• R.A. Bosch
  UW-Madison/SRC, Madison, Wisconsin
• R.J. Bosch
  Harvard School of Public Health, Boston

We derive the average and rms bunching for Poisson statistics. For a bunch with a large number of particles, the results are practically equivalent to a bunch with a fixed number of independent particles.

• R.A. Bosch, K.J. Kleman
  UW-Madison/SRC, Madison, Wisconsin
• J. Wu
  SLAC, Menlo Park, California

In high-current magnetic bunch compression, shot-noise-induced energy and current fluctuations at the chicane entrance may cause microbunching. For the case where the energy fluctuations are the primary cause of microbunching, we perform approximate simulations with fewer particles than the bunch population by using a reduced value of the space-charge impedance upstream of the chicane. This method is applied to bunch-compressor designs for the Wisconsin Free Electron Laser (WiFEL).

• 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.