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Linac Coherent Light Source Overview

SLAC National Accelerator Laboratory is making "molecular movies" with the Linac Coherent Light Source (LSCLS).

As any student who has ever set foot in a middle school science class can probably tell you, atoms are the building blocks of life and an ever-present part of our existence. They make up every physical element we come in contact with and yet there are still major questions about how they form and function.

Later today, Secretary Chu will join in the dedication of a new instrument, called the Linac Coherent Light Source (LCLS), which seeks to answer many of the outstanding questions about atoms by creating “molecular movies”.

Until now, scientists typically utilized synchrotron X-ray sources to examine the behaviors of atoms. These X-rays utilize long pulses to capture the atoms but because atoms are constantly moving, this technique could only yield blurred images of their motions. This is similar to the effect that a slow shutter speed has on a photograph, since prolonged exposure time allows for items or subjects within the frame to shift often resulting in smeared, blurry looking shots.

The goal of the LCLS is to replace those blurry images with a series of precise images, that when viewed in sequence, amount to a stop-motion view of the movements and chemical bonds that make up life. Located at the SLAC National Accelerator Laboratory in Menlo Park, California, the LCLS achieves this ground-breaking level of precision by producing X-rays that are both very intense and clumped into ultrafast pulses. That’s the camera equivalent of a combining a great flash and lightening quick shutter, with a speed of less than 100 femtoseconds — which is about the same amount of time it takes light to travel the width of a human hair. To put it another way, a femtosecond is to a minute as a minute is to the age of the universe. So that is one fast shutter! Fast enough, in fact, to actually see the changes as a chemical reaction happens.

At its full potential, the LCLS will produce ultra short X-ray pulses more than a billion times brighter than any previous source — powerful enough to make detailed images showing the atomic structure of single molecules. Its unique capabilities make the LCLS a powerful tool for research that could have broad implications in a wide range of fields, including physics, chemistry, biology, materials and energy sciences. In the testing phase alone, researchers were able to use the LCLS to selectively strip electrons from the atoms that make up neon gas, in any order they chose. While that specific accomplishment may not hold any immediate implications for our daily lives, it speaks to the possibilities presented by this new instrument and gets us one step closer to understanding the intricacies of not only chemical bonds and physical matter, but of life itself.

For example, in the next few years, medical researchers may be able to use the facility to take pictures of the proteins that cause Alzheimer’s. A better understanding of the structure of these proteins could eventually help lead to better treatments or even a cure. Researchers may also be able to image and document the chemical process of photosynthesis. A better understanding of how nature turns sunlight into fuel could lead to major improvements in solar energy.

Check back tomorrow for more coverage of the dedication and Secretary Chu’s thoughts on this innovative technology. In the meantime, you can watch the video above for a step-by-step overview of the LCLS.