三次谐波超导腔高次模抑制研究

对上海同步辐射装置中超导三次谐波腔开展了高次模深度抑制研究。分析了上海光源对三次谐波腔高次模的抑制要求,用电磁场计算软件SEAFISH作高次模吸收器长度、安装位置等参数的模拟计算和优化设计,以深度抑制各有害高次模,使高次模的分路阻抗降至能满足束团不稳定性阈值的要求。用ABCI计算得到了谐波腔的高次模功耗理论值。     

Filling patterns in the SSRF storage ring

<正>There are various filling patterns in a storage ring for the users' requirements and consideration of the machine performances,such as beam lifetime,instability and chamber heating.These effects have been experimentally studied in the SSRF storage ring for typical filling patterns.Some experiment results and general trends of observations discussed in this paper.The explanations of the results are given.     

Calibration of the linear optics in the SSRF storage ring

Phase Ⅰ commissioning of the SSRF storage ring at 3.0 GeV was ended with encouraging results. Distortions and calibrations of the linear optics during the storage ring commissioning are discussed in this paper. The calibration procedure has reduced sextupole-additional focusing effects by minimizing closed orbit deviation and corrected quadrupole magnetic coefficients with the linear optics from closed orbit (LOCO) technique. After fitting the closed orbit response matrix, linear optics of the storage ring is substantially corrected, and the measured parameters agree well with the design. Four optics modes were commissioned, and relevant machine physics studies were carried out. Their results are summarized.     

Effects of insertion device on SSRF storage ring

Shanghai Synchrotron Radiation Facility （SSP.F）, one of the third generation light sources, aims to produce high brightness and/or high flux X-ray source for users; therefore insertion devices （IDs） are important magnetic elements for SSRF. In this paper, the linear perturbations due to IDs toward its storage ring lattice, such as beta function distortions, tune shifts, emittance growths, and energy spreads are estimated by using analytical formulae, and the nonlinear effects from IDs, especially dynamic aperture, are simulated by using Racetrack code. The results show that （a） the reduction of dynamic aperture from single undulator is negligible, since electron beam energy of 3.5 GeV is high and ID＇s magnetic field is low, and the beta functions in the middle of straight sections, where ID is located, are well optimized; Co） however, the reduction from single wigglers, especially super-conducting wiggler, is visible, because of its higher magnetic field; （c） effects of each ID on emittance growths and energy spreads are less than 7%.     

Lattice design and optimization of the SSRF storage ring with super-bends

In the near future,the Phase-Ⅱ beamline project of Shanghai Synchrotron Radiation Facility(SSRF)will be implemented and some dipoles in the storage ring will be replaced by high field dipoles(super-bend),so as to leave room for short straight sections.In this way,the brightness of the hard x-ray emitted from the super-bends can be enhanced,and more insertion devices can be installed.In this paper,super-bends of two lengths are discussed and the corresponding lattices are presented.     

A modeling GUI for accelerator physics of the storage ring at SSRF

In this paper, we report a MATLAB-based GUI tool, bodgui, which integrates functions of lattice editor,linear match, and nonlinear optimization, and visualized tracking functions for beam optics design. A user can switch his/ber design procedures one to another. Flexibilities are provided for adjusting or optimizing the lattice settings in commissioning or operation of the accelerators. The algorithm of the linear match and nonlinear optimization, and the GUI windows including the main functions and running status, are presented. The SSRF storage ring was employed as a test lattice. Several optics modes designed and optimized by the GUI tools were used for commissioning the storage ring. Functions of bodgui tool are machine-independent, and it can be well applied to modern light sources being built in other parts of the world.     

Monitoring the charge bunch-by-bunch for the SSRF storage ring:Development and application

Bunch charge uniformity controlling is very important for top-up operation of the storage ring. In order to monitor filling pattern and measure the bunch charge precisely, a PXI waveform digitizer-based data acquisition system has been developed to retrieve bunch charge information from BPM pickup signals. An effective sampling rate is extended to 400 GHz by waveform rebuilding technology, which overlays multi-turn data into single turn with real time sampling rate of 8 GHz. An on-line evaluation indicates that resolution and linearity of the charge measurement are better than 0.5% at input range of 0.5-12 nC.     

Optimization and comparison of accelerating cavities for the SSRF

The two kinds of cavities commolny used,the nose-coned and the bell-shaped cavities,are investigated for the RF cavity optimum design of the SSRF(Shanghai Synchrotron Radiation Facility).The maximum shunt impedance available for the former is about 45% higher than for the latter,and the latter has the stronger HOM(High order modes).     

Design of the SSRF storage ring magnet lattice

The Shanghai Synchrotron Radiation Facility (SSRF) is a proposed 3rd generation light source with 3.5 GeV in energy. It is composed of 20 DBA celis resulting in a ring that is about 10 nm-rad in emittance and 396 m in circumference, and provides 10 straight sections of 7.24 m and other 10 straight sections of 5.0 m for the inclusion of insertion devices, injection components and RF cavities. The lattice has high flexibility, and the tunes and beta func-tions can be easily adjusted within a wide range to meet the requirements for different operation modes, including high beta mode and hybrid beta mode with and/or without dispersion in straight sections. In this paper, the results of linear optics design and dynamic aperture study are presented.     

上海光源储存环光子吸收器布局设计

电子束经过储存环弯转磁铁发生偏转时,产生总功率-435 kW的同步辐射光,其中仅有一小部分被引入光束线、实验站,其余须在储存环中被光子吸收器吸收处理,并准直引出光束.本文对上海光源(SSRF0储存环同步辐射光的处理方法进行了讨论,并介绍了光子吸收器的布局、结构、性能及运行状况.     

