High Current Density Carbon Nanotube Cold Cathode for TWT Applications

Traveling wave tubes (TWTs) are key components for generating high frequencies and high power for communication, radar and electronic warfare. Almost all TWTs used to date in active service use thermal cathodes as the electron source needed to generate the high current density beam required for TWT operation. The heat generated by the cathode is difficult to dissipate in space and significantly lowers the efficiency of the TWT device. We propose to demonstrate the feasibility of a carbon nanotube-based electron gun for TWT applications by installing such an electron source in an existing TWT made commercially. A cold cathode approach will improve the efficiency of the TWT and may improve the operating life of the cathode. Payload weight may be lowered since high current, high voltage transformers will not be needed. In Phase I, we showed that high current densities in the range needed for TWT applications, can be obtained from carbon nanotube (CNT) cathodes in both pulsed and DC modes. In this Phase II effort, we will demonstrate the capabilities of CNT electron sources by installing them in existing TWTs made commercially by Northrop Grumman Corp., who will be teaming with ANI to achieve this demonstration.