From the Director of LCLS Construction:
My Thanks to the LCLS Collaboration and SLAC
In my life before SLAC, I had the privilege to participate (in various capacities) in the design, construction and commissioning of two linacs, two synchrotrons, four storage rings and three FELs (free-electron lasers). Now I have had the privilege to be in SLAC's Main Control Center on April 10, when the Linac Coherent Light Source became a 1.5 angstrom laser. I don't expect I will ever, as long as I live, see such a beautiful, smooth turn-on of any light source. With each undulator placed on the beam path, the FEL power increased by a factor of about 2.3; two hours into the first attempt at lasing, the pinpoint of FEL light from twelve undulators was nearly 2,000-fold more intense than plain old undulator radiation. The team called it quits at 11:30 p.m. that night. When they returned at 8:00 a.m. the next morning, the FEL light came back as soon as the shutter was opened.
The FEL power is much higher now, only two weeks later.
Engineers in SLAC Metrology measure and calibrate an
LCLS undulator magnet.
I am in awe of the near-perfection to which LCLSers from every corner of every department of SLAC worked in partnership with LCLS collaborators at UCLA and Argonne National Laboratory to make the first operation of the FEL look as simple as turning on a light switch. To make the LCLS lase required a photocathode gun and laser that didn't quite exist yet, producing an electron beam of near-impossibly small size and high current, shot through a 5-millimeter-diameter pipe threading through a 130-meter-long undulator. The electron beam must literally travel as straight as a light beam, with only a few—5 or so—micrometers' room for error. To put that into perspective, a sheet of notebook paper is 50 micrometers thick. And it all worked just right, from the first attempt.
Registration Open for SuperB Project Workshop and Proto-Collaboration Meeting IV
SLAC will host the fourth in a series of workshops on October 5–9, 2009 to continue efforts towards the design and research and development needs for the SuperB project to be built near Frascati, Italy. This series is intended to help build an international collaboration in support of the project, and produce an optimized design for the high luminosity SuperB flavor factory machine and detector.
The meeting agenda will comprise both plenary and parallel working sessions. Progress on outstanding design issues and the R&D needed to reach decisions will be emphasized. All facets of the project will be addressed including
physics, accelerator, detector, computing, conventional facilities and organization
of the project.
For registration and further information, see the
meeting Web site.
Based on the last third of SLAC's two-mile linac, the LCLS is the world's first hard X-ray laser.
(Artist's rendering of the LCLS at SLAC.)
Word of the Week: Laser
Laser is an acronym for "light amplification by stimulated emission of radiation."
In a conventional laser, light bounces back and forth through a special amplifying medium, causing atoms to emit more and more photons with each trip. Eventually, some photons escape through a partially transparent mirror, each wave traveling in phase with the next to form an intense, narrow beam of single-wavelength light.
When lasers were first invented, in 1960, they were described as
looking for a problem. But in a very short time they became ubiquitous in society. We use lasers to scan barcodes at the grocery store, play DVDs, slice through metal and make high-precision cuts during surgery.
Laser light can shine in the visible spectrum, or any other wavelength. To make laser light in the high-energy X-ray range, the new Linac
Coherent Light Source streams the SLAC linear accelerator's electron beam
through a series of alternating magnets. With the resulting side-to-side
wiggles, the electrons emit
ultrashort laser X-ray pulses of unprecedented brightness, making it possible for researchers to capture images on the atomic scale and illuminate the fundamental behavior of molecules.