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Optimization of magnet sorting in a storage ring using genetic algorithms

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Chinese Physics C 2013年第12期37卷 98-104页

作者：陈佳王琳李为民高巍巍 National Synchrotron Radiation Laboratory University of Science and Technology of China

In this paper, the genetic algorithms are applied to the optimization problem of magnet sorting in an electron storage ring, according to which the objectives are set so that the closed orbit distortion and beta beating can be minimized and the dynamic aperture maximized. The sorting of dipole, quadrupole and sextupole magnets is optimized while the optimization results show the power of the application of genetic algorithms in magnet sorting.

关键词： storage ring magnet sorting closed orbit distortion beta beating dynamic aperture genetic algorithms

Study of magnetic hysteresis effects in a storage ring using precision tune measurement

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Chinese Physics C 2016年第12期40卷 133-142页

作者： Wei Li Hao Hao Stepan F. Mikhailov Wei Xu Jing-Yi Li Wei-Min Li Ying. K. Wu National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei 230029 Chin Triangle University Nuclear Laboratory/Physics Department Duke University Durham 27705 USA

With the advances in accelerator science and technology in recent decades, the accelerator commumty has focused on the development of next-generation light sources, for example diffraction-limited storage rings （DLSRs）, which require precision control of the electron beam energy and betatron tunes. This work is aimed at understanding magnet hysteresis effects on the electron beam energy and lattice focusing in circular accelerators, and developing new methods to gain better control of these effects. In this paper, we will report our recent experimental study of the magnetic hysteresis effects and their impacts on the Duke storage ring lattice using the transverse feedback based precision tune measurement system. The major magnet hysteresis effects associated with magnet normalization and lattice ramping are carefully studied to determine an effective procedure for lattice preparation while maintaining a high degree of reproducibility of lattice focusing. The local hysteresis effects are also studied by measuring the betatron tune shifts which result from adjusting the setting of a quadrupole. A new technique has been developed to precisely recover the focusing strength of the quadrupole by hysteresis effect. returning it to a proper setting to overcome the local

关键词： magnetic hysteresis storage ring betatron tune magnet normalization

A design strategy of achievable linear optics for a complex storage ring lattice

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Chinese Physics C 2010年第7期34卷 1009-1015页

作者：田顺强 Shanghai Institute of Applied Physics Chinese Academy of Sciences

A design strategy is discussed in this paper,and it provides much convenience for effectively exploring achievable linear optics and globally investigating the flexibility of a complex lattice with super-periodicity.A matching method of fractional steps,which means separately finding the standard cell setting and the matching cell setting,is adopted to simplify the complexity of the linear beam optics design in the complex *** multi-objective genetic algorithm is used to find most of all the stable linear optics,and reach a target solution after multi-generational propagation,both in the standard cell and the matching cell.A fitting algorithm with gradient information is used to restore the periodicity and symmetry of the lattice,and finely adjust the linear optics for further *** design strategy is applied in the Shanghai Synchrotron Radiation Facility（SSRF） storage ring,and the results are presented.

关键词： storage ring linear optics low-αc multbobjective genetic algorithm

Tune optimization of the third generation light source storage ring based on Frequency Map Analysis

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Chinese Physics C 2009年第3期33卷 224-231页

作者：田顺强刘桂民李浩虎后接张文志 Shanghai Institute of Applied Physics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

Tune optimization is necessary to optimize the nonlinearity of the third generation light source storage ring. In this paper we summarize the common strategies for choosing a tune and discuss tune op- timization. Frequency Map Analysis （FMA） is applied as a tune scanning tool to reveal information about nonlinear resonances and guide the tune optimization. The Shanghai Synchrotron Radiation Facility （SSRF） storage ring is taken as a test lattice, and the optimum solutions are presented in this paper. Moreover, the third order regular structural resonances excited by sextupoles are particularly investigated, and it is found that these resonances distort the tune shifts with amplitude and show a stop-band like the linear structural resonances.

关键词： storage ring tune FMA structural resonance stop-band

Compensation for booster leakage field in the Duke storage ring

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Chinese Physics C 2017年第1期41卷 173-179页

作者：李为郝浩 Stepan F.Mikhailov Victor Popov 李为民吴英 National Synchrotron Radiation Laboratory University of Science and Technology of China Triangle University Nuclear Laboratory/Physics Department Duke University

