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
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 advanta...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
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.
