New developments in electrostatically focused klystrons

Significant advances have recently been made in the state of the art of electrostatically focused klystrons (ESFK´s). Digital computer design of the electrostatic focusing lens system has increased the electron beam transmission, with saturated rf drive, from approximately 70 to 93 percent. Higher gain-bandwidth products have been achieved with a five cavity, interaction circuit designed by a digital computer program which includes the effect of the dc lens fields on the rf bunching of the electron beam. Experimental verification has been made of the low noise performance of ESFK´s and the absence of coherent ion noise which results from positive ion drainage by the focusing lenses.