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The Center for Bright Beams, A National Science Foundation Science and Technology Center

Online storage ring optimization using dimension-reduction and genetic algorithms

W. F. Bergan, I. V. Bazarov, C. J. R. Duncan, D. B. Liarte, D. L. Rubin, and J. P. Sethna

Histogram showing beam size measurements from CESR. More in caption.

A historgam with vertical beam size on the x-axis. Two peaks show one with uncorrected beam size and one with beam size after 8-Knob RCDS tuning. The histogram for the beam after tuning is taller.

Histogram of hundreds of experimental vertical beam size measurements both using the standard conditions for light-source operations with no additional tuning and after tuning with a local optimizer using the best 8 eigenparameters. A clear improvement is observed.

Particle accelerators are complex machines with a large number tunable parameters, complicating searches for optimal machine conditions. However, we have found that these "bare" parameters can often be grouped into new "eigenparameters," such that the tuning ability of all the original parameters is concentrated in only a few eigenparameters. At the Cornell Electron Storage Ring (CESR), we have reduced the 81 magnet strengths useful for minimizing the vertical beam size into 8 eigenparameters, and experimentally demonstrated their ability to reduce the beam size when used by various optimization algorithms. This dimension-reduction permits faster tuning of accelerators.

Relation to CBB goals:


Our results advance the CBB goal of delivering better control of beams in particle storage rings.

Potential applications:


X-ray light-sources, such as CESR, stand to benefit by using the techniques we developed to reduce time spent tuning their machines, making more time to do X-ray science.