• M.E. Biagini, D. Alesini, R. Boni, M. Boscolo, T. Demma, A. Drago, M. Esposito, S. Guiducci, F. Marcellini, G. Mazzitelli, M.A. Preger, P. Raimondi, C. Sanelli, M. Serio, A. Stecchi, A. Stella, S. Tomassini, M. Zobov
  INFN/LNF, Frascati (Roma)
• M.A. Baylac, J.-M. De Conto, Y. Gomez-Martinez, N. Monseu, D. Tourres
  LPSC, Grenoble
• K.J. Bertsche, A. Brachmann, Y. Cai, A. Chao, M.H. Donald, A.S. Fisher, D. Kharakh, A. Krasnykh, N. Li, D.B. MacFarlane, Y. Nosochkov, A. Novokhatski, M.T.F. Pivi, J. Seeman, M.K. Sullivan, A.W. Weidemann, J. Weisend, U. Wienands, W. Wittmer, A.C. de Lira
  SLAC, Menlo Park, California
• S. Bettoni
  CERN, Geneva
• B. Bolzon, L. Brunetti, A. Jeremie
  IN2P3-LAPP, Annecy-le-Vieux
• J. Bonis, G. Le Meur, B.M. Mercier, F. Poirier, C. Prevost, C. Rimbault, F. Touze, A. Variola
  LAL, Orsay
• F. Bosi
  INFN-Pisa, Pisa
• A. Chancé, F. Méot, O. Napoly
  CEA, Gif-sur-Yvette
• R. Chehab
  IN2P3 IPNL, Villeurbanne
• I. Koop, E.B. Levichev, S.A. Nikitin, P.A. Piminov, D.N. Shatilov, S.V. Sinyatkin
  BINP SB RAS, Novosibirsk
• S.M. Liuzzo, E. Paoloni
  University of Pisa and INFN, Pisa

The SuperB project is an international effort aiming at building in Italy a very high luminosity e⁺e^- (10³⁶ cm^-2 sec^-1) asymmetric collider at the B mesons cm energy. The accelerator design has been extensively studied and changed during the past year. The present design, - based on the new collision scheme, with large Piwinski angle and the use of 'crab' sextupoles, which has been successfully tested at the DAPHNE Phi-Factory at LNF Frascati, - provides larger flexibility, better dynamic aperture and in the Low Energy Ring spin manipulation sections, needed for having longitudinal polarization of the electron beam at the Interaction Point. The Interaction Region has been further optimized in terms of apertures and reduced backgrounds in the detector. The injector complex design has been also updated. A summary of the design status, including details on lattice and spin manipulation will be presented in this paper.

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

The Linac Coherent Light Source (LCLS) at SLAC is an x-ray Free Electron Laser with wavelengths of 0.15 nm to 1.5 nm. The electron beam stability is important for good lasing. While the transverse jitter of the beam is about 10-20% of the rms beam sizes, the jitter in the longitudinal phase space is a multiple of the energy spread and bunch length. At the lower energy of 4.3 GeV (corresponding to the longest wavelength of 1.5 nm) the relative energy jitter can be 0.125%, while the rms energy spread is with 0.025% five times smaller. An even bigger ratio exists for the arrival time jitter of 50 fs and the bunch duration of about 5 fs (rms) in the low charge (20 pC) operating mode. Although the impact to the experiments is reduced by providing pulse-by-pulse data of the measured energy and arrival time, it would be nice to understand and mitigate the root causes of this jitter. The thyratron of the high power supply of the RF klystrons is one of the main contributors. Another suspect is the multi-pacting in the RF loads. Phase measurements down to 0.01 degree (equals 10 fs) along the RF pulse were achieved, giving hints to the impact of the different sources.