Brightness and duration of x-ray line sources irradiated with intense 0.53-<i>μ</i>m 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\ensuremath{\rightarrow}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\ensuremath{\rightarrow}K spectra were for Cl (2.790 keV), Ti (4.749 keV), Mn (6.180 keV), and Ni (7.804 keV). The L\ensuremath{\rightarrow}K energies are for the 1s2p thinsp${;}^{1}$${P}_{1}$\ensuremath{\rightarrow}1${s}^{2}$ ${}^{1}$${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\ensuremath{\rightarrow}L lines were as bright as 2\ifmmode\times\else\texttimes\fi{}${10}^{12}$ photons/j? and the Ti L\ensuremath{\rightarrow}K lines as bright as 5\ifmmode\times\else\texttimes\fi{}${10}^{10}$ photons/j?.