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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. 相似文献
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There are 140 beam position monitors (BPMs) in the Shanghai Synchrotron Radiation Facility (SSRF) storage ring used for measuring the closed orbit. As the BPM pickup electrodes are assembled directly on the vacuum chamber, it is important to calibrate the electrical center offset of the BPM to an adjacent quadrupole magnetic center. A beam based alignment (BBA) method which varies individual quadrupole magnet strength and observes its effects on the orbit is used to measure the BPM offsets in both the horizontal and vertical planes. It is a completely automated technique with various data processing methods. There are several parameters such as the strength change of the correctors and the quadrupoles which should be chosen carefully in real measurement. After several rounds of BBA measurement and closed orbit correction, these offsets are set to an accuracy better than 10 μm. In this paper we present the method of beam based calibration of BPMs, the experimental results of the SSRF storage ring, and the error analysis. 相似文献
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In this paper, we present a rule to improve the nonlinear solution with frequency map analysis (FMA), and without frequently revisiting the optimization algorithm. Two aspects of FMA are emphasized. The first one is the tune shift with amplitude, which can be used to improve the solution of harmonic sextupoles, and thus obtain a large dynamic aperture. The second one is the tune diffusion rate, which can be used to select a quiet tune. Application of these ideas is carried out in the storage ring of the Shanghai Synchrotron Radiation Facility (SSRF), and the detailed processes, as well as better solutions, are presented in this paper. Discussions about the nonlinear behaviors of off-momentum particles are also presented. 相似文献
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As the dipoles of SSRF booster are powered in series, the magnet field error varies from magnet to magnet and results in bad beam quality. Sorting and installing magnets according to the measured field errors so that the errors on different magnets are partially compensated with each other, has been the easiest way in many cases to reduce the detrimental effects of the errors without introducing complications. Based on the magnet field measurement results, we investigated and implemented the sorting of dipoles using a method mixed by local cancellation and simulated annealing, and it's found to be quite effective. 相似文献
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上海光源是我国刚刚建成的一台第三代中能同步辐射光源。为使得上海光源能够严格工作在设计状态下, 在调试过程中进行了一系列线性模型的校正, 主要包括闭轨校正、 基于束流准直(BBA)校正、 LOCO参数校正和线性耦合校正。经过反复的线性模型校正以后, 上海光源储存环的闭轨畸变均方根误差在水平和垂直两个方向可以分别控制到50和60 μm的水平, 包络函数畸变和色散函数畸变都可以控制到小于1%的状态, 工作点和束流发射度基本上校正到了设计值。线性耦合校正能够方便地将储存环的耦合度从0.02%调节到2%左右。调试结果表明, 上海光源采取的这一套线性模型校正方法, 能够有效地将上海光源的工作状态校正到设计状态, 并且为其他模式的调节奠定了基础。In the commissioning stage of Shanghai Synchrotron Radiation Facility(SSRF) storage ring, several methods were used to correct the linear optics. Beam Based Alignment(BBA) was used for BPM\|Quadrupole offsets measurement; Response matrix was used for orbit correction; LOCO was used for linear optics fitting, and quadrupoles strength were adjusted to correction the beta function; coupling was measured and corrected by skew quadrupoles. After correction, closed orbit are reduced to 50/60 μm in hortizontal and vertical plane; β beating and dispersion errors are less than 1%; betatron tune and emmittance are closed to the design value; betatron coupling also can be adjusted from 0.02% to 2%. These methods have been proved to be useful for storage ring calibrations, with the help of these methods, SSRF storage ring can be tuned to the design model and other model easily. 相似文献
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Design and first commissioning of a new mode with lower emittance in the SSRF storage ring 总被引:1,自引:0,他引:1
A new mode is designed with an emittance of 2.47 nm-rad at 3.0 GeV beam energy, lower than the nominal mode of the Shanghai Synchrotron Radiation Facility (SSRF) storage ring. Details of the linear optics design and the nonlinear optimization are presented in this paper. During Phase I commissioning of the storage ring we tested the new optics mode and some expected results were obtained. After restoring the linear optics by means of the linear optics with closed orbit technique, the main parameters of the real machine agree well with the designed values and the injection efficiency and beam lifetime are acceptable. 相似文献