• C. Steier, B.J. Bailey, K.M. Baptiste, W. Barry, A. Biocca, W.E. Byrne, P.W. Casey, M.J. Chin, R.J. Donahue, R.M. Duarte, M.P. Fahmie, J. Gath, S.R. Jacobson, J. Julian, J.-Y. Jung, A.M. Kritscher, S. Kwiatkowski, S. Marks, J.P. McKean, R.S. Müller, H. Nishimura, J.W. ONeill, G.J. Portmann, S. Prestemon, D. Robin, S.L. Rossi, F. Sannibale, T. Scarvie, D. Schlueter, B. Shuman, A.Z. Smith-Baumann, G.D. Stover, CA. Timossi, W. Wan, T. Warwick, J.M. Weber, R.P. Wells, E.C. Williams
  LBNL, Berkeley, California

Funding: This work was supported by the Director, Office of Science, U. S. Department of Energy under Contract No. DE-AC02-05CH11231.

The upgrade of the Advanced Light Source to enable top-off operation has been ongoing for the last four years. Activities over the last year have centered around radiation safety aspects, culminating in a systematic proof that top-off operation is equally safe as decaying beam operation, followed by commissioning and full user operations. Top-off operation at the ALS provides a very large increase in time-averaged brightness to ALS users (by about a factor of 10) as well as improvements in beam stability. The presentation will provide an overview of the radiation safety rationale, commissioning results, as well as experience in user operations.

• K.M. Baptiste, M.O. Balagot, W. Barry, P.W. Casey, H.K. Chen, R.S. Müller, D. Robin, C. Steier, J.M. Weber
  LBNL, Berkeley, California

Funding: Supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

ALS has been upgraded by adding Top-Off Mode, a new mode of operation to the existing modes of Fill and Stored Beam. The Top-Off Mode permits injection of 1.9GeV electron beam into the Storage Ring, with the safety shutters open, once certain strict conditions are met and maintained. Top-Off Mode enables User operation without an interruption caused by mode switching between the Stored Beam Mode when safety shutters are open, to the Fill Mode with the safety shutters closed and back. The conditions necessary to permit Top-Off Mode are; stored beam is present, the energies are matched between the injector and storage ring, a select set of storage ring lattice magnets are operating at the correct current levels, and radiation losses are minimized. If certain combinations of these conditions are not met, a potentially dangerous condition of injecting electrons down a users beam line can exist. Therefore a system of mode control, energy match, lattice match and stored beam interlocks are needed to control the injected beam prohibiting potentially dangerous conditions. In this paper we will present the Top-Off Mode Beam Interlock system requirements, design, and operational parameters.

Slides