Improving the nonlinear performance of the HEPS baseline design with genetic algorithm

TL;DR

This paper uses genetic algorithms to optimize the linear optics of the HEPS baseline design, significantly improving its nonlinear performance while maintaining low emittance, by tuning magnetic fields and working points.

Contribution

It introduces a genetic optimization approach to enhance nonlinear dynamics in HEPS design without increasing emittance, exploring solution space for better performance.

Findings

Feasible to improve nonlinear performance with genetic optimization.

Weaker sextupoles can be used while maintaining emittance.

Optimal tuning of magnetic fields and working points enhances nonlinear stability.

Abstract

The baseline design for the High Energy Photon Source has been proposed, with an emittance of 60 pm.rad within a circumference of 1.3 kilometers. Nevertheless, the nonlinear performance of the design needs further improvements to enlarge both the dynamic aperture and the momentum acceptance. In this study, genetic optimization of the linear optics is performed, so as to find all the possible solutions with weaker sextupoles and hence weaker nonlinearities, while keeping the emittance at the same level as the baseline design. These obtained solutions enable us to explore the dependence of nonlinear dynamics on the working point. The result indicates that with the same layout, it is feasible to obtain much better nonlinear performance with a delicate tuning of the magnetic field strengths and a wise choice of the working point.