Spectral shape of K X-rays produced by ultra short pulse laser

When a strong laser beam hits the surface of a material, plasma is produced there, subsequently leading to the emission of a short burst of X-rays. It is believed that the electrons in the surface plasma are accelerated by the strong electric field of the laser and then penetrate the solid behind. There, they knock out electrons from inner electronic shells, which subsequently undergo inner-shell recombination, leading to characteristic line emissions such as Kα and Kβ spectra. A research group led by Professor U. Teubner (University of Applied Sciences, Emden, Germany) has reported detailed experimental results on copper and titanium K X-rays. Particular attention has been paid to the interplay between the angle of incidence of the laser beam on the target, as well as the influence of prepulses. For more information, see the paper, "Optimized K x-ray flashes from femtosecond-laser-irradiated foils", W. Lu et al., Phys. Rev. E 80, 026404 (2009).