• F.-J. Decker, R. Akre, A. Brachmann, W.S. Colocho, Y.T. Ding, D. Dowell, P. Emma, J.C. Frisch, A. Gilevich, G.R. Hays, P. Hering, Z. Huang, R.H. Iverson, K.D. Kotturi, A. Krasnykh, H. Loos, A. Miahnahri, H.-D. Nuhn, D.F. Ratner, J.L. Turner, J.J. Welch, W.E. White, J. Wu
  SLAC, Menlo Park, California

Funding: Work supported by Department of Energy contract DE-AC03-76SF00515.

The beam stability for the Linac Coherent Light Source (LCLS) at SLAC is important for good X-Ray operation. Although most of the jitter tolerances are met, there is always room for improvement. Besides the short term pulse-to-pulse jitter, we will also discuss oscillation sources of longer time cycles from seconds (feedbacks), to minutes (cooling systems), and up to the 24 hours caused by the day-night temperature variations.

• F.-J. Decker, R. Akre, K.J. Bertsche, A. Brachmann, W.S. Colocho, Y.T. Ding, D. Dowell, P. Emma, J.C. Frisch, A. Gilevich, G.R. Hays, P. Hering, Z. Huang, R.H. Iverson, A. Krasnykh, H. Loos, H.-D. Nuhn, D.F. Ratner, H. Smith, J.L. Turner, J.J. Welch, W.E. White, J. Wu
  SLAC, Menlo Park, California

Funding: Work supported by Department of Energy contract DE-AC03-76SF00515.

The electron beam for the Linac Coherent Light Source (LCLS) at SLAC is accelerated by disk-loaded RF structures over a length of 1 km. The mainly longitudinal field can sometimes exhibit transverse components, which kick the beam in x and/or y. This is normally a stable situation, but when a klystron, which powers some of these structures, has to be switched off and another one switched on, different kicks can lead to quite a different orbit. Some klystrons, configured in an energy and bunch length feedback, caused orbit changes of up to 1 mm, which is about 20 times the σ beam size. The origins and measurements of these kicks and some efforts (orbit bumps) to reduce them will be discussed.