SPEAR3 Pierces Brightly

The latest incarnation of the Stanford Positron Electron Asymmetric Ring was unveiled on 29 January. A hefty beefing up of a machine that began life as a particle collider more than 30 years ago led to SPEAR3, a top-of-the-line x-ray radiation source for intermediate energies (500–15000 eV), says director Keith Hodgson.

SPEAR3 can accommodate more users than its predecessor. More important “is what the increased brightness buys you—improved spatial resolution,” Hodgson says. “You can focus the x-ray beam down to micron dimensions and have enough photons to do chemical speciation, surface scattering, protein crystallography.”

“This new facility exemplifies the collaborative nature of science and the productive cross-fertilization between biological and physical disciplines,” Elias Zerhouni, chief of the National Institutes of Health, said in a statement he prepared for the dedication of SPEAR3. NIH and the US Department of Energy jointly footed the $58 million upgrade tab. “For a relatively modest investment, we have gained a formidable light source,” says Hodgson. The upgrade was completed in less than a year.

Also in January, the San Francisco-based Gordon and Betty Moore Foundation announced a $14.2 million gift to Caltech, most of which will be used to build a beam line at SPEAR3 for remote-controlled studies in structural molecular biology.