IPAC2017 - List of Authors (Li, J.)

Paper	Title	Page
TUPIK042	Solenoid Alignment for the SRF Photoinjector of BERLinPro at HZB	1778
	G. Kourkafas, A. Jankowiak, T. Kamps, J. Li, J. Völker HZB, Berlin, Germany M. Schebek Humboldt University Berlin, Berlin, Germany
	The Berlin Energy Recovery Linac Prototype (BERLinPro) at Helmholtz Zentrum Berlin (HZB) aims to deliver a continuous-wave (cw) electron beam of high average current (100 mA) and brilliance (normalized emittance below 1 mm mrad). The achievement of these demanding goals depends significantly on the performance of the electron source, a superconducting RF (SRF) photoinjector. A critical component for the quality of the generated beam is the superconducting solenoid magnet. In order to optimize its operation and minimize parasitic contributions, special attention has been given to the precise alignment of this element using a hexapod mover. Due to the strict limitations inside a cryostat, a complex coupling between the solenoid in vacuum and the hexapod in air has been realized, requiring sophisticated software and hardware mechanisms to prevent collisions. Along with this setup, the developed beam-based alignment procedure and its performance are demonstrated in this article.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK042
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WEPAB006	Performance Improvements of the BESSY II Storage Ring by Optimizing the Phase Acceptance	2571
	P. Kuske, J. Li HZB, Berlin, Germany
	Linear optics modifications in order to improve injec-tion efficiency and for the installation of two IDs in one straight section demand an optimization of the sextupole correction scheme. Four harmonic sextupole families were sufficient with the earlier 8-fold symmetric lattice. Today there are ten families of harmonic sextupole mag-nets in addition to the three families of chromatic sextu-poles. This paper describes our experimental approach to find better settings for these harmonic sextupoles based on the direct optimization of the injection efficiency with a longitudinal phase offset between storage ring and the injector - in our case a booster synchrotron. As demon-strated in the paper, the resulting improvement of the phase acceptance of the ring leads to increased momen-tum acceptance by suppressing 3rd order non-systematic resonances. This increases not only the injection effi-ciency for long bunches but also the Touschek lifetime, the largest contribution to the overall lifetime of low emittance storage rings.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB006
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THPAB008	Particle Swarm Optimization Algorithm Applied in Online Commissioning at the MLS and BESSY II	3700
	J. Li, J. Feikes, P. Goslawski, M. Ries HZB, Berlin, Germany
	Particle Swarm Optimization (PSO) is a population based optimization technique inspired by the social behaviour of bird flocking. This algorithm has been successfully used for beam dynamics simulation due to its excellent capability to deal with large-dimensional optimization problems. At the MLS and BESSY II PSO was first successfully applied to improve the lifetime by 20~30% within only 10 iterations respectively. Now the PSO has been implemented as a multifunctional online optimizer to improve the machine performance. This paper presents some results of online experiments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB008
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Paper

Title

Page

Solenoid Alignment for the SRF Photoinjector of BERLinPro at HZB

1778

G. Kourkafas, A. Jankowiak, T. Kamps, J. Li, J. Völker
HZB, Berlin, Germany
M. Schebek
Humboldt University Berlin, Berlin, Germany

The Berlin Energy Recovery Linac Prototype (BERLinPro) at Helmholtz Zentrum Berlin (HZB) aims to deliver a continuous-wave (cw) electron beam of high average current (100 mA) and brilliance (normalized emittance below 1 mm mrad). The achievement of these demanding goals depends significantly on the performance of the electron source, a superconducting RF (SRF) photoinjector. A critical component for the quality of the generated beam is the superconducting solenoid magnet. In order to optimize its operation and minimize parasitic contributions, special attention has been given to the precise alignment of this element using a hexapod mover. Due to the strict limitations inside a cryostat, a complex coupling between the solenoid in vacuum and the hexapod in air has been realized, requiring sophisticated software and hardware mechanisms to prevent collisions. Along with this setup, the developed beam-based alignment procedure and its performance are demonstrated in this article.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK042

Export •

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

WEPAB006

Performance Improvements of the BESSY II Storage Ring by Optimizing the Phase Acceptance

2571

P. Kuske, J. Li
HZB, Berlin, Germany

Linear optics modifications in order to improve injec-tion efficiency and for the installation of two IDs in one straight section demand an optimization of the sextupole correction scheme. Four harmonic sextupole families were sufficient with the earlier 8-fold symmetric lattice. Today there are ten families of harmonic sextupole mag-nets in addition to the three families of chromatic sextu-poles. This paper describes our experimental approach to find better settings for these harmonic sextupoles based on the direct optimization of the injection efficiency with a longitudinal phase offset between storage ring and the injector - in our case a booster synchrotron. As demon-strated in the paper, the resulting improvement of the phase acceptance of the ring leads to increased momen-tum acceptance by suppressing 3rd order non-systematic resonances. This increases not only the injection effi-ciency for long bunches but also the Touschek lifetime, the largest contribution to the overall lifetime of low emittance storage rings.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB006

Export •

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

THPAB008

Particle Swarm Optimization Algorithm Applied in Online Commissioning at the MLS and BESSY II

3700

J. Li, J. Feikes, P. Goslawski, M. Ries
HZB, Berlin, Germany

Particle Swarm Optimization (PSO) is a population based optimization technique inspired by the social behaviour of bird flocking. This algorithm has been successfully used for beam dynamics simulation due to its excellent capability to deal with large-dimensional optimization problems. At the MLS and BESSY II PSO was first successfully applied to improve the lifetime by 20~30% within only 10 iterations respectively. Now the PSO has been implemented as a multifunctional online optimizer to improve the machine performance. This paper presents some results of online experiments.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB008

Export •

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