A new FEL concept driven by a vacuum microfielf emitter

Abstract

In order to reduce the scale and construction cost of free election lasers, it is necessary to investigate various new ideas with respect to electron beam generation, acceleration and radiation mechanism. In this paper, a microscale free electron laser is proposed which is driven by a very small diameter (less than a few μm) electron beam. The microscopic electron beam can be generated with a needle cathode, for an example, a Spindt cathode. By injecting the microscopic electron beam into a microdielectric channel, we generate radiations of several μm wavelength by Cherenkov emission, Smith-Purcell emission and so on. In the design of a microfield emitter FEL (MFE FEL). It is shown that a 2 mm long dielectric pipe with an electron beam of diameter 1 μm and with a current of 50 μA gives a one pass gain of 50% for a 10 μm wavelength radiation.