Operation of a Sealed-Tube-Vircator High-Power-Microwave Source

The high-power-microwave (HPM) sources currently under development typically require constant pumping to maintain the high vacuum levels required for operation. This pumping is often done with either a cryo- or turbopumping system, either of which would be difficult to deploy in a compact portable system. A compact sealed-tube virtual cathode oscillator (vircator) source has been developed at Texas Tech University (TTU) that does not require a bulky external vacuum pump for operation. This device has a base vacuum pressure in the low range compared to the majority of laboratory HPM sources having vacuum levels in the - range. The reduced amount of trapped gasses in the sealed-tube ultrahigh-vacuum environment has the potential to greatly impact device performance. The TTU sealed-tube vircator is useful as a testbed for studying HPM source optimization under UHV conditions. Measured operational characteristics of the tube utilizing a carbon fiber cathode and a nickel anode are presented, along with radiated microwave measurements.