Batavia's Big Beam

For days, excitement had been building at the AEC's huge National Accelerator Laboratory at Batavia, Ill. Crowds of curious spectators hovered anxiously around the main control room, watching the meters and oscilloscope screens. On the screens, a narrow band of light--representing the electrical energy in a beam of speeding subatomic particles inside the atom smasher's doughnut-shaped tunnel--edged toward a telltale marking. The room became strangely silent. Then someone exclaimed, "There it is!" and wild cheering broke out.

The assembled scientists and technicians had every reason for jubilation. After many plaguing problems, the world's largest atom smasher had reached its programmed energy level of 200 billion electron volts (GeV).* That was not only the most powerful beam ever achieved by an accelerator, but also far surpassed the former record achieved by the Russians in their 76 GeV machine outside Moscow. Just back from congressional appropriations hearings in Washington, NAL'S beleaguered director, Physicist Robert R. Wilson, happily passed out champagne in goblets saved for the occasion and emblazoned with "200 GeV."

Fouled Tube. For a while, it looked as if Wilson might have to wait a long time to use those special glasses. In what turned out to be an expensive economy measure, Batavia's builders had decided not to air-condition the main tunnel of the $250 million machine. As a result, warm, humid air seeped into the tunnel last summer, and water condensed inside the coils of the 1,000 giant magnets that bend and focus the atom smasher's proton "bullets" as they race around this circular race track at speeds close to that of light. Shorted out by the moisture, some 300 magnets weighing up to twelve tons had to be repaired, resealed or replaced.

Another major headache for Wilson was caused by debris left in the 2-in.-by-5-in. vacuum tube through which the protons travel inside the tunnel; the tube must be free of dust arid debris so that the speeding protons do not prematurely lose their energy in accidental collisions. Trouble was, workmen who removed the magnets left behind metal chips and other stray objects that fouled the tube. NAL scientists briefly considered recalling the tiny ferret that had helped cleanse the accelerator's subsidiary tube systems of debris (TIME, Oct. 4). But they eventually settled on a more mundane solution: a magnetic sweeper, forced through the tunnel by air pressure, picked up the stray bits of metal.

Despite those misfortunes, Wilson managed to generate a 200 GeV beam before July 1972, the originally scheduled target date. He also stayed within budget even with the expensive magnet repairs (estimated cost: $1,000,000). Was the monumental effort really worth it? Addressing himself to that question at the congressional hearing, Wilson had no doubts. "We can say," he testified, "that we are about to complete a new scientific instrument that will allow us to see much deeper into the atom, that we know there is much yet to be seen and that the new knowledge will help us better to understand the universe--and hence ourselves."

*G stands for giga, from the Greek for giant, and is used internationally to designate a billion.

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