Design and testing of an electron gun producing a segmented sheet beam for a quasi-optical gyrotron
A high-power sheet beam electron gun for a quasi-optical gyrotron has been developed. The gun produces two beams with rectangular cross sections, with one beam segmented into 11 beamlets. The beamlets are spaced so as to be in line with the maxima of the RF field profile in the resonator of a 120-GHz quasi-optical gyrotron. The maximum current in the segmented beam is nominally 34 A, while the unsegmented beam is 68 A. The gun has been tested, and it has operated essentially as predicted by 2-D and 3-D theory. In particular, the overall beam shape is largely undistorted, and the beamlets are, for most cases, well aligned. >