The Advanced Light Source (ALS) of the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) has received a unanimous endorsement from a prestigious review panel appointed by DOE's Basic Energy Sciences Advisory Committee (BESAC).

Citing the prompt response of Berkeley Lab management to the criticisms of an earlier BESAC review panel, the elevation of the ALS to divisional status and the appointment of prominent materials scientist Daniel Chemla to head it, plus improved interactions with its users, its scientific advisory committee and the University of California, the BESAC review panel recommended that any penalties imposed on the synchrotron facility be lifted and there be no further reviews in the near future.

"It is clear that the ALS is doing an outstanding job in many areas and that none of the criticisms of (the earlier review) are still valid," declared Yves Petroff, chair of this latest review and Director General of the European Synchrotron Radiation Facility. Petroff and his panel presented their report to BESAC in a meeting in Gaithersburg, Maryland on February 28.

The ALS is an electron synchrotron designed to accelerate electrons to energies of 1.5 billion electron volts (GeV) and extract from them -- using either bending, wiggler, or undulator magnetic devices -- premier beams of ultraviolet and low energy or "soft" x-ray light. As one of DOE's designated "national user facilities" it is available to qualified researchers throughout the United States.

In 1997, a BESAC review panel of DOE's synchrotron light sources chaired by Robert J. Birgeneau of the Massachusetts Institute of Technology, made the ALS a low priority in its recommendations based on several criticisms. The new report panel chaired by Petroff praised Berkeley Lab management for "reacting very quickly to the criticism," which the new panel found only "partly justified."

In reviewing the technological capabilities of the ALS itself, the Petroff report credited the ALS with having "the lowest horizontal emittance in the world" for synchrotron light sources at below 2 GeV energies and for being "very reliable" with an availability rating of 95 percent. Of the scheduled installation of superconducting bend magnets in the storage ring, the report said this upgrade will "enhance considerably the capacity of the facility."

A major thrust of the Petroff report was the quality of science at the ALS. "Areas of excellence" were cited in structural biology; femtosecond and picosecond dynamics in condensed matter and gas phases; electronic properties in superconductors and magnetic nanostructures; surface science, thin films and x-ray microscopy; ultra-high resolution spectroscopy of gas phase atoms, ions and molecules; nanoscale chemistry, biochemistry and catalysis; and analytical sciences and metrology.

The Petroff report also expressed "strong support" for upcoming projects that include molecular environment science, magnetic and polymer nanostructure research, and femtosecond spectroscopy and diffraction.

"We believe that in the area of femtosecond spectroscopy and diffraction, the ALS is in a unique position," said Petroff. "It is the only center in the world able to produce 100 femtosecond slices (a femtosecond is a millionth of a billionth of a second) of light."

The combination of the ALS with a femtosecond laser, said the Petroff panel, positions Berkeley Lab to be a "world leader for many years to come" in the study of ultrafast chemical reactions, phase transitions, surface dynamics and a wide range of critical biological processes that operate on the sub-picosecond timescale. The long-time dream of direct x-ray experiments on this timescale should also be realized.

Much of the criticism of the earlier Birgeneau report focused on frustrations expressed by ALS users outside of Berkeley Lab. The Petroff report notes that the number of ALS users has tripled since the Birgeneau report and that these users were "very pleased" with the appointment of Chemla to direct the facility. (Since opening in 1993, the ALS has been used by more than 500 scientific groups.) Under Chemla's leadership, the report said, the ALS management and the user community have established "productive, respectful and direct two-way communication."

The Petroff report recommended that DOE increase the size of the ALS scientific support group, fund more post-doctoral associates, and support the ALS plan to have a new building adjacent to the facility to provide more office space for the users and additional laboratories for sample preparation and experimental staging.

Members of BESAC unanimously accepted the Petroff report and its recommendations.

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California.

Additional Information:

• Femtosecond pulses generated at Advanced Light Source
• Let There Be Light (from the Fall 1998 Research Review magazine)
• Advanced Light Source Web site