Generation of iodine L-shell X-rays under excitation of large CF3I clusters by femtosecond laser radiation

The use of clusters of polyatomic molecules with a relatively low ionisation energy (~10 eV) is proposed for the efficient production of X-ray radiation. We have observed for the first time the generation of characteristic X-ray radiation due to L transitions in iodine atoms under the high-intensity femtosecond laser irradiation of molecular CF₃I clusters, which were a small admixture to Ar carrier gas. The X-ray conversion efficiency amounts to ~10^-6 (for a yield of ~10⁷ photons per pulse), which is an order of magnitude higher than the efficiency we obtained in the case of argon clusters under comparable conditions.