Development of High Power Gyrotron with High Performance

本课题的研究目的是实现高性能的大功率回旋管。提高了输出毫米波的模式纯度，提高了振荡的稳定性，提高了废电子束的能量回收等效率，从而实现了高性能。研究准光回旋管的现状和工作原理，对认识准光回旋管的发展水平具有重要意义。采用洛桑的准光回旋管。通过卡普顿窗口的高功率毫米波在带有镀金反射镜的法布里-佩罗谐振器中产生。功率的测量是用辛醇进行的，辛醇具有良好的介电性能，沸点为195度。在二次谐波振荡的测量中，利用固体材料在二次谐波处具有不同吸收系数的Macor，可以将二次谐波与基频振荡分离开来。频率测量是通过外差法进行的谐波混频器，其中本振被扫描以分析频谱。目前，准光回旋管采用边缘耦合谐振腔。对环形开槽联轴器、卡塞格伦联轴器和大量纵向开槽联轴器的输出图进行了实验，结果表明，从联轴器对传输线的角度来看，输出图的畸变是不令人满意的。为了克服这一缺点，采用了曲面镜与光栅相结合的方法。在低功率测试中，辐射方向图良好，高斯光束的优值达到99%。此外，从高性能的角度出发，对新型高效高斯光束模式转换器进行了研究。我们认识到，效率为97%的新转换器是苏联人开发的。

The purpose of this research is to achieve the high-power gyrotron with high performance. High performance is achieved by increment in the mode purity of output millimeter wave, stability of oscillation, and increment in the efficiency such as the energy recovering of the spent electron beam. Investigation of the present status and operation on the quasi-optical gyrotron is important in understanding of the present level. The quasi-optical gyrotron in Lausanne is used for the purpose. The millimeter wave with high power through the Kapton window is generated in the Fabry-Perot resonator with the gold plated mirror. Measurement of power is carried out by using octanol which has good dielectric property with the boiling point of 195 degrees. In the measurement of second harmonic oscillation, it is possible to separate the second harmonics from the fundamental oscillation by using the Macor of solid material which has different absorption coefficient at the second harmonics. Frequency measurement is done by the heterodyne method having the harmonic mixer, where local oscillator is swept to analyze the spectrum. Up to date, the quasi-optical gyrotron has a resonator with edge coupling. Experimental results of output pattern from the annular slotted coupling, cassegrain coupling and a lot of longitudinal slotted coupling shows the distorted pattern unsatisfying from the viewpoint of the coupling to the transmission line. To overcome the disadvantage the combination of the curved mirror and the grating is used. In the low power test, the radiation pattern is good and the figure of merit of gaussian beam is 99%. In addition, from the viewpoint of high performance, investigation of new mode-convertor to gaussian beam with high efficiency is also done. We recognize that the new convertor with the efficiency of 97% is developed by Soviets.