WiFEL Layout
The diagram shows the proposed layout of the Wisconsin Free Electron Laser accelerator, undulators, and beamlines. Click on the image for a larger version.
More information about the WiFEL can be found in the project description of the WiFEL R&D proposal (PDF File) .
How Does a Free Electron Laser Work?
When electrons change their direction of motion they produce light. If they are
moving near the speed of light (relativistic), they can generate light of very high frequency; for example, ultraviolet and x-rays.
In a free electron laser, an electron beam is sent through a long array of magnets (an undulator) that causes the beam to jiggle and emit light. If the electrons are close enough they will actually jiggle in unison in response to the light they produce and make a laser beam of radiation. This is how a free electron laser (or FEL) works.
The radiation can be "seeded" by conventional lasers and up converted to higher frequencies. In this way, the FEL can produce pulses measured in quadrillionths of a second, called a femtoseconds. These super short pulses can be used to study chemical and physical reactions as they happen.
Since the electrons jiggle in unison, the light is called "coherent" and can be used for imaging--making holograms of molecules, for example.