快速轨道反馈(Fast Orbital Feedback,FOFB)系统是影响高能同步辐射光源(High Energy Photon Source,HEPS)轨道稳定性的重要因素之一,在设计时应尽可能提高FOFB系统的有效反馈带宽。基于该需求,为HEPS的FOFB系统设计了两层环路集中计算...快速轨道反馈(Fast Orbital Feedback,FOFB)系统是影响高能同步辐射光源(High Energy Photon Source,HEPS)轨道稳定性的重要因素之一,在设计时应尽可能提高FOFB系统的有效反馈带宽。基于该需求,为HEPS的FOFB系统设计了两层环路集中计算式的系统网络拓扑结构,并在此基础上设计完成了FOFB系统信号传输链路的可编程阵列逻辑(Field Programmable Gate Array,FPGA)固件算法逻辑,内容包括束流位置获取、环路数据传输、FOFB算法、电源控制接口以及系统测试等多个部分。经实验室测试验证,当前结构下的FOFB系统总延迟时间约为140μs,满足HEPS装置对FOFB系统有效反馈带宽的需求。展开更多
Model independent analysis, which was developed for high precision and fast beam dynamics analysis, is a promising diagnostic tool for modern accelerators. We implemented a series of methods to analyze the turn-by-tur...Model independent analysis, which was developed for high precision and fast beam dynamics analysis, is a promising diagnostic tool for modern accelerators. We implemented a series of methods to analyze the turn-by-turn BPM data. Green＇s functions corresponding to the local transfer matrix elements R12 or R34 are extracted from BPM data and fitted with the model lattice using least-square fitting. Here, we report experimental results obtained from analyzing the transverse motion of a beam in the storage ring at the Advanced Photon Source. BPM gains and uncoupled optics parameters are successfully determined. Quadrupole strengths are adjusted for fitting but can not be uniquely determined in general due to an insufficient number of BPMs.展开更多
The robust conjugate direction search （RCDS） method has high tolerance to noise in beam experiments. It has been demonstrated that this method can be used to optimize the machine performance of a light source online...The robust conjugate direction search （RCDS） method has high tolerance to noise in beam experiments. It has been demonstrated that this method can be used to optimize the machine performance of a light source online. In our study, taking BEPCII as an example, the feasibility of online tuning of the luminosity in a circular collider is explored, through numerical simulation and preliminary online experiments. It is shown that the luminosity that is artificially decreased by a deviation of beam orbital offset from optimal trajectory can be recovered with this method.展开更多
The existing linear coupling theory and representation method are introduced briefly. The socalled local and global coupling is discussed in more detail. The vertical orbit distortion excited by a horizontal corrector...The existing linear coupling theory and representation method are introduced briefly. The socalled local and global coupling is discussed in more detail. The vertical orbit distortion excited by a horizontal corrector is represented with the coupling parameters at the corrector and the observation point. The formula is used to measure the coupling in BEPC II. In order to correct the coupling, vertical correctors are used to change the vertical orbit through sextupoles by a least square method. We also introduce and review other frequently used coupling measurement/tuning methods used in our machine.展开更多
文摘快速轨道反馈(Fast Orbital Feedback,FOFB)系统是影响高能同步辐射光源(High Energy Photon Source,HEPS)轨道稳定性的重要因素之一,在设计时应尽可能提高FOFB系统的有效反馈带宽。基于该需求,为HEPS的FOFB系统设计了两层环路集中计算式的系统网络拓扑结构,并在此基础上设计完成了FOFB系统信号传输链路的可编程阵列逻辑(Field Programmable Gate Array,FPGA)固件算法逻辑,内容包括束流位置获取、环路数据传输、FOFB算法、电源控制接口以及系统测试等多个部分。经实验室测试验证,当前结构下的FOFB系统总延迟时间约为140μs,满足HEPS装置对FOFB系统有效反馈带宽的需求。
基金Supported by the Chinese National Foundation of Natural Sciences(111100512108)National Sciences Foundation of Chinese(10725525)
文摘Model independent analysis, which was developed for high precision and fast beam dynamics analysis, is a promising diagnostic tool for modern accelerators. We implemented a series of methods to analyze the turn-by-turn BPM data. Green＇s functions corresponding to the local transfer matrix elements R12 or R34 are extracted from BPM data and fitted with the model lattice using least-square fitting. Here, we report experimental results obtained from analyzing the transverse motion of a beam in the storage ring at the Advanced Photon Source. BPM gains and uncoupled optics parameters are successfully determined. Quadrupole strengths are adjusted for fitting but can not be uniquely determined in general due to an insufficient number of BPMs.
基金Supported by National Natural Science Foundation of China(11475202,11405187)Youth Innovation Promotion Association of Chinese Academy of Sciences(2015009)
文摘The robust conjugate direction search （RCDS） method has high tolerance to noise in beam experiments. It has been demonstrated that this method can be used to optimize the machine performance of a light source online. In our study, taking BEPCII as an example, the feasibility of online tuning of the luminosity in a circular collider is explored, through numerical simulation and preliminary online experiments. It is shown that the luminosity that is artificially decreased by a deviation of beam orbital offset from optimal trajectory can be recovered with this method.
基金Supported by National Natural Science Foundation of China(10805051,10725525)
文摘The existing linear coupling theory and representation method are introduced briefly. The socalled local and global coupling is discussed in more detail. The vertical orbit distortion excited by a horizontal corrector is represented with the coupling parameters at the corrector and the observation point. The formula is used to measure the coupling in BEPC II. In order to correct the coupling, vertical correctors are used to change the vertical orbit through sextupoles by a least square method. We also introduce and review other frequently used coupling measurement/tuning methods used in our machine.
