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In this issue:
Gun Play at SPEAR3
Science Today: BaBar SVT: Eight Years of Great Physics
SLAC Communications Office Trailer-Warming Party

SLAC Today

Thursday - July 12, 2007

John Schmerge in the SPEAR3 injector vault with the laser setup and cathode gun used to test a new method of generating electrons. (Click on image for larger version.)

Gun Play at SPEAR3

Last month a small team of SLAC physicists conquered another challenge in the quest to take the SPEAR3 synchrotron permanently up to its full operational capability of 500 milliamperes (mA). Using the existing electron gun and accelerator, the team demonstrated that a laser can be used to create a large pulse of electrons, which will aid rapid injection of beam into the ring.

As it now operates, SPEAR3's electron gun produces electron pulses as the gun's cathode is heated to nearly 2,000 degrees Fahrenheit (1,050 Celsius). This configuration allows only minimal control over the timing and the amount of power in each pulse because the hot cathode continually emits a pulsed stream of a few thousand electron bunches, of which only five or six are useable for injection into the SPEAR3 storage ring. Using a brief laser pulse to stimulate a burst of electrons eliminates limitations associated with a hot cathode, producing a single, precise electron microbunch with much higher charge.

"This is a first step," said physicist John Schmerge who worked on the project. "Basically what we've done is turn off the heater and put in a laser."  Read more...

(Daily Column - Science Today)

BaBar SVT: Eight Years of Great Physics

(Photo - SVT)
The Silicon Vertex Tracker.
(Image courtesy of Peter Ginter.)

Right at the center of BaBar, inside its protection shield, lives the Silicon Vertex Tracker (SVT), a complex device that uses silicon crystals coated with superfine metal strips (about 300,000 of them) to accurately measure the position of the charged particles crossing it. Following these footprints, it is possible to find the point of origin of the particles—the Vertex—pretty much in the same way that by following the tracks left by a rabbit running on fresh snow it is possible to find its burrow.


Communications Office Trailer-Warming Party

(Photo - Com trailers)
Click on image for larger version.

The entire lab is invited to celebrate the communications office's new location this afternoon from 3:00 to 5:00 p.m. in the parking lot outside Trailers 266 and 267.

Enjoy the full glory of our new digs—and the new flamingos. Food, drink, karaoke, a tattoo bar, pin-the-bling-on-Einstein, and of course a tour of the trailers will be waiting for you.

Come for the food, the company, or just to see our new space! We hope to see you there.

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