Measurements of improved cathode performance using a ceramic honeycomb secondary emitter

Experiments carried out on the electra laser main amplifier (500 kV, 100 kA, 100 ns, 5 Hz) show that inserting a slab of ceramic honeycomb in front of a large area cathode (2600 cm/sup 2/) improves the electron beam emission uniformity, decreases the beam current rise and fall times, and maintains a more constant diode impedance. A more robust cathode that starts to emit at a higher electric field without degradation in uniformity is achieved by using carbon fiber as the primary emitter. These qualities, the simplicity of design, and the low cost make the ceramic honeycomb cathode an interesting candidate for long lifetime use in the krypton-fluoride lasers proposed for inertial fusion energy.