IPAC2017 - List of Authors (Chao, H.C.)

Paper	Title	Page
MOPIK059	Linear and Nonlinear Optimizations of Combined 7BA-6BA Lattices for the Future Upgrade of SOLEIL	659
	A. Loulergue, P. Brunelle, H.C. Chao, A. Nadji, L.S. Nadolski, R. Nagaoka, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	Previous MBA studies converged to a combination of 7BA and 6BA structures, in terms of the target horizontal emittance of below 300 pm-rad, where the effect of anti-bends, dipole field values, and straight section lengths were investigated. Inspired by the successful lattice designs elsewhere adopting the interleaved sextupole scheme with dispersion bumps originally developed at the ESRF, the 7BA-6BA structures adopting this scheme are studied in details in parallel to those without it. The former aims at the horizontal emittance in the 200-300 pm-rad range with on and off-momentum dynamic acceptances sufficiently large for off-axis injection and good Touschek lifetime. The latter pursues the lower bound of the reachable horizontal emittance with quadrupole and sextupole strengths in the feasible range with maximum dynamic acceptance. The option of non-standard on-axis injection such as displacing the injected beam longitudinally is envisaged for the latter solutions. In both lattices, the numerical search using MOGA-based codes is employed extensively. The studies focus on the impact of linear optics and straight section lengths on the off-momentum and nonlinear properties.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK059
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MOPIK060	Applying MOGA to Search Linear Lattice in Soleil Upgrade Project	662
	H.C. Chao, P. Brunelle, R. Nagaoka SOLEIL, Gif-sur-Yvette, France
	In the community of synchrotron radiation facilities, multi-bend structure becomes the trend of the storage ring design toward lower emittance. For SOLEIL upgrade project, the 7BA-6BA hybrid structure is one of the current options. This paper puts the focus on the 7BA section. There are many degrees of freedom to tweak and many constraints to follow. Here, the idea is to search and build the linear lattice utilizing Multi-Objective Genetic Algorithm (MOGA), which is efficient dealing with higher dimension optimization problems. Within MOGA, subsidiary matchings are performed to ensure certain criteria when the new generation is bred. Delicate designs and manipulations of the objective functions are needed, in order to have a better convergence without being trapped in a local minimum. The results will be shown and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK060
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Linear and Nonlinear Optimizations of Combined 7BA-6BA Lattices for the Future Upgrade of SOLEIL

659

A. Loulergue, P. Brunelle, H.C. Chao, A. Nadji, L.S. Nadolski, R. Nagaoka, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

Previous MBA studies converged to a combination of 7BA and 6BA structures, in terms of the target horizontal emittance of below 300 pm-rad, where the effect of anti-bends, dipole field values, and straight section lengths were investigated. Inspired by the successful lattice designs elsewhere adopting the interleaved sextupole scheme with dispersion bumps originally developed at the ESRF, the 7BA-6BA structures adopting this scheme are studied in details in parallel to those without it. The former aims at the horizontal emittance in the 200-300 pm-rad range with on and off-momentum dynamic acceptances sufficiently large for off-axis injection and good Touschek lifetime. The latter pursues the lower bound of the reachable horizontal emittance with quadrupole and sextupole strengths in the feasible range with maximum dynamic acceptance. The option of non-standard on-axis injection such as displacing the injected beam longitudinally is envisaged for the latter solutions. In both lattices, the numerical search using MOGA-based codes is employed extensively. The studies focus on the impact of linear optics and straight section lengths on the off-momentum and nonlinear properties.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK059

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPIK060

Applying MOGA to Search Linear Lattice in Soleil Upgrade Project

662

H.C. Chao, P. Brunelle, R. Nagaoka
SOLEIL, Gif-sur-Yvette, France

In the community of synchrotron radiation facilities, multi-bend structure becomes the trend of the storage ring design toward lower emittance. For SOLEIL upgrade project, the 7BA-6BA hybrid structure is one of the current options. This paper puts the focus on the 7BA section. There are many degrees of freedom to tweak and many constraints to follow. Here, the idea is to search and build the linear lattice utilizing Multi-Objective Genetic Algorithm (MOGA), which is efficient dealing with higher dimension optimization problems. Within MOGA, subsidiary matchings are performed to ensure certain criteria when the new generation is bred. Delicate designs and manipulations of the objective functions are needed, in order to have a better convergence without being trapped in a local minimum. The results will be shown and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK060

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)