L-shell X-ray conversion yields for laser-irradiated tin and silver foils

Abstract

We have employed the VULCAN laser facility to generate a laser plasma X-ray source for use in photoionisation experiments. A nanosecond laser pulse with an intensity of order ${10}^{15}$ W{cm}$^{-2}$ was used to irradiate thin Ag or Sn foil targets coated onto a parylene substrate, and the L-shell emission in the $3.3-4.4$ keV range was recorded for both the laser-irradiated and non-irradiated sides. Both the experimental and simulation results show higher laser to X-ray conversion yields for Ag compared with Sn, with our simulations indicating yields approximately a factor of two higher than found in the experiments. Although detailed angular data were not available experimentally, the simulations indicate that the emission is quite isotropic on the laser-irradiated side, but shows close to a cosine variation on the non-irradiated side of the target as seen experimentally in previous work.