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Schlueter, R.D.

Paper Title Page
MPPT067 Stray Field Reduction in ALS Eddy Current Septum Magnets 3718
 
  • D. Shuman, W. Barry, S. Prestemon, R.D. Schlueter, C. Steier, G.D. Stover
    LBNL, Berkeley, California
 
  Funding: This work was supported by the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.

Stray field from an eddy current septum magnet adversely affects the circulating beam and can be reduced using several techniques. The stray field time history typically has a fast rise section followed by a long exponential decay section when pulsed with a half sine drive current. Changing the drive current pulse to a full sine has the effect of both reducing peak stray field magnitude by ~3x, and producing a quick decay from this peak to a lower field level which then has a similar long decay time constant as that from the half sine only drive current pulse. A method for tuning the second half sine (reverse) drive current pulse to eliminate the long exponential decay section is given.

 
RPAE067 Investigations, Experiments, and Implications for Using Existing Pulse Magnets for 'topoff' Operation at the Advanced Light Source 3727
 
  • G.D. Stover, K.M. Baptiste, W. Barry, J. Gath, J. Julian, S. Kwiatkowski, S. Prestemon, R.D. Schlueter, D. Shuman, C. Steier
    LBNL, Berkeley, California
 
  Funding: This work was supported by the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.

ALS top-off mode of operation will require injection of the electron beam from the Booster Ring into the Storage Ring at the full ALS energy level of 1.9GeV. Currently the Booster delivers a beam at 1.5GeV to the Storage Ring where it is then ramped to the full energy and stored for the user operation. The higher Booster beam energy will require the pulse magnets in the Booster and Storage Rings to operate at proportionally higher magnetic gap fields. Our group studied and tested the possible design and installation modifications required to operate the magnets and drivers at "top-off" levels. Our results and experiments show that with minor electrical modifications all the existing pulse magnet systems can be used at the higher energy levels, and the increased operational stresses should have a negligible impact on magnet reliability. Furthermore, simple electrical modifications to the storage ring thick septum will greatly reduce the present level of septum stray leakage fields into the storage ring beam.