• 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.

• U. Wienands, B. Allen, W.S. Colocho, R.A. Erickson, M. Stanek
  SLAC, Menlo Park, California

Funding: Work supported by US DOE

For LCLS, an uptime of 95% of the scheduled beam time is aimed for. This is a challenging goal for a linac-driven facility, exceeding typical up time during PEP-II running by a significant amount. During the 2008 and the 2009 LCLS beam-commissioninng runs we have been gathering and analysing statistics to identify the worst offenders as far as downtime is concerned. In 2008, an overall hardware uptime of 90% was achieved, indicating the need to decrease our downtime by a factor of two. One approach to focus the effort has been to identify those faults that cause the worst performance for a system in a given time period and focus on these. Another one is to compare our MTTR performance with that of other facilities thus identifying where our processes might be improved. In this paper we will show how we track our performance and examples of the benefit of addressing identified reliability issues.