Science: Bigger Mini-Bangs for the Buck

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A powerful new machine accelerates U.S. high-energy physics

As they watched a green line edge across a video screen, the excitement mounted. "It's going!" exclaimed one of the exultant scientists. "Keep going! Keep going!" shouted another. The control room soon erupted into a chorus of unrestrained cheers. Bottles of champagne were broken out, and toasts resounded.

That tumultuous scene last week, reminiscent of a locker-room victory celebration, marked a more esoteric kind of triumph. When the green line made its telltale movement at the Fermi National Accelerator Laboratory, the sprawling high-energy physics research center outside Chicago, it signified a major scientific achievement. At that instant, Fermilab's newly rebuilt accelerator (physicists prefer that term to atom smasher) climbed to 512 billion electron volts (GeV),* the highest energy level ever reached by the powerful machines used by physicists to study the fundamental secrets of matter.

The record, to be sure, was only a minor increase over Fermilab's existing capability. In 1976, five years after its completion, the accelerator hit 500 GeV and has been operating close to that level ever since. But the jubilant scientists nonetheless had reason to celebrate. The test meant that years of work had finally paid off and that the $130 million set aside to make the machine the most complex accelerator ever built had really been well spent. In the months ahead, it will gradually be boosted to 800 GeV and perhaps by next year to a trillion electron volts (TeV). At full operating power, the device will not only live up to its name, Tevatron (from the Greek teras, or monster, a scientific symbol for a trillion), but will also put the U.S. back in the forefront of high-energy physics. Says Fermilab Director Leon Lederman: "The Tevatron is a leapfrog. If we hadn't done it, our program would have been seriously compromised."

The ancient Greeks needed only their powerful intellects and imaginations to postulate atoms as the basic building blocks of matter. Today, more than ever before, such exploration requires complicated machines like Fermilab's Tevatron. By pummeling the nucleus, the atom's central mass, with protons or other subatomic particles, physicists can literally tear apart the fabric of matter, somewhat like peeling layers from an onion. Every peel, however, requires increasingly powerful and costlier machines. As Stanford Physicist Wolfgang Panofsky notes, "The smaller the objects, the bigger the microscope we must use to see them."

The findings at the other end of those searching instruments have excited the entire scientific world. In the past four years, Fermilab's major overseas rivals, notably CERN (the European Organization for Nuclear Research), located outside Geneva, have discovered a group of new particles that helps confirm what physicists call the standard model. This divides matter into two basic types of particles: quarks, which are the building blocks of protons, neutrons and other "heavy" components of the atomic nucleus; and leptons, exemplified by "light" particles like the electron.