Investigation for FEL spectrum narrowing

采用分布反馈系统将强流电子束注入摇摆器。观察到自由电子激光振荡现象。获得了窄化的诱导发射。实验结果如下：1）在1 mm波长处获得了600 kW的超辐射，谱宽为<plus-minus>20%; 2）采用分布反馈，谱宽为<plus-minus>5%，理论上解释了实验结果; 3）获得了30 db/1.8m的增益，现将实验结果进行总结并发表。正在规划高梯度加速等应用实验.

High current electron beam was injected into a wiggler with distributed feed back system. FEL oscillation was observed. Narrowing of induced emission was obtained. The results are as follows.1) We obtained a superadiance of 600kW in 1mm wavelength the spectrum width was <plus-minus>20% in this cas2) Using the distributed feed back, the spectrum width was <plus-minus>5% and the results of experiment, were explained by the theor3) The gain we obtained was 30db/1.8m.We are summarizing the results to publish. Application experiments are planning such as high gradient acceleration.