A high‐duty‐cycle long‐pulse electron gun for electron accelerators

We describe the design and operation of a long‐pulse (200–300 μs), high‐duty‐cycle (5%–6%), 8‐mm‐diam dispenser cathode, electrically isolated, modulating Wehnelt electron gun for applications in a high‐average‐power electron linear accelerator. The electron optics design was optimized with computer modeling of the electron trajectories and equipotentials. The gun performance was established in a series of experimental measurements in a test stand. Excellent pulse‐to‐pulse emission current reproducibility and electron‐beam pulse profile stability were obtained.