We present measurement of characteristic KαKα emission from Mo, Ag, and La targets irradiated by a 60 fs, 600 mJ, 10 Hz Ti:sapphire laser pulse at 1017–1019 W/cm2.1017–1019W/cm2. These x-ray emissions can potentially be used in applications from laser-based hard x-ray sources to x-ray mammography so detailed knowledge of the spectra is required to assess imaging of the figure of merit. We show here that high resolving hard x-ray spectroscopy can be achieved, with resolving powers (E/ΔE)(E/ΔE) of 60 at 18 keV, with cadmium–zinc–telluride detection system. The KαKα conversion efficiency from the laser light to the KαKα photon was optimized thanks to this diagnostic and values as high as 2×10−52×10−5 were obtained. © 2003 American Institute of Physics.