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势阱畸变效应而畸变，该效应考虑了分为电阻和电感部分的环阻抗。通过包含势阱畸变效应的模拟，预计负动量压缩环上产生的第一个 FEL 宏脉冲将远高于传统正动量压缩环上的演化。此外，即使存在微波不稳定性，负动量压缩环上平衡态的FEL功率也将达到与正环上相同的水平。 2．当光学谐振腔稍微不稳定时，FEL振荡变得不稳定，其宏脉冲结构正在发生变化，这通过使用条纹相机可以明显观察到。为了保证FEL稳定振荡，FEL脉冲和电子束团应严格保持最佳同步。开发了一种反馈系统，通过检测这些高次谐波的相位差而不是测量时间偏差来保持这种同步。系统运行良好，获得了非常稳定的FEL。 3．由于 FEL 振荡稳定，因此能够精确观察到由于 FEL 相互作用而导致的电子束伸长。虽然束团延长显然不强，但考虑到势阱畸变效应，分析得出的FEL感应能量扩散非常大。然而，测量的能量分布与理论预测的一致性并不完美。需要进一步调查。4。还开发了腔镜的优化。通过使用合适的涂层材料，实现了具有非常高的折射率和透射率的镜子。结果，存储环上提取的 FEL 功率达到了最高记录（>0.5 W），随后进行了新的双色实验来研究气体分子光解离的机制。