A multi-objective genetic algorithm is developed for optimizing
nonlinearities in diffraction limited storage rings. This algorithm determines
sextupole and octupole strengths for chromaticity correction that deliver
optimized dynamic aperture and beam lifetime. The algorithm makes use of
dominance constraints to breed desirable properties into the early generations.
The momentum aperture is optimized indirectly by constraining the chromatic
tune footprint and optimizing the off-energy dynamic aperture. The result is an
effective and computationally efficient technique for correcting chromaticity
in a storage ring while maintaining optimal dynamic aperture and beam lifetime.
This framework was developed for the Swiss Light Source (SLS) upgrade project.Comment: 12 pages, 14 figure
