Generation of High-Current-Density Sheet Electron Beams

High-current-density sheet beams directly generated from scandia-doped dispenser cathodes have been studied for application to vacuum electron devices like terahertz sources. Rectangular beams with current densities of over 50 $\hbox{A/cm}^{2}$ have been developed and demonstrated to maintain for several hundred hours with the cathode operating stably at 950 $^{ \circ}\hbox{C}_{b}$. Beam forming structures have been investigated and optimized by means of beam profile simulation and confirmed by test results.