Optimization of Electron Storage Ring for Free Electron Laser

自由电子激光器电子存储环的优化

基本信息

批准号：
10450039
负责人：
HAMA Hiroyuki
金额：
$ 9.41万
依托单位：
Tohoku University (1999-2001)Okazaki National Research Institutes (1998)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

1. The observed longitudinal electron distribution distorted by a potential-well distortion effect that takes account the ring impedance divided into resistive and inductive parts. The first FEL macropulse evolves on a negative momentum compaction ring is predicted to be much higher than that on conventional positive momentum compaction ring by a simulation including the potential-well distortion effect. In addition, the FEL power at a equilibrated state on the negative momentum compaction ring would reach the same level as that on the positive ring, even the microwave instability exists.2. The FEL oscillation becomes to be unstable and the its macropulse structure is being varied when the optical resonator is slightly unstable, which was evidently observed by using a streak camera. In order to secure stable FEL oscillation, the FEL pulse and the electron bunch should be strictly kept at the best synchronism. A feedback system was developed to keep such synchronism by detecting a phase difference of those higher harmonics instead of measuring time deviation. The system worked very well and excellently stable FEL was obtained.3. Because of stable FEL oscillation, the electron bunch lengthening due to the FEL interaction was able to be precisely observed. Although the bunch lengthening was apparently not strongly, taking the potential-well distortion effect into account, the FEL induced energy spread derived by a analysis was found to be very large. However agreement of the measured energy spread with a theoretical prediction was not perfect. Further investigation is required.4. Optimization of the cavity mirrors was also developed. By using suitable materials for the coating, mirros with both very high refrectance and transmittance were realized. As a results, the highest record of extracted FEL power on the storage rings was achieved (>0.5 W), which is now followed by a new two-color experiment to study the mechanism of photo-dissociation of gas molecules.

1。观察到的纵向电子分布因电势孔失真效应而扭曲，该效应考虑了环阻抗分为电阻和电感部件。通过模拟（包括电势孔失真效应），第一个FEL大孔在负动量压实环上演变为在常规正动量压实环上的发展。此外，负动量压实环处于平衡状态下的FEL功率将达到与正环上的水平相同的水平，甚至存在微波不稳定。2。 FEL振荡变得不稳定，并且当光学谐振器略微不稳定时，其大孔结构正在变化，这显然是通过使用条纹摄像头观察到的。为了固定稳定的FEL振荡，应严格将FEL脉冲和电子束保持在最佳的同步状态。通过检测那些较高谐波的相位差而不是测量时间偏差，开发了反馈系统来保持这种同步。该系统的运行良好且获得了出色的稳定FEL。3。由于稳定的FEL振荡，因此可以精确地观察到由于FEL相互作用而引起的电子束延长。尽管显然并不强烈，考虑到势孔失真效应，但发现通过分析得出的FEL诱导的能量扩散非常大。然而，测得的能量传播与理论预测的共识并不完美。需要进一步调查4。还开发了腔镜的优化。通过使用合适的材料进行涂层，可以实现具有很高反射和透射率的镜像。结果，实现了储存环上提取的FEL功率的最高记录（> 0.5 W），然后进行了一项新的两色实验，以研究气体分子光解析的机制。