Simulation and experiment on Cusp gun for second harmonic Gyro-TWT
The Cusp electron gun for second harmonic Gyro-TWT is simulated by the three dimensional PIC software and Ukrainion electronic optical software TAU,and the electronic 3D velocity value is extracted to calculate the velocity ratio of the transverse velocity and longitudinal velocity.With the anode voltage and the cathode current changing,the variational process of the electron velocity ratio and spread is simulated,and the results of the average velocity ratio 1.1 and spread 9.5% are obtained.Based on the mean radius of the electron beam and the relationship between the radius and the transverse,longitudinal relocity,an experimental method of measuring the electron velocity ratio is put forward.When the electron holding some energy shock at a fluorescence glass,the light spot induced in the fluorescence glass is caught by a camera,then the mean radius of the light spot is measured by some graphics soft.On the basis of the mean radius of the light spot,the electron velocity ratio is calculated.The error is about 15% compared with the simulation result.