THE NEW LCLS-II PROJECT : STATUS AND CHALLENGES *

The LCLS-II was an upgrade of the LCLS which essentially replicated the LCLS in another tunnel using the middle 1/3 of the SLAC S-band linac. In August 2013, the project was doubled in scope and redirected towards providing MHz-rate x-ray pulses from 0.2 to 5.0 keV while still supporting the ongoing program at the LCLS. The new accelerator is now based on a 4.0 GeV SCRF linac installed in the front of the SLAC linac tunnel. Key features of the LCLS-II linear accelerator are described, so that LCLS-II can be responsive to the July 2013 recommendation of DOE BESAC for a fully coherent, CW FEL with photon energies up to ~5 keV.