Ssc: Lord of the Rings

When President Reagan formally endorsed the superconducting supercollider (SSC) last January, it seemed likely that the $4.4 billion, 53-mile- circumferen ce particle accelerator would be completed on schedule in 1996. But the recent breakthroughs in superconductivity have raised some questions about the 10,000 powerful magnets needed to keep streams of protons on course as they speed around the huge ring.

Should SSC designers move ahead with plans to use conventional, low- temperature superconducting magnets, known quantities that are already in place and operating at Fermilab's Tevatron accelerator in Batavia, Ill.? Or should they hold off indefinitely, awaiting development of the new high- temperature superconducting variety, which may someday be able to generate even stronger magnetic fields at less cost?

Some scientists, particularly those opposed to the SSC for other reasons, have expressed concern that the rapid developments in superconductivity could warrant a redesign of the accelerator. "It might be possible to shrink the radius down to ten miles," says Cornell Physicist James Krumhansl, president- elect of the American Physical Society. "What I say is, let's put the matter into one more year of research and development and review it next year."

Still, it is not at all certain that the new ceramic superconductors will ever be capable of carrying the high electric currents necessary for generating strong magnetic fields. And no one has yet fashioned the inherently brittle material into a wire flexible enough to be wound into effective coils, though many research groups have reported progress. Says Burton Richter, director of the Stanford Linear Accelerator Center: "It took 25 years to turn the present superconductors from a laboratory curiosity into something that could be made into miles of cable. These are even more difficult materials to work with."

Leon Lederman, director of Fermilab, agrees. "Even if, miracle of miracles, in the next two years they solve all the problems of brittleness and high current," he says, "we would still need lots of experience to understand the materials well enough to make good magnets. A superconducting accelerator magnet is a Swiss watch of precision." One problem: superconducting magnetic fields are so strong they can actually deform the accelerator magnets that produce them. While physicists have learned to deal with that phenomenon at Fermilab, they have no idea how to handle fields that could be many times as strong.

Proponents of delay, Lederman charges, are more concerned about the tremendous cost of the SSC, which they think will siphon federal funds away from other branches of science: "They see the new superconductors as a weapon with which to slay the SSC."

Krumhansl excludes himself from that category. "It would be wrong to say I'm against the SSC," he says. "It's great scientifically. In fact, it's mind blowing. The problem is that over the past five years there has been a slow starvation of what I call 'small science.' I say first get small science in good shape, and then by all means proceed with the SSC."