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In this issue:
From the Director: Now the Fun Begins!
First Test of New X-ray Laser Strips Neon Bare
Don't Sweat the Heat—Cooling Tower Work Moved Back
Added Spam Scanning
Word of the Week: Synchrotron

SLAC Today

Friday - September 18, 2009

From the Director: Now the Fun Begins!

(Photo - Persis Drell)
(Photo by Linda Cicero.)

The Linac Coherent Light Source achieved another major milestone last weekend as the first experiment, the Atomic, Molecular and Optical instrument, took its first test data. (See " First Test of New X-ray Laser Strips Neon Bare," below.) It may sound easy... just get the LCLS beam into the first experimental hutch and onto a target… But that objective translates into a huge amount of work, carried out over that past three-and-a-half years, with the last six months being brutally intense.

Lots of parts had to work all at the same time: diagnostics, focusing optics (constructed at Lawrence Berkeley National Laboratory), the gas target, vacuum chambers and a whole host of detectors. Saturday morning, September 12, for the first time, it all came together.

The exercising of the AMO instrument this week confirms that the experimental station is ready for first scientific research. This is the result of a lot of hard labor by John Bozek, Christoph Bostedt, Jean-Charles Castagna and the other physicists and engineers who put the instrument on the floor. This crew has truly been working round the clock. Their announcement of the weekend’s success was met with well-deserved applause at the Monday 8 a.m. LCLS meeting in the Main Control Center.

Throughout the commissioning of the AMO instrument, the LCLS X-ray laser has worked stably and reliably. The AMO commissioning team was particularly pleased with the accelerator operators' ability to control the X-ray energy in response to their requests.

LCLS is ready to deliver beam to its first users in less than two weeks. Now the fun begins!

First Test of New X-ray Laser Strips Neon Bare

(Photo - AMO instrument moved into its experimental hutch last June)
The main experimental chamber of the AMO instrument, the high-field physics end-station. Here, a gas jet sends pulses of sample gas into the chamber where it will be ionized by X-rays from the LCLS. The results are detected by several spectrometers arrayed around the central interaction region. Read more in the AMO Technical Specifications. (Image: SLAC Infomedia Solutions.)

It takes a lot of energy to strip all ten electrons from an atom of neon. Doing it from the inside out, knocking away the most-closely-held, innermost electrons first, is an even rarer feat. But the brilliant X-ray pulses of the Linac Coherent Light Source have done just that, in the successful first test of the unprecedented X-ray laser with its first scientific instrument. The result demonstrates the machine's unique capabilities—with the world's brightest and shortest X-ray laser pulses—and marks the first of two milestones in readiness for the launch of LCLS scientific user experiments this October.

Early on September 12, scientists at the Department of Energy's SLAC National Accelerator Laboratory introduced puffs of neon gas into the sample chamber of the LCLS Atomic, Molecular and Optical science instrument. The AMO instrument's ion detector picked up showers of positively-charged neon nuclei—where the charge indicates the number of missing electrons—ranging from partially to fully ionized. The scientists were able to adjust the proportion of different neon species, from non-ionized Ne (no missing electrons) to Ne10+, lacking all 10 electrons, by fine-tuning the powerful LCLS X-ray beam.

"This truly shows we're reaching a new regime with the LCLS, to access physics that's never been available before," said instrument scientist John Bozek, who has spent the past 3.5 years planning and developing the AMO instrument.  Read more...

Don't Sweat the Heat

Cooling Tower Work Moved Back

The Cooling Tower 101 replacement project has been postponed. There will be no interruption of cooling to SLAC buildings in the coming weeks. The project will resume this fall/winter. Keep an eye on SLAC Today for updates.

Added Spam Scanning

As of Monday, September 21, SLAC will be scanning outgoing e-mail for spam. If a message is found to be spam with a rating of 90 percent or higher, the SLAC sender will be notified immediately (via a bounce message) that the outgoing message was rejected. The bounce message will tell the sender the intended recipients and subject line of the bounced message.

SLAC's Enterprise Applications team is implementing these changes in an effort to prevent SLAC from being a source of a spam outbreak due to stolen account credentials. If credentials are stolen, then the spammers can use our central email servers. SLAC Computer Security has had tools to detect spam-bots (lots of outgoing emails) on individual user computers for some time, but this doesn't help if the spam is coming from SLAC's central e-mail servers.

The filtering will start with a conservative level of 90 percent spam rating but may lower that at some time in the future.

If you have any questions about this change, please send them to

(Image - video Word of the Week: Synchrotron)
Video by Brad Plummer and Nicholas Bock (time 1:33). You can also download the video file as a low resolution (10 MB) or high resolution (40 MB) QuickTime file.

of the Week: Synchrotron

Synchrotrons are circular particle accelerators that are a key tool for scientists investigating the realm of the ultra small. Science writer Nicholas Bock explains in this video installment of the Word of the Week.


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