RESEARCH-AND-DEVELOPMENT TOWARD A 4.5-1.5-ANGSTROM LINAC COHERENT-LIGHT SOURCE (LCLS) AT SLAC

In recent years significant studies have been initiated on the feasibi lity of utilizing a portion of the 3 km S-band accelerator at SLAC to drive a short wavelength (4.5-1.5 Angstrom) Linac Coherent Light Sourc e (LCLS), a Free-Electron Laser (FEL) operating in the Self-Amplified Spontaneous Emission (SASE) regime. Electron beam requirements for sin gle-pass saturation in a minimal time include: 1) a peak current in th e 7 kA range, 2) a relative energy spread of <0.05%, add 3) a transver se emittance, epsilon [rad-m], approximating the diffraction-limit con dition epsilon=lambda/4 pi, where lambda[m] is the output wavelength. Requirements on the insertion device include field error levels of 0.0 2% for keeping the electron bunch centered on and in phase with the am plified photons, and a focusing beta of 8 m/rad for inhibiting the dil ution of its transverse density. Although much progress has been made in developing individual components and beam-processing techniques nec essary for LCLS operation down to similar to 20 Angstrom, a substantia l amount of research and development is still required in a number of theoretical and experimental areas leading to the construction and ope ration of a 4.5-1.5 Angstrom LCLS. In this paper we report on a resear ch and development program underway and in planning at SLAC for addres sing critical questions in these areas. These include the construction and operation of a linac test stand for developing laser-driven photo cathode rf guns with normalized emittances approaching 1 mm-mrad; deve lopment of advanced beam compression, stability, and emittance control techniques at multi-GeV energies; the construction and operation of a FEL Amplifier Test Experiment (FATE) for theoretical and experimental studies of SASE at IR wavelengths; an undulator development program t o investigate superconducting, hybrid/permanent magnet (hybrid/PM), an d pulsed-Cu technologies; theoretical and computational studies of hig h-gain FEL physics and LCLS component designs; development of X-ray op tics and instrumentation for extracting, modulating, and delivering ph otons to experimental users; and the study and development of scientif ic experiments made possible by the source properties of the LCLS.