Microwave Thermionic Electron Gun for Synchrotron Light Sources

Conventional thermionic RF guns can offer high average beam current, which is important for synchrotron light and THz radiation sources facilities, as well as for industrial accelerators. However, the thermionic RF guns are based on a decades old design, suffer from mechanical and thermal problems, and are generally due for a major upgrade and replacement. In response to this problem, RadiaBeam Systems proposes to design and build a new, more stable and reliable gun with optimized electromagnetic performance, improved thermal engineering and more robust cathode mounting technique. These tasks will be performed with cutting edge numerical modeling, multi-physics and beam dynamics simulation tools, and also using a proven design methodology developed by the company. This project is proposed as a Fast Track, since there is an immediate need to upgrade the thermionic injector at the Advanced Photon Source, where RadiaBeam and Argonne have jointly developed a tunable THz source. In the Phase I we will develop a prototype RF gun cavity with the improved RF contacts and exchangeable cathode back-plate, build the dummy cavity and RF stand to test the performance of the back-plate, frequency sensitivity, and tuning capability, using the available high power sources. In Phase II, a prototype thermionic RF injector will be fully engineered, fabricated, tested and integrated into the RadiaBeam/APS Terahertz radiation source. Synchrotron light facilities are critical part of the high impact scientific research infrastructure in the US. This project will provide a major upgrade for RF guns, which are used to drive this facilities, as well as emerging compact THz sources. Commercial Applications and Other Benefits: The goal of this project is to build an instrument that will be immediately used by Argonne National Laboratory in their work on improving stable and reliable operation of the Advanced Photon Source. This project also has an immediate impact on an existing joint APS-RadiaBeam THz radiator program, allowing increasing its power and frequency. In addition, a number of the light source facilities worldwide would be interested in replacing their thermionic RF injectors with an updated and improved version.