Efficient generation of Xe K-shell x rays by high-contrast interaction with submicrometer clusters

The interaction between a 25 TW laser and Xe clusters at a peak intensity of 1 × 10¹⁹ W/cm² has been investigated. Xe K-shell x rays, whose energies are approximately 30 keV, were clearly observed with a hard x-ray CCD at 3.4 MPa. Moreover, we studied the yield of the Xe K-shell x rays by changing the pulse duration of the laser at a constant laser energy and found that the pulse duration of 40 fs is better than that of 300 fs for generating Xe K-shell x rays.