Brightness and duration of x-ray line sources irradiated with intense 0.53-μm laser light at 60 and 120 ps pulse width

Abstract

Short, bright pulses of x-ray line emission are needed for flash radiography of laser-fusion targets. The experiments described here were carried out with the nominal laser pulse lengths of 60 and 120 ps. The M→L spectra were for Y (2.00–2.35 keV), Pd (2.95–3.46 keV), and Cs (4.43–5.15 keV), and the L→K spectra were for Cl (2.790 keV), Ti (4.749 keV), Mn (6.180 keV), and Ni (7.804 keV). The L→K energies are for the 1s2p thinsp${;}^1$ $P_1$→1$s^2$ ${}^1$ $S_0$ transition. Both the duration and the absolute brightness of the x-ray line emission were measured. Even at 60 ps, the x-ray flashes from Y, Pd, and Ti were all bright and of duration comparable to or shorter than the laser pulse length. In particular, the Pd M→L lines were as bright as 2×${10}^{12}$ photons/j? and the Ti L→K lines as bright as 5×${10}^{10}$ photons/j?.