中国科学院高能物理研究所提出了ERL-FEL(Energy recovery linac-Free electron laser)"一机两用"的概念,通过同一直线加速器将能量回收加速器(Energy recovery linac,ERL)和自由电子激光(Free electron laser,FEL)结合到一...中国科学院高能物理研究所提出了ERL-FEL(Energy recovery linac-Free electron laser)"一机两用"的概念,通过同一直线加速器将能量回收加速器(Energy recovery linac,ERL)和自由电子激光(Free electron laser,FEL)结合到一起。本文讨论ERL-FEL两用实验装置主体屏蔽设计中,利用离散抽样的方法实现多个损失源项的整合,在同一FLUKA用户程序中实现多源抽样,并将蒙特卡罗计算结果与各源项独立处理的累积结果进行对比。计算表明,两者的结果吻合较好。基于束流损失源项整体建模的方法适用于其他小型直线加速器的整体屏蔽计算,可方便在其他装置上扩展应用。展开更多
The energy recovery linac test facility(ERL-TF), which is a compact ERL-FEL(free electron laser)two-purpose machine, was proposed at the Institute of High Energy Physics, Beijing. As one important component of the ERL...The energy recovery linac test facility(ERL-TF), which is a compact ERL-FEL(free electron laser)two-purpose machine, was proposed at the Institute of High Energy Physics, Beijing. As one important component of the ERL-TF, the photo-injector that started with a photocathode direct-current gun has been designed. In this paper, optimization of the injector beam dynamics in low-charge operation mode is performed with iterative scans using Impact-T. In addition, the dependencies between the optimized beam quality and the initial offset at cathode and element parameters are investigated. The tolerance of alignment and rotation errors is also analyzed.展开更多
Generally, the Energy Recovery Linac (ERL) needs specially designed high current superconducting RF cavities. In this paper, the threshold current of beam breakup for compact ERL facilities with 9-cell Tesla type cavi...Generally, the Energy Recovery Linac (ERL) needs specially designed high current superconducting RF cavities. In this paper, the threshold current of beam breakup for compact ERL facilities with 9-cell Tesla type cavities are investigated. The results show that it is feasible to adopt the 9-cell Tesla cavity for compact ERL test facilities with just a few cavities and beam current around 10 mA.展开更多
Both the energy recovery linac (ERL) and the free electron laser (FEL) are considered to be candidate fourth generation light sources. It is proposed to combine an FEL into an ERL facility to integrate the advantages ...Both the energy recovery linac (ERL) and the free electron laser (FEL) are considered to be candidate fourth generation light sources. It is proposed to combine an FEL into an ERL facility to integrate the advantages of both, and to realize a compact two-purpose light source. A test facility to verify this principle is being designed at the Institute of High Energy Physics, Beijing. One main concern is the beam breakup (BBU) instability which limits the available beam current. To this end, we developed a numerical simulation code to calculate the BBU threshold, which is found to have only a small reduction even in a high-FEL-bunch-charge operation mode, compared with that in the case with ERL bunches only. However, even with the ERL beam current far below the BBU threshold, we observed a fluctuation of the central orbit of the ERL bunches in the presence of an FEL beam. We then present a physical model of BBU and understand the mechanism of the orbit-fluctuation in an ERL-FEL two-purpose machine. We found that by choosing an appropriate FEL bunch repetition rate, the central orbit fluctuation amplitude can be well controlled.展开更多
The energy recovery linac test facility(ERL-TF),a compact ERL-FEL(free electron laser)two-purpose machine,has been proposed at the Institute of High Energy Physics,Beijing.As one important component of the ERL-TF,the ...The energy recovery linac test facility(ERL-TF),a compact ERL-FEL(free electron laser)two-purpose machine,has been proposed at the Institute of High Energy Physics,Beijing.As one important component of the ERL-TF,the photo-injector was designed and preliminarily optimized.In this paper an evolutionary genetic method,non-dominated sorting genetic algorithmⅡ,is applied to optimize the injector beam dynamics,especially in the highcharge operation mode.Study shows that using an incident laser with rms transverse size of 1-1.2 mm,the normalized emittance of the electron beam can be kept below 1 mm·mrad at the end of the injector.This work,together with the previous optimization of the low-charge operation mode by using the iterative scan method,provides guidance and confidence for future construction and commissioning of the ERL-TF injector.展开更多
A proposed compact ERL test facility at IHEP, Beijing, is presented in this paper, and includes the design parameters, the essential lattice, and the key components features, such as the photocathode DC gun and the CW...A proposed compact ERL test facility at IHEP, Beijing, is presented in this paper, and includes the design parameters, the essential lattice, and the key components features, such as the photocathode DC gun and the CW superconducting accelerating structures. Some important beam physics issues such as the space charge effect, the coherent synchrotron radiation (CSR) effect and the beam break-up (BBU) effect are briefly described with the simulation results.展开更多
