Electron Gun Shielded Aperture Structure for Secondary Electron Suppression

The extraction electrode is divided into multiple functional zones: a first diaphragm for limiting primary electron beam passage, a second diaphragm for limiting secondary electron passage, and intermediate electrodes positioned between them. This segmentation allows each component to address specific electron control functions, effectively preventing secondary electron mixing while maintaining structural organization.

Intermediate electrodes are introduced between the first and second diaphragms to create additional electric field zones. These intermediary elements modify the electric field distribution to prevent secondary electrons generated at the diaphragms from reaching the primary beam path, thereby eliminating flare without requiring a single complex barrier.

The intermediate electrodes serve multiple functions: they create electric field barriers to block secondary electrons, maintain potential gradients for primary electron acceleration, and work cooperatively with both diaphragms. This multi-functionality reduces the need for separate dedicated components, thereby limiting complexity growth while achieving effective flare suppression.

The electron gun structure is organized in nested layers: the first diaphragm is positioned within the extraction electrode, the intermediate electrodes are positioned between the diaphragms, and the second diaphragm is positioned downstream. This nested arrangement allows compact integration of multiple functional elements without excessive spatial occupation, managing device complexity through efficient spatial organization.