The relation between X-ray intensity and ion energy of laser triggered ion acceleration

When an ultrashort and intense laser pulse is irradiated onto a target, generation of energetic ions and energetic X-ray has strong relations because electrons generate both ions and X-rays. In this work, we measured the relation between X-ray intensity and the ion energy. The temperature of X-ray was measure to be 300-350 keV when the laser intensity was 3.3$\,\times\,$1018W/cm2. The maximum proton energy was 1.65$\,\pm\,$0.25 MeV for the laser energy of 200 mJ at the optimum target position where X-ray intensity was maximum.