Enhanced K_α output of Ar and Kr using size optimized cluster target irradiated by high-contrast laser pulses

We observed that increasing the clusters size and laser pulse contrast can enhance the X-ray flux emitted by femtosecond-laser-driven-cluster plasma. By focusing a high contrast laser (10^-10) on large argon clusters, high flux K_α-like X-rays (around 2.96 keV) is generated with a total flux of 2.5 × 10¹¹ photons/J in 4π and a conversion efficiency of 1.2 × 10^-4. In the case of large Kr clusters, the best total flux for L-shell X-rays is 5.3 × 10¹¹ photons/J with a conversion efficiency of 1.3 × 10^-4 and, for the K _α X-ray (12.7 keV), it is 8 × 10⁸ photons/J with a conversion efficiency of 1.6 × 10^-6. Using this X-ray source, a single-shot high-performance X-ray imaging is demonstrated.