Sheet electron beam gun design using Argus

An electron gun that will produce dual sheet electron beams for use in a 1-MW, 120-GHz quasioptical gyrotron has been designed. This sheet beam, due to its inherent 3-D geometry, must be simulated with a 3-D code. Using the 3-D PIC (particle-in-cell) code Argus in the electrostatic relaxation mode, equilibrium electron ray traces and fields are presented. Although the study is not complete, the simulation results obtained thus far reveal many of the physics issues associated with the device. In particular, the consequences of the E×B drift of the particles as it concerns the issues of segmenting the sheet beam into beamlets for optimization are studied. At this stage in the study, it appears that beam segmentation is very promising, since beamlet resolution was quite good after compression. Also, the choice of cathode skew angle was quite good