A shadow-grid modulated electrostatically focused klystron

Electrostatically focused klystrons have been improved by the incorporation of a shadow-grid controlled electron gun. The shadow-grid gun permits high modulation rates and complex modulation waveforms to be applied to the klystron with low voltage, low power modulation circuits. Although shadow-grid guns have been employed in magnetically focused linear beam tubes for several years, this is the first reported application in an electrostatically focused klystron. The effect of an electrostatic focusing lens system on an electron beam generated by a shadow-grid electron gun was not known and required study by digital computer techniques. Many questions concerning electron beam stability at all values of grid voltage had to be answered prior to incorporating a shadow-grid gun into an ESFK. Computer studies of a 0.7 microperveance electron beam indicated stable focusing for all values of control grid voltage.