Simulations of hard X-ray generation by hot electrons in a silver target

摘要

A semi-analytical model is developed for the generation of X-ray bremsstrahlung in metallic targets with the inclusion of hot electron recirculation (refluxing). The hard bremsstrahlung and characteristic X-ray yields are calculated in relation to the thickness of a silver target for an s-polarised subpicosecond laser pulse intensity of 2 x 10(19) W cm(-2). The effect of hot electron recirculation in thin foils is shown to significantly improve the K-alpha radiation and bremsstrahlung yields in a photon energy of 10-100 keV. By contrast, the 0.1-1 MeV bremsstrahlung photon yield from thin foils with hot electron recirculation corresponds approximately to the highest photon yield from those targets in which recirculation is insignificant. We make a comparative analysis of the highest laser-to-X-ray energy conversion efficiencies obtained to date.