• S.P. Weathersby, A. Novokhatski
  SLAC, Menlo Park, California

The geometry of storage ring collider interaction regions present an impedance to beam fields resulting in the generation of additional electromagnetic fields (higher order modes or wake fields) which affect the beam energy and trajectory. These affects are computed for the Super B interaction region by evaluating longitudinal loss factors and averaged transverse kicks for short range wake fields. Results indicate at least a factor of 2 lower wake field power generation in comparison with the interaction region geometry of the PEP-II B-factory collider. Wake field reduction is a consideration in the Super B design. Transverse kicks are consistent with an attractive potential from the crotch nearest the beam trajectory. The longitudinal loss factor scales as the -2.5 power of the bunch length. A factor of 60 loss factor reduction is possible with crotch geometry based on an intersecting tubes model.

• M.P. Dunning, E.R. Colby, Y.T. Ding, J.T. Frederico, A. Gilevich, C. Hast, R.K. Jobe, D.J. McCormick, J. Nelson, T.O. Raubenheimer, K. Soong, G.V. Stupakov, Z.M. Szalata, D.R. Walz, S.P. Weathersby, M. Woodley, D. Xiang
  SLAC, Menlo Park, California
• J.N. Corlett, G. Penn, S. Prestemon, J. Qiang, D. Schlueter, M. Venturini, W. Wan
  LBNL, Berkeley, California
• P.L. Pernet
  EPFL, Lausanne

In this paper we describe the technical design of an on-going proof-of-principle echo-enabled harmonic generation (EEHG) FEL experiment in the Next Linear Collider Test Accelerator (NLCTA) at SLAC. The experiment was designed through late 2009 and built and installed between October 2009 and January 2010. We present the design considerations, the technical realization and the expected performances of the EEHG experiment.

• D. Xiang, E.R. Colby, Y.T. Ding, M.P. Dunning, J.T. Frederico, A. Gilevich, C. Hast, R.K. Jobe, D.J. McCormick, J. Nelson, T.O. Raubenheimer, K. Soong, G.V. Stupakov, Z.M. Szalata, D.R. Walz, S.P. Weathersby, M. Woodley
  SLAC, Menlo Park, California
• J.N. Corlett, G. Penn, S. Prestemon, J. Qiang, D. Schlueter, M. Venturini, W. Wan
  LBNL, Berkeley, California
• P.L. Pernet
  EPFL, Lausanne

ECHO-7 is a proof-of-principle echo-enabled harmonic generation* FEL experiment in the Next Linear Collider Test Accelerator (NLCTA) at SLAC. The experiment aims to generate coherent radiation at 318 nm and 227 nm, which is the 5th and 7th harmonic of the infrared seed laser. In this paper we present the preliminary results from the commissioning run of the completed experimental setup which started in April 2010.

* G. Stupakov, PRL, 102, 074801 (2009); D. Xiang and G. Stupakov, PRST-AB, 12, 030702 (2009).