament to the engineers' art. From floor to roof, the chamber is 70 feet high. And it seems ironic that it takes equipment so enormous to measure activity so minute.

The LEP's tunnel also has an unworldly atmosphere. The beam itself runs through a railing-like grid that's completely housed by magnets, and it takes up only a small portion of the tunnel. Workers and scientists glide around the tunnel via a small monorail system, or on electric carts. So monotonous is the tunnel that maintenance workers have crashed carts after being lulled to sleep after a few miles of travel.

CERN's accelerators are in almost nonstop operation from April to November. The rationale behind the winter break is twofold: Electricity is more expensive during winter, and power outages more likely. The down time is used as a maintenance period. And it's usually the plumbing, for the system's cooling system, that's most in need of repairs. "It's always springing leaks," Calder says. Despite the stolid, heavy industrial look to the complex, this is very sensitive gear. For instance, lunar phases have to be programmed into the accelerators because the moon's gravitational pull fractionally alters the size of the Earth, which can throw off measurements.

Construction of the LHC, at least the digging of the hole that will house it, has begun, even though the final design remains a work in progress. The high-velocity collisions it will create as part of the hunt for the Higgs boson are the result of cutting-edge science. "But the price to be paid is the creation of a lot of radioactivity," Denes admits. Current experiments at CERN create little, if any, radioactivity. Safely handling the LHC's radioactivity "is a technological challenge" that's almost, but not fully, solved. Because of these design hurdles, Denes adds, he often feels more like an engineer than a physicist.

The work at CERN is pure, fundamental research, with no sure results nor destinations known. Discoveries, when they come, provide more questions than answers. Given the high cost, invariably it's asked what practical outcome this research will yield. Physicists tend then to talk of spinoffs from the technologies developed to do this sort of work. Many have already been put to practical use. CERN's most famous byproduct is the Internet. It was developed here to let far-flung particle physicists communicate at length and share voluminous documents. While understandably proud of that achievement, CERN has never earned a penny from it, which often surprises people. Cashmore argues, "If we had [patented it], it probably wouldn't have taken off. It took off because it was free." Also, many diagnostic tools used in medicine and industry were born in particle-physics labs. The most famous example is magnetic resonance imaging, now commonplace equipment in hospitals.

But what applications will enrich humankind once scientists successfully cook up a hot soup of quarks and gluons or isolate the Higgs boson? No one knows. Yet Cashmore is fond of quoting 19th century British scientist Michael Faraday, whose discoveries harnessed electricity. When asked by a government minister what useful purpose electricity served, Faraday responded, "One day, sir, you may tax it." Undoubtedly, today's governments hope they'll eventually receive a similar return on their investments.

      Thomas K. Grose is a freelance writer in London.

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