Direct Imaging with Hundreds of MeV Electron Bunches from Laser Wakefield Acceleration

Direct imaging is a key tool for diagnostics of density transition in different material composition. Ultrafast electron bunches from 100 TW‐level laser system are attractive in future applications. Experiments for direct imaging with 100 MeV electrons are conducted using a 200 TW laser facility in Peking University. Electron bunches with energy spectra ranging from 100 to 150 MeV are achieved with a mixture gas of 0.5% nitrogen and 99.5% helium. Herein, the contrast imaging, transmission, and slit experiments are conducted and analyzed. It turns out the superiority of the hundreds of MeV electrons in thick material imaging applications. It is also anticipated that this technology can be used for ultrafast dynamic analysis with the advent of higher charge electrons in a single ultrafast bunch from laser‐driven electron accelerators.