Study Of The Depressed Collector For Gyro-TWT

As millimeter wave and submillimeter wave sources,gyrotron traveling wave tube(Gyro-TWT)has important applications in millimeter wave communication,plasma heating,millimeter wave radar,directional energy weapons and other military and civil fields.Reducing power consumption,reducing the weight and volume of power supply,and improving the efficiency of the whole gyrotron are the urgent problems to be solved.Nowadays,there are two main ways to improve the efficiency of gyrotron TWT: 1.Optimizing the high frequency structure and improving the efficiency of the whole tube by improving the beam-wave interaction efficiency,but the improvement of the beamwave interaction efficiency is limited by some basic principles,and the interaction efficiency of most gyrotron TWTs is below 40%,so this method has greater limitations;2.The depressed collector is used to collect the electron beam after beam-wave interaction,which can effectively recover the energy carried by electron beam,and the efficiency of the whole tube can be greatly improved.In order to effectively improve the efficiency of gyrotron TWT,a design scheme of depressed collector is proposed in this paper.Combining with theoretical analysis and simulation software,the collection efficiency of the depressed collector is up to 45%.Then the transmission characteristics and heat dissipation analysis are investigated.Finally,the experiment is carried out.Specific research as follows:1.The working principle of depressed collector and the factors that may affect the performance of depressed collector are introduced,such as the initial state of electron beam(electron beam after beam-wave interaction),the electron reflux rate,the shape of external magnetic field,etc.;2.On the basis of balancing electron reflux rate and collection effectivenessm,a scheme for designing the basic parameters of the depressed collector is proposed,and the structure of the single-stage and multi-stage depressed collector is designed with examples,so that the depressed collector can recover as much electronic energy as possible,so that the collection efficiency of the two depressed collectors can reach 54.11% and 59.35% respectively,the whole tube efficiency can be increased to 48.29% and 51.32%,and the electron reflux rate can be controlled within 2%.3.The influence of collector level structure on microwave transmission characteristics is calculated by simulation softwave.The tapered structure is used in transition section to ensure the purity of microwave transmission mode and normal transmission characteristics.Then the thermal analysis of the depressed collector is carried out by simulation software to ensure the good heat dissipation of the structure.4.Finally,the experiment of installing the collector is carried out,and the results are analyzed to find out the problems in the experiment.5.Summarizing the work done and putting forward the prospect for the future.Through theoretical analysis and case design,this paper provides a certain method for the design of depressed collector of gyrotron traveling wave tube.