电子束收集极对大间隙速调管输出腔效率的影响

Influence of electron beam collector on output cavity efficiency of wide-gap klystron amplifier

利用高频电磁软件对带电子束收集极的S波段大间隙输出腔进行了高频特性分析,采用3维PIC程序模拟了电子束收集极对大间隙速调管输出效率的影响。研究结果表明:收集极的存在会改变输出腔的本征谐振频率和电子束路径上的特性阻抗等高频特性,但收集极可以短路间隙附近的径向电场,减小电子束的空间电荷压力,同时对群聚电子进行再加速,从而提高大间隙速调管的输出效率;在束电压700kV,直流电流6kA时,优化后的带收集极的大间隙输出腔可稳定提取大于1.68GW的微波功率,提取效率约40.1%,比无收集极时提高约5%。

High frequency characteristics analysis and three-dimension fully electromagnetic particle-in-cell（PIC） simulation about the electron beam collector influence on the wide gap klystron（WKA） output power efficiency was presented.The electron beam collector will change the high frequency characteristics of the WKA output cavity.However,the collector nearby the output cavity gap will short out the radial electric field and reduce the space-charge potential depression,which as a result increase the WKA output power efficiency.By using a three-dimension fully electromagnetic PIC code,the output cavity power extraction effect was simulated.At beam voltage of 700 kV,cathode current of 6 kA and current modulation depth of 94%,the WKA with an optimized beam collector outputs microwave power of 1.68 GW at 3.62 GHz,with a power efficiency of about 40.1% which is 5% higher than without collector.