SBIR-STTR-Far-Tech-DOE Robust S-Band thermionic RF gun with improved back-bombardment suppression

FAR-TECH, Inc.

10350 Science Center Drive, Ste 150, San Diego, CA, 92121-1136

Name: David Newsham
Title: Dr.
Phone: (858) 455-6655
Email: newsham@far-tech.com

https://www.sbir.gov/sbirsearch/detail/1209409

Thermionic electron sources operating a microwave frequencies with longer lifetimes and increased performance will improve the reliability of synchrotron light sources and a new generation of high power terahertz light sources. Increasing the reliability of the electrons sources will improve the stability of operation for users. The robust thermionic electron source uses a short initial cell, followed by a cavity that is electrically uncoupled from the initial cell. The initial short gap delays the launch phase at which back-bombardment of the electrons onto the cathode will occur. This effectively decreases the beam power that will heat the cathode and increased the possible pulse width. The second cavity is uncoupled to the first cavity and is driven independently to maximize beam capture. In Phase I, the feasibility of producing the novel gun design will be determined through RF and beam dynamics simulation. The effectiveness of the short first cell followed by an independently driven cavity will be verified. The ability to cancel the coupling between the two cells will be confirmed and a design of the whole cavity structure will be developed. The cathode mounting system will be designed. Thermionic electron sources operating at microwave frequencies are current limited by electrons that reflect back from the radio frequency fields and heat the cathode. A novel cavity design is being investigated that will decrease the number of reflected electrons and improve the efficiency of the overall electron source. Commercial Applications and Other Benefits: This cavity will be an improvement over existing thermionic guns, allowing for operation at increased duty factor do to the reduction of the electron back-bombardment on the cathode. It has potential uses in synchrotron light sources and high power terahertz sources.

SBIR-STTR-RadiaBeam Systems-DOE-Microwave Thermionic Electron Gun for Synchrotron Light Sources

RadiaBeam Systems

1713 Stewart Street, Array, Santa Monica, CA, 90404

Name: Sergey Kutsaev
Title: Dr.
Phone: (310) 822-5845
Email: kutsaev@radiabeam.com


https://www.sbir.gov/sbirsearch/detail/1209295

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.