The High Intensity Gamma-ray Source（HIGS） at Duke University is an accelerator-driven Compton gamma-ray source, providing high flux gamma-ray beam from 1 MeV to 100 MeV for photo-nuclear physics *** HIGS facility operates three accelerators, a linac pre-injector（0.16 GeV）, a booster injector（0.16—1.2 GeV）,and an electron storage ring（0.24—1.2 GeV）. Because of the proximity of the booster injector to the storage ring, the magnetic field of the booster dipoles close to the ring can significantly alter the closed orbit in the storage ring being operated in the low energy region. This type of orbit distortion can be a problem for certain precision experiments which demand a high degree of energy consistency of the gamma-ray beam. This energy consistency can be achieved by maintaining consistent aiming of the gamma-ray beam, and therefore a steady electron beam orbit and angle at the Compton collision point. To overcome the booster leakage field problem, we have developed an orbit compensation scheme. This scheme is developed using two fast orbit correctors and implemented as a feedforward which is operated transparently together with the slow orbit feedback system. In this paper, we will describe the development of this leakage field compensation scheme, and report the measurement results, which demonstrate the effectiveness of the scheme.

关键词： field compensation feedforward storage ring beam orbit

Stabilization of betatron tune in Indus-2 storage ring

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Chinese Physics C 2014年第6期38卷 79-85页

作者： Saroj Jena S.Yadav R.K.Agrawal A.D.Ghodke Pravin Fatnani T.A.Puntambekar Raja Ramanna Centre for Advanced Technology Indore India

Indus-2 is a synchrotron radiation source that is operational at RRCAT, Indore, India. It is essentially pertinent in any synchrotron radiation facility to store the electron beam without beam loss. During the day to day operation of Indus-2 storage ring, difficulty was being faced in accumulating higher beam current. After examination, it was found that the working point was shifting from its desired value during accumulation. For smooth beam accumulation, a fixed desired tune in both horizontal and vertical plane plays a significant role in avoiding beam loss via the resonance process. This required a betatron tune feedback system to be put in the storage ring. After putting ON this feedback, the beam accumulation was smooth. The details of this feedback and its working principle are described in this paper.

关键词： working point tune feedback storage ring

Improved nonlinear optimization in the storage ring of the modern synchrotron radiation light source

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Chinese Physics C 2009年第1期33卷 65-73页

作者：田顺强刘桂民后接陈光玲陈森玉 Shanghai Institute of Applied Physics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences Institute of High Energy Physics Chinese Academy of Sciences

In the storage ring of the third generation light sources, nonlinear optimization is an indispensable course in order to obtain ample dynamic acceptances and to reach high injection efficiency and long beam lifetime, especially in a low emittance lattice. An improved optimization algorithm based on the single resonance approach, which takes relative weight and initial Harmonic Sextupole Integral Strength （HSIS） as search variables, is discussed in this paper. Applications of the improved method in several test lattices are presented. Detailed analysis of the storage ring of the Shanghai Synchrotron Radiation Facility （SSRF） is particularly emphasized. Furthermore, cancellation of the driving terms is investigated to reveal the physical mechanism of the harmonic sextupole compensation. Sensitivity to the weight and the initial HSIS as well as dependence of the optimum solution on the convergent factor is analyzed.

关键词： storage ring nonlinear optimization harmonic compensation single resonance approach

Low emittance lattice for the storage ring of the Turkish Light Source Facility TURKAY

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Chinese Physics C 2015年第6期39卷 94-97页

作者： Z.Nergiz A.Aksoy Nigde University Department of Physics Faculty of Letter and Science Ankara University Institute of Accelerator Technology

The TAC （Turkish Accelerator Center） project aims to build an accelerator center in Turkey. The first stage of the project is to construct an Infra-Red Free Electron Laser （IR-FEL） facility. The second stage is to build a synchrotron radiation facility named TURKAY, which is a third generation synchrotron radiation light source that aims to achieve a high brilliance photon beam from a low emittance electron beam at 3 GeV. The electron beam parameters are highly dependent on the magnetic lattice of the storage ring. In this paper a low emittance storage ring for TURKAY is proposed and the beam dynamic properties of the magnetic lattice are investigated.

关键词： TURKAY storage ring beam dynamics synchrotron radiation

A slow orbit feedback algorithm based on expanded responsematrix for SSRF storage ring

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Radiation Detection Technology and Methods 2022年第4期6卷 540-543页

作者： Bocheng Jiang Hanghua Xu Kun Wang Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201204China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of the Chinese Academy of Sciences Beijing 100049China

Background Most of the global orbit feedback algorithms in storage rings are based on response matrix(RM)singular value decomposition ***,the RM is the orbit distortion along the ring responding to the steering magnet *** those methods RF frequency feedback is in a separated *** and Results In this paper,the response matrix is expanded to the orbit distortion caused by the RF frequency *** this expanded RM,the orbit correction via steering magnet changes and RF frequency adjustment can be accomplished in one *** commissioning results are carried out showing that the algorithm works stably.

关键词： Slow orbit feedback storage ring Expanded response matrix