A high-duty Ka-band extended interaction klystron

A high-duty extended-interaction klystron (EIK) is built to power a high-Q cavity for materials processing. The EIK is comprised of a single-gap input cavity, 5 buncher cavities, and a 2-gap output cavity. The cavities can be stagger tuned for broad bandwidth. The gaps are made of CuNi alloy to increase the cavity loading for further bandwidth improvement. A compact neodymium-iron-boron permanent magnet system is employed for electron beam focusing. A depressed collector is employed for overall efficiency enhancement.