• L.O. Dallin, M.S. de Jong
  CLS, Saskatoon, Saskatchewan

Coherent Synchrotron Radiation (CSR) is produced when short bunch lengths are set up in the Canadian Light Source storage ring. To achieve short bunches large negative dispersion is introduced into the straight regions of the lattice such that the momentum compaction can be made to approach zero. In this way CSR has been observed using a few single bunches with currents up to 10 mA per bunch at the nominal operating energy of 2.9 GeV. Attempts produce CSR with low bunch currents in many bunches were unsuccessful at 2.9 GeV. At 1.5 GeV, however, it is possible to achieve CSR with a total of 5 mA stored in over 70 bunches. CSR production is enhanced by operating at a horizontal tune where the chromaticity can be kept near zero. Tracking simulations in longitudinal phase space indicate enhanced stability at tunes lower than the nominal tune. The optimum tune does not depend on the fractional tune but rather there is a tune "window" at the center of which stable longitudinal motion can be maximized.

• T. Summers, D. Chabot, L.O. Dallin, M.J. Sigrist
  CLS, Saskatoon, Saskatchewan

Upgrades to the orbit control system at the Canadian Light Source (CLS) have resulted in increased beam stability and reproducibility. These upgrades include improving position information from the beam position monitors (BPMs) by modifying the data acquisition algorithm and switching to a real-time operating system. Beam motion has been reduced to an RMS deviation of less than 1 micron in both planes. Limiting the maximum corrector step has allowed the use of all singular values when inverting the BPM response matrix, resulting in much better orbit reproducibility. As well, improved lookup tables have been developed to compensate for the effects of changing undulator gaps and polarizations. Presently, work is underway to develop fast orbit correction with rates up to 100 Hz. Fast orbit correction will further reduce the residual perturbations caused by undulator activity and will allow fast ramping of superconducting wigglers.