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Collaborative White Paper Makes the Case for Future X-ray Sources

In December 2008, scientists from Argonne, Brookhaven, Lawrence Berkeley and SLAC national laboratories finalized a white paper titled, "Science and Technology of Future Light Sources," illustrating the scientific need for more powerful light sources.

"X-ray science can help solve some of society's challenges in areas such as health, technology, energy and the environment," said Joachim Stöhr, Director of SLAC's Stanford Synchrotron Radiation Lightsource. "We [the authors] wanted to outline the power of X-rays to answer fundamental scientific questions and prepare the path for increased funding of photon science." The authors submitted the paper to the Department of Energy's Office of Basic Energy Science, a timely input to help brief the Obama administration on this evolving field.

The 87-page white paper highlights the field's past accomplishments and present capabilities, among them the ability to "see" the invisible world of atoms. It then outlines concrete challenges from materials science, biology, chemistry, energy science and other fields that cannot be met by today's state-of-the art synchrotron radiation sources. Looking even beyond the Linac Coherent Light Source's ultrafast, ultra-powerful X-ray pulses, the paper sketches some of most promising features of tomorrow's light sources. For example, future X-ray sources could allow complete control of high-repetition X-ray pulses in space and time. This technology could enable diverse advances such as understanding high-temperature superconductivity, mapping the dynamics of energy-producing chemical reactions, or controlling biological processes on the molecular level needed for drug therapy.

The white paper emerged from a discussion between SLAC Director Persis Drell and then Lawrence Berkeley National Laboratory Director and current Secretary of Energy Steven Chu about the need for a compelling strategy for the next generation of X-ray sources. As a first step, in June of 2008, Drell and Chu asked Stöhr and LBNL Advanced Light Source Director Roger Falcone to co-chair a study group comprising photon scientists from both institutions to assess how new light sources need to perform in order to address today's most important scientific questions.

"It was a wonderful brainstorming process," Stöhr said of the intense weeks that followed. "People from LBNL and SLAC really worked together well." Argonne and Brookhaven scientists soon joined the collaboration. Knowing that the future will see individual laboratories submitting competing proposals, the group discussed the capabilities and limitations of different types of sources. But, Stöhr noted, the mood was collaborative rather than competitive. "The goal was to create a compelling vision for the entire field of X-ray science."

In the future, Stöhr says he especially wants to see his colleagues come together to take stock of the advances in accelerator research that are needed before the next generation of light sources can be built. "Parts of the technology aren't here yet," he said. "We need to understand what is required before we take the next step, and develop a plan to address potential showstoppers. Hopefully we can again create a joint vision that defines the path for future investments by DOE."

—Lauren Schenkman
SLAC Today, February 24, 2009