• R.A. Bosch, J. Bisognano, M. Bissen, M.A. Green, H. Höchst, K. Jacobs, K.J. Kleman, R.A. Legg, R. Reininger, R. Wehlitz
  UW-Madison/SRC, Madison, Wisconsin
• W. Graves, F.X. Kärtner, D.E. Moncton
  MIT, Cambridge, Massachusetts

The University of Wisconsin-Madison/Synchrotron Radiation Center and MIT are developing a design for a seeded VUV/soft X-ray Free Electron Laser serving multiple simultaneous users. The present design uses an L-band CW superconducting 2.2 GeV electron linac to deliver 200 pC bunches to multiple FELs operating at repetition rates from kHz to MHz. The FEL output will be fully coherent both longitudinally and transversely, with tunable pulse energy, cover the 5-900 eV photon range, and have variable polarization. Bunch seeding at higher photon energies will be done with HHG laser pulses to avoid the need for fresh electron bunches. This unique facility is expected to enable new science through ultrahigh resolution in the time and frequency domains, as well as coherent imaging and nano-fabrication. We have proposed a program of R&D to address the most critical aspects of the project, including prototyping of a CW superconducting RF photoinjector, and development of conventional laser systems for MHz seeding of the FEL. We present an overview of the facility and our proposed R&D plan.