Study of orbit stability in the SSRF storage ring

In this paper, analysis of the beam orbit stability and conceptual study of the dynamic orbit feedback in the SSRF storage ring are presented. It is shown that beam orbit position movement at the photon source points is smaller than the orbit stability requirements in horizontal plane, but exceeds the orbit stability requirements in vertical plane. A dynamic global orbit feedback system, which consists of 38 high-bandwidth air-coil correctors and 40 high-precise BPMs, is proposed to suppress the vertical beam orbit position movement. Numerical simulations show that this dynamic orbit feedback system can stabilize the vertical beam orbit position movement in the frequency range up to 100 Hz.     

Intra-beam scattering and beam lifetime in a candidate lattice of the soft X-ray diffraction-limited storage ring for the upgraded SSRF

New-generation synchrotron light sources are being designed and operated worldwide to provide brighter radiation by reducing the beam emittance to X-ray diffrac...     

上海光源储存环新注入方式

上海光源储存环的新工作模式和新装插入件会导致动力学孔径和注入效率的减小,传统的注入方式不再满足恒流注入要求。分别从改变注入方式和减小注入束流发射度两个角度解决注入对动力学孔径的需求。脉冲多极铁与凸轨相结合的注入方式可以将动力学孔径的要求降低到7 mm以下。利用斜四极铁在高能输运线上进行水平和垂直发射度互换可以将注入束流发射度降低到近1/10而降低注入点的束斑尺寸。两者都可以将注入效率提高到95%以上。二者在更小动力学孔径的情况下同时使用还可以减小脉冲多极铁的强度。     

储存环的闭合轨道畸变校正研究

在电子储存环中,弯转磁铁的场误差,转动误差和四极磁铁的横向位置偏差所科生的二极磁场分量,会导致循环电子的闭合轨道畸变（ＣＯＤ）,以ＳＳＲＦ电子储存环为例,探讨如何利用国际用加速器程序ＭＡＤ和ＲＡＣＥＴＲＡＣＫ进行第三代储存环的闭合轨道畸变校正,首先对ＳＳＲＦ电子储存环闭合轨道校正方案中的校正子和ＢＰＭ不同安放方案作了比较研究,结果表明,采用单个单元安放１０ＢＰＭ（安在六极磁铁附近）每个普通单元安装     

SSRF储存环B铁和S铁电源故障信息监控系统

根据上海光源储存环B铁和S铁电源系统的工作特点,系统故障连锁信息通过S7-200和S7-300 PLC的软件设计,完成了本地监控。基于EPICS的应用开发,实现了远程监控。介绍了EPICS系统架构,并对其硬件和软件设计中的关键技术进行了阐述。该系统具有人机交互性好、操作使用简便等优点。通过实际运行发现,系统工作稳定,达到了设计要求。     

Relation between the number of particles in a storage ring and its beam lifetime and dimensions

The authors have performed experiments to measure the lifetimes and dimensions of electron and positron beams in relation to the number of particles in the beam, in various conditions in the absence of coherent oscillations. From the results they have isolated effects due to mutual scattering by the particles in the beam. The theoretical results are in good agreement with these experiments. The authors have studied the effect of compensating ions on the characteristics of the electron beam.Translated from Atomnaya Énergiya, Vol. 22, No. 3, pp. 203–206, March, 1967.     

Thermal-hydraulic design and transient analysis of passive cooling system for CPR1000 spent fuel storage pool

This paper proposes a design of passive cooling system for CPR1000 spent fuel pool(SFP). Our design can effectively manage the SFP temperature not to exceed80 C. Then the transient analysis of the CPR1000 SFP with designed passive cooling system is carried out in station blackout(SBO) accident by the best-estimate thermal-hydraulic system code RELAP5. The simulation results show that to maintain the temperature of CPR1000 SFP under 80 C, the numbers of the SFP and air cooling heat exchangers tubes are 6627 and 19 086, respectively.The height difference between the bottom of the air cooling heat exchanger and the top of the SFP heat exchanger is3.8 m. The number of SFP heat exchanger tubes decreases as the height difference increases, while the number of the air cooling heat exchanger tubes increases. The transient analysis results show that after the SBO accident, a stable natural cooling circulation is established. The surface temperature of CPR1000 SFP increases continually until 80 C, which indicates that the design of the passive air cooling system for CPR1000 SFP is capable of removing the decay heat to maintain the temperature of the SFP around 80 C after losing the heat sink.     

锁相法测量BEPC储存环自由振荡频率

BEPC储存环自由振荡频率测量系统包括前端电子学系统，测量系统和激励系统。介绍了采用锁相法的BEPC储存环自由振荡频率测量系统。     

Survey of experiments and code development for the passive residual heat removal system of PWR in China

Three different kinds of experiments and their typical results are surveyed for the passive residual heat removal system (PRHRS) of PWR performed in Nuclear Power Institute of China (NPIC) recent ten years. The typical results of MISAP. a special code for PWR passive residual heat removal system developed and assessed by NPIC,are also described briefly in this paper.     

Altitude and intensity characteristics of parametric instability excited by an HF pump wave near the fifth electron harmonic

An ionospheric heating experiment involving an O mode pump wave was carried out at European Incoherent Scatter Scientific Association site in Tromsφ.The observation of the ultra high frequency radar illustrates the systematic variations of the enhanced ion line and plasma line in altitude and intensity as a function of the pump frequency.The analysis shows that those altitude variations are due to the thermal effect,and the intensity variations of the enhanced ion line are dependent on whether or not the enhanced ion acoustic wave satisfy the Bragg condition of radar.Moreover,a prediction that if the enhancement in electron temperature is suppressed,those systematic variations will be absent,is given.