Measurement of emittance diagram of electron gun asymmetrical beam-forming region

The emittance diagram of an asymmetrical beam-forming region (BFR) with a horizontal slot on
G2
was measured by a shadow method on a newly developed experimental system. This system proved to be sufficiently precise. The measured emittance diagrams show that this slot on
G2
reduces the vertical divergence angle and enlarges the horizontal angle without changing the size of the virtual object. In addition, its effect of improving the corner resolution increases with higher current.