Possibility of downsizing X-ray free electron laser

Laser sources in the hard X-ray region have already become a reality at some free electron laser (FEL) facilities. However, typical hard X-ray FELs use an accelerator that is several km long to generate a ~10 GeV electron beam with ~kA peak current to drive the FEL. Dr. D. Xiang (SLAC National Accelerator Laboratory, USA) is proposing an alternative technique to generate an electron beam. He discusses the possibility of downsizing an X-ray FEL by this method. In his calculation, a 1.5 Å X-ray FEL with a saturation length within 30 m using a 3.8 GeV electron beam could be feasible. For more information, see the paper, "Laser assisted emittance exchange: Downsizing the x-ray free electron laser", D. Xiang, Phys. Rev. ST Accel. Beams 13, 010701 (2010).