中央研究院 原子與分子科學研究所

A tomographic diagnosis method was developed to systematically resolve the injection and acceleration processes of a monoenergetic electron beam in a laser wakefield accelerator. It was found that all the monoenergetic electrons are injected at the same location in the plasma column and accelerated from 5 MeV to 55 MeV energy in 200-μm distance. This is a direct measurement of the real acceleration gradient in a laser wakefield accelerator, and the experimental data are consistent with the model of transverse wave-breaking and beam loading for monoenergetic electron injection.