The maximum beam current that can be accelerated in an energy recovery linac(ERL) can be severely limited by the transverse multi-pass beam breakup instability(BBU),especially in future ERL light sources with multi-Ge...The maximum beam current that can be accelerated in an energy recovery linac(ERL) can be severely limited by the transverse multi-pass beam breakup instability(BBU),especially in future ERL light sources with multi-Ge V high energy beam energy and more than 100 m A average current. In this paper,the multi-pass BBU of such a high energy ERL is studied based on the simulation of a 3-Ge V ERL light source that is proposed by KEK.This work is expected to provide a reference for future high energy ERL projects.展开更多
文摘中国科学院高能物理研究所提出了ERL-FEL(Energy recovery linac-Free electron laser)"一机两用"的概念,通过同一直线加速器将能量回收加速器(Energy recovery linac,ERL)和自由电子激光(Free electron laser,FEL)结合到一起。本文讨论ERL-FEL两用实验装置主体屏蔽设计中,利用离散抽样的方法实现多个损失源项的整合,在同一FLUKA用户程序中实现多源抽样,并将蒙特卡罗计算结果与各源项独立处理的累积结果进行对比。计算表明,两者的结果吻合较好。基于束流损失源项整体建模的方法适用于其他小型直线加速器的整体屏蔽计算,可方便在其他装置上扩展应用。
文摘The energy recovery linac test facility(ERL-TF), which is a compact ERL-FEL(free electron laser)two-purpose machine, was proposed at the Institute of High Energy Physics, Beijing. As one important component of the ERL-TF, the photo-injector that started with a photocathode direct-current gun has been designed. In this paper, optimization of the injector beam dynamics in low-charge operation mode is performed with iterative scans using Impact-T. In addition, the dependencies between the optimized beam quality and the initial offset at cathode and element parameters are investigated. The tolerance of alignment and rotation errors is also analyzed.
基金Supported by Major State Basic Research Development Program of China (2011CB808303, 2011CB808304)
文摘Generally, the Energy Recovery Linac (ERL) needs specially designed high current superconducting RF cavities. In this paper, the threshold current of beam breakup for compact ERL facilities with 9-cell Tesla type cavities are investigated. The results show that it is feasible to adopt the 9-cell Tesla cavity for compact ERL test facilities with just a few cavities and beam current around 10 mA.
文摘Both the energy recovery linac (ERL) and the free electron laser (FEL) are considered to be candidate fourth generation light sources. It is proposed to combine an FEL into an ERL facility to integrate the advantages of both, and to realize a compact two-purpose light source. A test facility to verify this principle is being designed at the Institute of High Energy Physics, Beijing. One main concern is the beam breakup (BBU) instability which limits the available beam current. To this end, we developed a numerical simulation code to calculate the BBU threshold, which is found to have only a small reduction even in a high-FEL-bunch-charge operation mode, compared with that in the case with ERL bunches only. However, even with the ERL beam current far below the BBU threshold, we observed a fluctuation of the central orbit of the ERL bunches in the presence of an FEL beam. We then present a physical model of BBU and understand the mechanism of the orbit-fluctuation in an ERL-FEL two-purpose machine. We found that by choosing an appropriate FEL bunch repetition rate, the central orbit fluctuation amplitude can be well controlled.
文摘The energy recovery linac test facility(ERL-TF),a compact ERL-FEL(free electron laser)two-purpose machine,has been proposed at the Institute of High Energy Physics,Beijing.As one important component of the ERL-TF,the photo-injector was designed and preliminarily optimized.In this paper an evolutionary genetic method,non-dominated sorting genetic algorithmⅡ,is applied to optimize the injector beam dynamics,especially in the highcharge operation mode.Study shows that using an incident laser with rms transverse size of 1-1.2 mm,the normalized emittance of the electron beam can be kept below 1 mm·mrad at the end of the injector.This work,together with the previous optimization of the low-charge operation mode by using the iterative scan method,provides guidance and confidence for future construction and commissioning of the ERL-TF injector.
文摘A proposed compact ERL test facility at IHEP, Beijing, is presented in this paper, and includes the design parameters, the essential lattice, and the key components features, such as the photocathode DC gun and the CW superconducting accelerating structures. Some important beam physics issues such as the space charge effect, the coherent synchrotron radiation (CSR) effect and the beam break-up (BBU) effect are briefly described with the simulation results.
基金Supported by Major State Basic Research Development Program of China(2011CB808404)
文摘The maximum beam current that can be accelerated in an energy recovery linac(ERL) can be severely limited by the transverse multi-pass beam breakup instability(BBU),especially in future ERL light sources with multi-Ge V high energy beam energy and more than 100 m A average current. In this paper,the multi-pass BBU of such a high energy ERL is studied based on the simulation of a 3-Ge V ERL light source that is proposed by KEK.This work is expected to provide a reference for future high energy ERL projects.
