High current operation of the crossed-field secondary emission electron source

The crossed-field secondary emission (CFSE) diode is an electron source of a magnetron type that is capable of producing high current tubular electron beams in the range of 10/sup 2/-10/sup 3/ A. The electron beam is generated by means of a self-sustained secondary emission thus making the CFSE diode an essentially cold electron source. This results in a very high temporal stability of the electron beam which has a wall thickness of /spl sim/1 mm. The above features, together with an extremely simple and compact design, make the CFSE electron source attractive in various applications including electron accelerator systems and high power microwave production. This work has been aimed at determining the conditions under which the CFSE electron source produces high electron currents while retaining simultaneously reliable self-excitation. Several methods for achieving that goal have been identified and these have been validated experimentally and analysed in some detail. As a result of this research, stable electron beams with perveance of /spl sim/85 /spl mu/A/V/sup 3/2/ and current /spl sim/240 A were generated.