Observation of screening effect in large-area, cold-cathode diodes

Abstract
In this work we report the first observation of the screening effect in large‐area, cold‐cathode diodes. A framing camera was used to observe the formation of emission centers (ECs) on a 200 cm2 velvet emitter. The density of ECs increased as a function of applied magnetic field as predicted. The current per EC decreased as the magnetic field was increased. These phenomena suggest methods of increasing the spatial and temporal uniformity of high‐power electron beams.