Wednesday, April 22, 2009

LCLS X-Ray Laser Powers Up

Looks like we have a few major facilities here going online at almost the same time. First we had the National Ignition Facility completing its construction and commissioning. Now it appears that the LCLS at SLAC have sent its first beam through, producing the world's first hard x-ray laser.

The LCLS works differently than most lasers. In a standard laser, a light-emitting material, such as a certain type of crystal, sits between two mirrors, and the light bouncing back and forth stimulates the atoms in the material to crank out lots more light in the form of a laser beam. There are no mirrors for x-rays, however. So instead, the LCLS relies on part of SLAC's 3-kilometer-long linear accelerator to fire a beam of electrons at light speed through specialized magnets called undulators. The magnets make the beam wiggle and produce some x-rays. The x-rays then travel along with the electrons and separate them into bunches, and the bunches produce x-rays far more efficiently. Thanks to that feedback, an x-ray laser beam emerges--as it did last week, SLAC officials report today.

The next few months will be quite fascinating. With the NIF operating at full blast {pun intended}, the beam test at LCLS being ramped up, the Tevatron in a rush to get as much data as possible, and the good ole LHC being powered up some time in October, it is a fun time for physics!


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