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In this issue:
From the Director of the Stanford Synchrotron Radiation Lightsource: Timeless SSRL
Quantum Diaries Are Back
Welcome new SLACers!
Word of the Week: Fluorescence

SLAC Today

Friday - April 3, 2009

From the Director of the Stanford Synchrotron Radiation Lightsource: Timeless SSRL

(Photo - Joe Storh)

In my last SLAC Today column, I wrote about the history of the Stanford Synchrotron Radiation Laboratory and how it fits into the bigger model of "one lab." In the meantime, SSRL changed its name from "Laboratory," which now appears in the SLAC name, to the more appropriate "Lightsource." Today I want to update you on how this 35-plus-year-old lightsource manages to keep up with the best in the world. No doubt, SSRL has stiff competition: the Web site now lists nearly 70 lightsources worldwide. Here is the story of how through the years SSRL has kept its place in the elite club of facilities that can count themselves as "top notch" in terms of brilliant X-rays, number of users and scientific achievements.

In terms of spectral brightness, a metric that best characterizes the quality of an X-ray source, SSRL's SPEAR3 is an excellent source; yet newer ones just commissioned or under construction have edged ahead with time. Fortunately, however, source brightness is only part of the story in lightsource quality. Given that the performance of our source is sufficiently close to the best, other factors can move us ahead on the path to scientific excellence. The secret of SSRL's success has been to squeeze the most out of what is there. Tight operations budgets and understaffing, especially over the last two years, have been overcome by the ability of SSRL staff to tighten their belts, stretch their responsibilities and go the extra mile in support of the user program. Another factor is the quality of the SSRL scientific staff, which always receives special mention during external reviews. Many of our scientists carry out their own scientific programs, performing experiments not only at SSRL but if needed also at other synchrotron radiation facilities. In the end, they bring back to SSRL what they have seen and learned, and this is incorporated into the SSRL program.  Read more...

(Image - the Quantum Diaries home page)

Quantum Diaries Are Back

Are physicists' models being held culpable in the financial meltdown? Do physicists appreciate music for its mathematical appeal? How will the International Linear Collider complement the Large Hadron Collider? These topics and more are under discussion in the blogs of Quantum Diaries, freshly launched yesterday with a new set of visiting contributors from around the globe and across the world of particle physics.

"I certainly jumped on the opportunity to communicate my life, my science and the ideas I'm really interested in," said Quantum Diaries blogger Nicole Ackerman, a Stanford graduate student working on the Enriched Xenon Observatory at SLAC. "I really like the chance to share with the science community, but also the non-science community who are interested in the science."

First online during the World Year of Physics in 2005, Quantum Diaries is sponsored by an international group of particle physics laboratories through the InterAction Collaboration. Participating diarists volunteer for three-month stints sharing their work and daily lives through bios, videos, photos and blogs. Interested, potential bloggers working in particle physics are encouraged to contact SLAC communicator and Symmetry magazine Editor-in-Chief David Harris.

Topics are open to the diarists' imaginations and perspectives. "I'm interested in intersections between physics and other things," Ackerman said. Among her first posts are discussions of two-career academic couples and bicycling physicists, alongside an article on her work studying neutrinos. "This is a way of communicating with a larger group when I read a really interesting book or see a great Web site, or just make some observations." And the conversation goes both ways.

"Since it's a blog, people can write comments and share their stories," Ackerman said. "I can start that dialog [with a blog post], then it can involve other scientists from all over the world."

For more about the new particle physics blogs, see the Quantum Diaries news release.

Welcome New SLACers

(Photo by Doug Kreitz.)

New SLAC staff attending yesterday's new employee orientation included:

Back row, from left:
Henia Kamil, Jason Tiller, Bryon Engelhardt, Shannon Reed and William Olson

Front row (seated):
Sherrie Remington, Jerry King and Marcia Torres.

Welcome to SLAC!

(Photo - two scientists place a fossil into an X-ray hutch at SSRL)
Paleontologists Sam Farrar and Peter Larson move the Archaeopteryx fossil into an experimental hutch for X-ray fluorescence studies at SSRL. (Photo by Brad Plummer.)

Word of the Week: Fluorescence

In 1852, British physicist George Stokes coined the term "fluorescence" to describe the strange glow he observed when he exposed the mineral fluorspar to ultraviolet light. Now the word refers to radiation some materials emit after exposure to relatively higher-energy radiation. Fluorescent lighting is a familiar example of this phenomenon in action. Turning on a fluorescent light causes a small amount of mercury vapor within the tube to emit ultraviolet radiation. The tube's phosphor coating absorbs this UV light, then shines in the comparatively lower-energy visible spectrum. At the Stanford Synchrotron Radiation Lightsource, scientists can study materials by bombarding them with high-energy X-rays and looking at the lower-energy X-rays they emit. This technique is called X-ray fluorescence.

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