Physics @ Berkeley
Physics in the News
Title: Brightening Science's Future
Date: 11/27/2007
Publication: Science Matters @ Berkeley
Extended Text:

The minute you opened your eyes this morning, the curtain of pigments at the back of your eye began changing at a breakneck pace. Every photon that hits your rods and cones twists those pigments into new and temporary shapes. It is these new shapes, or isomers, that ultimately generate the sensation of vision in your brain.

According to Berkeley physics professor Roger Falcone, ultrafast processes like those underlying vision are everywhere: plants performing photosynthesis, hemoglobin shuttling oxygen to your cells, sunlight converting pollutants into smog. "Most chemical reactions have many fast and complicated steps in between, and those are what we're trying to unravel," Falcone says.

To observe these brief phenomena, Falcone uses the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. Housed in a cavernous circular building high above campus, this machine produces beams of x-ray light a billion times brighter than radiation from the sun.

Together with a team of scientists and engineers at the ALS, including his colleague Robert Schoenlein, Falcone helped develop an instrument that converts x-rays from the ALS into extremely rapid bursts. Just as a strobe light freezes a pitcher's high-speed throw into a series of incremental movements, these x-ray pulses can capture fleeting events in the movements of two passing molecules. These snapshots can illuminate the steps within the fastest chemical reactions.

Falcone became director of the ALS last year. His primary job at the light source is to enable the more than 2,000 researchers who visit the lab each year from around the world to conduct their experiments smoothly. Their ALS projects range from visualizing protein structures via x-ray crystallography, to analyzing the chemical composition of dust from the 9/11 World Trade Center disaster.

Falcone is also helping to lay the groundwork for a next-generation light source at the lab. Envisioned to be the most powerful x-ray light source in the world, the new instrument could take as long as ten years and cost as much as $1 billion to complete.

The Advanced Light Source, the circular building at center.

The current light source at the ALS can image the structure and bonds of almost any material and observe the motions of molecules. The new instrument, an x-ray free electron laser, could resolve how clouds of electrons-the glue that binds atoms and molecules together- adjust in the instant before a chemical reaction or a change in the structure of a solid, such as melting. By allowing scientists to observe such events, which occur at orders of magnitude shorter than can be visualized with the present light source, the new machine, says Falcone, "would take the tools to observe nature's pathways, microscopically, to a whole new level."

With this new instrument, scientists could test the computer simulation models they use to predict the behaviors of countless enzymes and nanomaterials, evaluate and refine the performance of chemical catalysts, and even observe why atoms in superconductors produce capabilities that are more than the sum of their parts.

Although the ALS occupies most of Falcone's time, he remains involved in undergraduate education. Falcone is a faculty co-director and instructor for Cal Teach, a UC-wide effort to encourage undergraduates in math and science to become K-12 teachers in these fields. Cal Teach students complete their normal undergraduate course requirements while taking additional courses that provide training in education. Upon graduation, the students will be eligible for an intern teaching credential.

Falcone believes Cal Teach also fulfills a need on campus for what he calls "pre-ed." He says, "We have very clear pre-med and pre-law programs on campus, with associated student organizations, clear course requirements, and faculty advisers. But there hasn't been a commensurate program where people can tell you what courses to take to become a teacher. CalTeach is a parallel pre-ed program with the goal of allowing students to get jobs as teachers right after earning their bachelor's degree."

Falcone views the research and teaching aspects of his work as supporting the University's scholarship goal. He says, "Whether you're a student searching for skills or insights in a field, or a researcher investigating brand new concepts, it's all about the same goal-the search for knowledge."

Related Web Sites