Femtosecond Width X-ray Generation with the SLAC Linac and the FFTB Beamline

We describe a new Sub-Picosecond Photon Source (SPPS) based on proposal to generate 30 GeV bunches as short as 30 fs rms with the SLAC linac. The bunch is compressed in three stages, starting with the existing ring-to-linac compressor. A second stage of compression will be added in the form of a simple magnetic chicane installed at the 9-GeV location in the linac. The short bunch then generates a strong wakefield in the linac which follows the chicane. This wake provides a large correlated energy spread which allows a third stage of compression in the bends of the existing Final Focus Test Beam (FFTB) beamline. A proposed 10 m long undulator in the FFTB can deliver {approx} 10{sup 8} 1.5 {angstrom} photons per pulse in a 0.1% bandwidth with a peak brightness of {approx}10{sup 25} photons/sec/mm{sup 2}/mrad{sup 2}/0.1% BW, in a pulse width of {approx}80 fs FWHM. The short electron bunches with peak currents as high as 30 kA are also ideal for plasma and wakefield studies as well as providing abundant R&D possibilities for verifying short bunch behavior in the future Linac Coherent Light Source (LCLS).