射频四极场加速器(Radio Frequency Quadrupole,RFQ)广泛应用于质子加速器装置中,高频率、紧凑型RFQ的发展可以推动质子加速器装置的小型化,同时也面临调谐困难的问题。紧凑型RFQ的性能对腔体尺寸的敏感度高,基于理论物理特性的传统调...射频四极场加速器(Radio Frequency Quadrupole,RFQ)广泛应用于质子加速器装置中,高频率、紧凑型RFQ的发展可以推动质子加速器装置的小型化,同时也面临调谐困难的问题。紧凑型RFQ的性能对腔体尺寸的敏感度高,基于理论物理特性的传统调谐算法难以取得良好效果,而基于腔体实际物理特性的调谐算法则可以解决紧凑型RFQ的调谐难点。本文提出了一种基于响应矩阵和最小二乘法的调谐算法,该算法可以限定求解的范围,避免计算结果超出调谐器可调谐范围的问题;为二极场分量赋予权重,可以高效地降低二极场误差,解决二极场分量难以调谐的问题。根据新的调谐算法分别在模拟环境下的RFQ样机上完成了调谐实验,在搭建的测量平台获得的结果显示:初始状态下二、四极场误差分别为24.09%和1.57%,经过5次调谐后两者误差分别降为2.33%和1.39%,验证了调谐算法的有效性。该调谐算法具有普适性,也可以用于其他频率的RFQ,将来还可以促进质子加速器装置的小型化,推动医用质子装置的普及。展开更多
自由电子激光(Free Electron Laser,FEL)对电子束的发射度有极高的要求。近年来,可产生短电子束团并且具有高亮度性质的电子枪,是研发高性能FEL的核心部分,也是重要挑战与研究热点。一个很有前景的方向是提高微波电子枪(RF电子枪)内的...自由电子激光(Free Electron Laser,FEL)对电子束的发射度有极高的要求。近年来,可产生短电子束团并且具有高亮度性质的电子枪,是研发高性能FEL的核心部分,也是重要挑战与研究热点。一个很有前景的方向是提高微波电子枪(RF电子枪)内的加速梯度。提高现有电子枪的梯度,需要对电子枪微波场的优化、螺线管的设计和束流初始分布设置有全新的方案。为了解决这个需要多参数协调优化的问题,本文基于上海软X射线自由电子激光装置,率先从空间电荷力、加速电场与发射度补偿的角度,系统地分析和探索了高梯度C波段光阴极电子枪升级的设计与优化的方法。用ASTRA程序,对电子枪内不同电场强度对束流动力学的影响进行了模拟。详细分析了发射度补偿原理,对螺线管的主副螺线圈电流比进行优化,并研究了初始束团分布对发射度的影响。模拟结果表明:采用优化的电场强度、螺线管的主副螺线圈电流比与初始束团分布,电子枪输出束团的发射度有显著改善,满足FEL光源对于电子枪低发射度的要求。展开更多
The research and development of a C-band (5712 MHz) high gradient traveling-wave accelerating structure has been in progress for some years at the Shanghai Institute of Applied Physics, Chinese Academy of Sciences. Co...The research and development of a C-band (5712 MHz) high gradient traveling-wave accelerating structure has been in progress for some years at the Shanghai Institute of Applied Physics, Chinese Academy of Sciences. Conceptual design of the accelerating structure has been accomplished, and verified by cold testing an experimental model. The first prototype structure is now ready for high RF power tests. To develop a robust high gradient C-band accelerating structure, an optimized constant gradient structure with a 4 /5 operating mode for future X-ray Free Electron Laser facilities is proposed in this paper. This scheme can improve the breakdown stability and beam quality. The high power RF system, four operating modes and disk iris shape are analyzed and optimized.展开更多
Research and design of a C-band (5712 MHz) high-gradient traveling-wave accelerating structure is being carried out at Shanghai Institute of Applied Physics,Chinese Academy of Sciences.The structure consists of 53 reg...Research and design of a C-band (5712 MHz) high-gradient traveling-wave accelerating structure is being carried out at Shanghai Institute of Applied Physics,Chinese Academy of Sciences.The structure consists of 53 regular disk-loaded cells and two waveguide couplers,and its length is about 1 m.This paper presents a design method for the accelerating structure,an experimental model and the preliminary results of an RF cold test of the model structure.展开更多
Assisted by the bead pull technique,nonresonant perturbation theory is applied for measuring and tuning the field of the linac accelerating structure.The method is capable of making non-touching amplitude and phase me...Assisted by the bead pull technique,nonresonant perturbation theory is applied for measuring and tuning the field of the linac accelerating structure.The method is capable of making non-touching amplitude and phase measurements,real time mismatch feedback and field tuning.Some key considerations of the measurement system and of a C-band traveling-wave structure are discussed,and the bead pull measurement and the tuning of the C-band traveling-wave linac accelerating structure are presented at last.展开更多
