X-ray optics design studies for the 1.5 to 15-A Linac Coherent Light Source (LCLS) at Stanford Linear Accelerator Laboratory

In recent years, comprehensive design studies have been initiated on angstrom-wavelength free-electron laser (FEL) schemes based on driving highly compressed electron bunches from a multi-GeV linac through long undulators. The output parameters of these sources, when operated in the so-called self-amplified spontaneous emission mode, include lasing powers in the 10-100 GW range, full transverse and low-to- moderate longitudinal coherence, pulse durations in the 50- 500 fs range, broad spontaneous spectra with total power comparable to the coherent output, and flexible polarization parameters. In this paper we summarize the status of design studies of the x-ray optics system and components to be utilized in the SLAC linac coherent light source, a 1.5-15 angstrom FEL driven by the last kilometer of the SLAC three kilometer S-band linac. Various aspects of the overall optical system, selected instrumentation and individual components, radiation modeling, and issues related to the interaction of intense sub-picosecond x-ray pulses with matter, are discussed.