Undulator Hall

Undulator Hall

There are 32 undulators with 3,000 pairs of magnets in the Undulator Hall, spread out over 100 meters.

High-energy electrons zip through the linear accelerator at almost the speed of light and enter the football-field sized Undulator Hall. An undulator is a device that wiggles electrons back and forth between two rows of magnets, which have their poles arranged in an alternating positive-negative/negative-positive pattern. The negatively charged electrons are attracted to the positive poles. As they zigzag back and forth between the sets of magnets, they emit some of their energy in the form of X-rays. The emitted X-rays accumulate and reinforce each other with time and distance, creating a very bright, powerful and coherent beam we can use for research.

What happens to the electrons when they’re done generating X-rays? A powerful magnet directs them down into the “beam dump,” where they’re absorbed by a piece of metal in the ground. Meanwhile, the coherent X-rays are unaffected by the magnet and keep moving forward to the experimental halls.

X-ray Laser Animated Fly-through

Take a tour with an electron's-eye-view through SLAC's revolutionary new X-ray laser facility with this 5 1/2 minute animation. See how the X-ray pulses are generated using the world's longest linear accelerator along with unique arrays of machinery specially designed for this one-of-a-kind tool.

For more than 40 years, SLAC's two-mile-long linear accelerator (or linac) linac has produced high-energy electrons for cutting-edge physics experiments. Since 2009, SLAC's linac has entered a new phase of its career with the creation of the Linac Coherent Light Source (LCLS).

LCLS produces pulses of X-rays more than a billion times brighter than the most powerful existing sources, the so-called synchrotron sources which are also based on large electron accelerators.

The ultrafast X-ray pulses are used much like flashes from a high-speed strobe light, enabling scientists to take stop-motion pictures of atoms and molecules in motion, shedding light on the fundamental processes of chemistry, technology, and life itself.


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