• G.J. Portmann, K.M. Baptiste, W. Barry, M.P. Hertlein, J. Julian, S. Kwiatkowski, R. Low, D.W. Plate, D. Robin
  LBNL, Berkeley, California

Typically storage ring light sources operate with the maximum number of bunches possible with a gap for ion clearing. The Advanced Light Source (ALS) has 2 nanoseconds between the bunches and typically operates with 276 bunches out of a possible 328. For experimenters doing timing experiment this bunch separation is too small and would prefer to see only one or two bunches in the ring. In order to provide more flexible operations and substantially increase the amount of operating time for time-of-flight experimenters, it is being proposed to kick one bunch on a different vertical closed orbit. By spatially separating the light from this bunch from the main bunch train in the beamline, one could potentially have single bunch operation all year round. By putting this bunch in the middle of the ion clearing gap the required bandwidth of the kicker magnets is reduced. Using one kicker magnet running at the ring repetition rate (1.5 MHz), this bunch could be permanently put on a different closed orbit. Using multiple kicker magnets, this bunch could be locally offset at an arbitrary frequency. This paper will show some first results using such a system.

This work was supported by U.S. Department of Energy under Contract No. DE-AC03-76SF00098

• M.J. Chin, W. Barry, F. Sannibale, J.M. Weber
  LBNL, Berkeley, California

At the Advanced Light Source (ALS), imperfections in the injection system plus electron diffusion result in storage ring RF bucket contamination. A Virtex-4 FPGA is used to generate a Direct-Digital Synthesized (DDS) sinewave waveform at the vertical betatron tune frequency, which is synchronously gated on or off at the 1.6MHz ring orbit frequency. Any pattern on/off/invert in 328 buckets by 2ns at the ring orbit frequency can be set. An embedded Power-PC core in the FPGA provides TCP access for control and monitoring via a remote PC running LabVIEW.