Development of a Smith-Purcell Free Electron Laser Driven by the NCCU Microwave Gun

Abstract

Abstract : The intent of this project was to study the operation of a Smith-Purcell FEL (SP-FEL) when driven by the short, high-power, relativistic electron micropulses produced by the NCCU Electron Gun. The motivation was the development of an SP-FEL that would bridge the wavelength range from the sub-mm up to the infrared, a wavelength range for which an easily tunable, coherent source would be a major advance. During the period of this project, the electron gun, the interaction chamber, gratings, and the diagnostic systems were developed to conduct the proposed study. The spontaneous radiation generated when the electron beam passed over a grating was studied. The initial conclusion is that Smith-Purcell radiation from the grating was mixed with a significant amount of transition radiation, produced when portions of the relativistic electron beam strike the body of the grating. The strength of the Smith-Purcell radiation compared to the transition radiation suggests that, at least for the experimental conditions used in this experiment, the coupling of the electron beam to the grating was inefficient.