Super-cool superconductors

From left: Allen Rusy, Tom Van Raes, Vito Lombardo and Daniele Turrioni make up the Fermilab Superconducting Research and Development Group, led by Emanuela Barzi.

Tom Van Raes stands behind his workbench in TD's Industrial Center building, surveying a six-foot-long cylindrical piece of metal wrapped with plastic and fitted into a vice. Pointing out the fine wires that wrap around a small tube in his hand, he demonstrates where the piece fits on the probe. "There aren't classes to learn how to do this," he says.

Van Raes is one of five members of the Superconductor Research and Development Group who test materials that redefine superconductivity. Superconductors can be everyday metals like aluminum, but when cooled below a critical temperature, their resistance drops suddenly to zero. The tiny wires on Van Raes' tube wind together to make cables hundreds of meters long and form huge magnets that bend high-energy beams and make particle colliders possible.

Led by Emanuela Barzi, the group tests the wires by mounting them on a probe and immersing them in a liquid helium cryostat the size of a large home furnace. After cooling the material -- typically a niobium-tin compound -- they measure its current at various magnetic fields. The goal is to increase the field beyond that presently required to operate the LHC, while maintaining high currents, said Daniele Turrioni, the group's lead engineer. Turrioni wrote the lab's data acquisition programs and supervised graduate student Vito Lombardo in his engineering thesis. The team serves the LHC Accelerator Research Program, the High Intensity Neutrino Source, and the ILC, and their research helps manufacturers improve their superconductor performance.

Barzi says she loves the thrill of seeing applied results. "Superconductivity is an interface field," she said. "It's a perfect field to apply both engineering and physics."

Last year, the Director's Review of the Fermilab high field superconducting magnet program recognized the group as having the broadest and largest test capability of any U.S. laboratory. The group is most excited about a new probe, assembled by group administrator Allen Rusy, that would allow them to test whole superconducting cables at once. They hope to have a portion of the new probe finished this week. "It will make us the largest cable testing facility ever," said Barzi.

--Christine Buckley

Scientific American
April 12, 2007:

The Standard Model of particle physics emerges unscathed-for now

The first results from a long anticipated experiment have heaped doubt on decade-old observations that hinted at the existence of a fourth type of neutrino, a ghostly particle that rarely interacts with ordinary matter. Researchers from the MiniBooNE experiment at the Fermi National Accelerator Laboratory in Batavia, Ill., announced the finding yesterday.

Confirmation of the fourth neutrino would have given researchers a sign that something was wrong with their highly successful Standard Model, which describes the known particles. "We've all been waiting on pins and needles," says neutrino physicist Edward Kearns of Boston University, who works on other neutrino experiments. Seeing something new is always more exciting, he says, but "it's just extremely important that we get this out of the way and focus on other ideas."

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