文摘射频四极场加速器(Radio Frequency Quadrupole,RFQ)广泛应用于质子加速器装置中,高频率、紧凑型RFQ的发展可以推动质子加速器装置的小型化,同时也面临调谐困难的问题。紧凑型RFQ的性能对腔体尺寸的敏感度高,基于理论物理特性的传统调谐算法难以取得良好效果,而基于腔体实际物理特性的调谐算法则可以解决紧凑型RFQ的调谐难点。本文提出了一种基于响应矩阵和最小二乘法的调谐算法,该算法可以限定求解的范围,避免计算结果超出调谐器可调谐范围的问题;为二极场分量赋予权重,可以高效地降低二极场误差,解决二极场分量难以调谐的问题。根据新的调谐算法分别在模拟环境下的RFQ样机上完成了调谐实验,在搭建的测量平台获得的结果显示:初始状态下二、四极场误差分别为24.09%和1.57%,经过5次调谐后两者误差分别降为2.33%和1.39%,验证了调谐算法的有效性。该调谐算法具有普适性,也可以用于其他频率的RFQ,将来还可以促进质子加速器装置的小型化,推动医用质子装置的普及。
文摘自由电子激光(Free Electron Laser,FEL)对电子束的发射度有极高的要求。近年来,可产生短电子束团并且具有高亮度性质的电子枪,是研发高性能FEL的核心部分,也是重要挑战与研究热点。一个很有前景的方向是提高微波电子枪(RF电子枪)内的加速梯度。提高现有电子枪的梯度,需要对电子枪微波场的优化、螺线管的设计和束流初始分布设置有全新的方案。为了解决这个需要多参数协调优化的问题,本文基于上海软X射线自由电子激光装置,率先从空间电荷力、加速电场与发射度补偿的角度,系统地分析和探索了高梯度C波段光阴极电子枪升级的设计与优化的方法。用ASTRA程序,对电子枪内不同电场强度对束流动力学的影响进行了模拟。详细分析了发射度补偿原理,对螺线管的主副螺线圈电流比进行优化,并研究了初始束团分布对发射度的影响。模拟结果表明:采用优化的电场强度、螺线管的主副螺线圈电流比与初始束团分布,电子枪输出束团的发射度有显著改善,满足FEL光源对于电子枪低发射度的要求。
基金supported by the Program of the Shanghai Subject Chief Scientist-Natural Science Foundation (08XD1405400)
文摘The research and development of a C-band (5712 MHz) high gradient traveling-wave accelerating structure has been in progress for some years at the Shanghai Institute of Applied Physics, Chinese Academy of Sciences. Conceptual design of the accelerating structure has been accomplished, and verified by cold testing an experimental model. The first prototype structure is now ready for high RF power tests. To develop a robust high gradient C-band accelerating structure, an optimized constant gradient structure with a 4 /5 operating mode for future X-ray Free Electron Laser facilities is proposed in this paper. This scheme can improve the breakdown stability and beam quality. The high power RF system, four operating modes and disk iris shape are analyzed and optimized.
基金supported by the Program of Shanghai Subject Chief Scientist-Natural Science Foundation (Key Program)(08XD14054)
文摘Research and design of a C-band (5712 MHz) high-gradient traveling-wave accelerating structure is being carried out at Shanghai Institute of Applied Physics,Chinese Academy of Sciences.The structure consists of 53 regular disk-loaded cells and two waveguide couplers,and its length is about 1 m.This paper presents a design method for the accelerating structure,an experimental model and the preliminary results of an RF cold test of the model structure.
基金supported by Program of Shanghai Subject Chief Scientist and Natural Science Foundation of China (key program) (Grant No. 08XD1405400)
文摘Assisted by the bead pull technique,nonresonant perturbation theory is applied for measuring and tuning the field of the linac accelerating structure.The method is capable of making non-touching amplitude and phase measurements,real time mismatch feedback and field tuning.Some key considerations of the measurement system and of a C-band traveling-wave structure are discussed,and the bead pull measurement and the tuning of the C-band traveling-wave linac accelerating structure are presented at last.
