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In this issue:
From the Director: Workgroup Meetings
SSRL Beamline 14 Sees First Light
Word of the Week: Accelerator

SLAC Today

Friday - April 17, 2009

From the Director: Workgroup Meetings

(Photo - Persis Drell)

For the past two weeks I have been meeting with work groups across the laboratory. I try to do this every four to five months. The format is always the same. I talk for 5-10 minutes about what is on my mind and the rest of the hour is question and answer. I do my best to answer any question that is asked. Sometimes the questions are challenging but they are never unwelcome.

This round has had a very different flavor from previous work group meetings. With the good budget news and the stimulus funds that are coming to SLAC, we are hiring rather than reducing staff at the laboratory. I am pleased to see that lab staff are less concerned with job security, and more concerned with the functioning of the lab and how we can improve. I do hear complaints about areas of the lab that are not functioning well but they are most often constructive complaints. We know that we are not currently operating like the efficient, modern, effective multi-program laboratory we want to become. In some areas we are moving forward decisively. In other areas we are really struggling. We talk frankly about this in the work group meetings. I am impressed by the positive and forward looking attitudes expressed.

The workgroup meetings also discuss SLAC science programs. The commissioning news from LCLS is outstanding (stay tuned on that subject!) Everyone at the lab should take pride in how well that program is going. I look forward to the remaining sessions. I appreciate the frank feedback and uninhibited discussions.

SSRL Beamline 14 Sees First Light

(Photo webcam image of first light at SSRL Beamline 14)
The first X-ray light from Beamline 14 (white spot) hits a florescence screen in this webcam image. (Image courtesy of Daniel Harrington.)

Last week, X-ray light for the first time streamed into the new Beamline 14-1 hutch at the Stanford Synchrotron Radiation Lightsource.

"When you open a beamline and see first light, there is a great feeling of relief and satisfaction," said Engineering Physicist Daniel Harrington, who served as project manager for construction of this beamline. "When the first users arrive later this year, they will conduct macromolecular crystallography experiments here, looking at what you might call the molecules of life."

Researchers use macromolecular crystallography to study the function of a large range of molecules, such as cellular proteins, DNA, and RNA macromolecules, that have biological and biomedical impact. When purified and crystallized forms of these macromolecules are placed in the beam, the crystals diffract the X-rays. This creates a pattern of X-rays that can be analyzed to determine the sample's three-dimensional structure at a level that identifies the location of each atom. This technique was used for the structural part of the work that awarded Professor Roger Kornberg the 2006 Nobel PrizeRead more...

Word of the Week: Accelerator

Accelerators at SLAC are surprisingly abundant, and come in all sizes. This structure in the Klystron Department was once used in tests. (Photo by Lauren Schenkman.)

A particle accelerator uses electric fields to propel subatomic particles to speeds rivaling that of light. At SLAC, the first accelerator that comes to mind is generally the klystron-powered 2-mile linac. But the linac's 240 klystrons could also be considered accelerators; inside them, electrons are accelerated from a heated piece of metal, or cathode, with a pulse of electricity. Consider too every bulky computer monitor or television, in which a uniform electric field speeds electrons from a cathode to the phosphor-coated screen. Accelerated electron beams are also used on site in a special welding machine and certain microscopes.

SLAC has other large accelerators, too. For example, at the Stanford Synchrotron Radiation Lightsource, electrons zip from a cathode, through a 30-foot-long linear accelerator and around the 460-foot circumference of the booster ring before they've been accelerated to the right energy for the SPEAR3 storage ring. SPEAR3 also kicks new energy into electrons as they orbit, as did the now-retired PEP-II storage ring.

As a center for accelerator research and development, SLAC is also home to many test accelerators. Parts for future colliders get a workout at the 100-foot-long Next Linear Collider Test Accelerator, while in the Accelerator Structure Test Area, scientists have powered dozens of accelerator structures ranging in size from several feet to just inches. And SLAC Gun Test Facility researchers work with just one or two cells—an accelerator that fits in your hand.

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