A High Frequency Hybrid Photoinjector

70853 This project will develop a compact, inexpensive high-brightness electron source, which is a variation on the ratio-frequency photoinjector. By making the photoinjector out of a hybrid standing-wave-gun section that is electromagnetically coupled to a downstream traveling wave section, the radio-frequency power system for energizing an accelerator can be simplified, allowing the development of unprecedented high-brightness electron sources. In Phase I, a preliminary study of the issues needed to design an optimized, high brightness, standing wave/traveling wave hybrid radio-frequency photoinjector will be conducted. Issues of electromagnetic design will be addressed, with particular emphasis on the near elimination of reflected waves from the device, as well as on maximizing energy and efficiency. In addition, related issues of beam dynamics optimization for lowest emittance and highest brightness performance will be addressed. A method for integrating these systems into a high brightness photoinjector design will be developed. Commercial Applications and Other Benefits as described by the awardee: A commercially available high brightness, high energy electron source would be of interest to university, national, and industrial research labs for high energy physics, advanced accelerators, and radiation production devices such as the free-electron laser. It also could enhance the performance of present day medical accelerators and allow the development of new medical techniques based on nearly monochromatic x-rays produced by Thomson scattering of laser pulses from the electron beam.