超短パルスレーザー駆動X線管を用いた時間分解蛍光X線分光システムの開発

抄録

A femtosecond-laser-driven X-ray source and an X-ray focusing system have been developed for the time-resolved X-ray fluorescence spectroscopy. The X-ray source, in which a plasma cathode induced by a 10¹³-W/cm² laser pulse serves as an electron source of an X-ray tube, provides 10⁹ Cu K_α photons in 4πsr per pulse. The X-ray pulse duration is measured to be about two hundred nanoseconds. Emission analysis of the plasma cathode indicates that the temporal characteristics of the X-ray pulse are determined by the dynamics of the plasma particles under the electrostatic shielding against the applied voltage in the X-ray tube. As for the X-ray focusing system, a focal spot size by a polycapillary lens is measured and the enhancement of X-ray fluorescence intensity due to the lens is demonstrated.