• M. Böge, A. Lüdeke, A. Streun
  PSI, Villigen
• Å. Andersson
  MAX-lab, Lund

Utilizing a large number of non-dispersive (24) and dispersive (6) skew quadrupoles the betatron coupling and the vertical spurious dispersion can be simultaneously reduced to extremely small values. As a result the achieved vertical emittance begins to approach its ultimate limit, set by the fundamental quantum nature of synchrotron radiation, which in the SLS case is ~0.55 pm.rad. At the same time emittance measurements based on the fitting of a diffraction limited vertical photon beam from a dipole have been pushed to the limit in order to verify this ultra-low vertical emittance.

• A. Streun, M. Böge, J.T.M. Chrin, A. Lüdeke
  PSI, Villigen

Recently the energy acceptance and Touschek lifetime of the storage ring of the Swiss Light Source (SLS) could be successfully set to values in agreement with simulations for an ideal lattice. This was finally achieved through control of linear coupling and symmetrization of the sextupole pattern. 36 small corrector magnets were installed for this purpose as additional windings on the ring sextupoles: 30 skew quadrupoles (24 at zero and 6 at maximum dispersion) and 6 auxiliary sextupoles. Base for the success of these measures were previous corrections of dipolar and quadrupolar errors, which we will summarize briefly.

• A. Streun, M. Böge, N. Milas, F. Müller, V. Schlott, H. Sigg
  PSI, Villigen
• G.A. Amatuni, D. Gishyan, K. Manukyan, A. Sargsyan
  CANDLE, Yerevan

Recently tentative top-up operation of the Swiss Light Source (SLS) storage ring at low momentum compaction factor has been started. We will present an analysis of the longitudinal dynamics and simulations of the injection process, and explain our method to ensure closed orbit stability. First experimental results will be shown and compared to the model predictions.

• K. Manukyan
  YSU, Yerevan
• G.A. Amatuni, A. Sargsyan, V.M. Tsakanov
  CANDLE, Yerevan
• M. Böge, A. Streun
  PSI, Villigen

An online measurement of the beam energy spread is based on the analysis of the decoherence/recoherence signals obtained from the beam position monitors after a single turn beam excitation by a pinger magnet. Furthermore the analysis allows calibration of the model in terms of higher order chromaticities and amplitude dependant tune shifts. An analytical model including 1st and 2nd order chromaticities and amplitude dependant tune shift will be presented.

• M. Ivanyan, V.M. Tsakanov, A. Vardanyan
  CANDLE, Yerevan
• M.M. Dehler, T. Schmidt, A. Streun
  PSI, Villigen

The longitudinal and transverse impedances of CPMU (cryogenic permanent magnet undulators) of the SLS storage ring are evaluated. The study takes into account the walls frequency dependent conductivity and the electrical and magnetic properties of the material at low temperature.