Experiments were performed with a 15 J/500 ps Nd:glass laser ($\lambda = 1064$ nm) focussed to an intensity > 10¹⁴ W/cm² . X-ray emissions from carbon foam and 5% Pt-doped carbon foam of density 150–300 mg/cc were compared with that of the solid carbon targets. The thickness of the carbon foam was 15 𝜇m on a graphite substrate. X-ray emission was measured using semiconductor X-ray diodes covered with various filters having transmissions in different X-ray spectral ranges. It covered X-ray spectrum of 0.8–8.5 keV range. The X-ray emission in the soft X-ray region was observed to increase to about 1.8 times and 2.3 times in carbon foam and Pt-doped foam, respectively with respect to solid carbon. In hard X-rays, there was no measurable difference amongst the carbon foam, Pt-doped carbon foam and solid carbon. Scanning electron microscope (SEM) analysis demonstrates that foam targets smoothens the crater formed by the laser irradiation.

Monochromatic X-ray backlighting has been employed with great success in various laser plasma experiments including inertial confinement fusion (ICF) research. However, implementation of a monochromatic backlighting system typically requires extremely high quality spherically bent crystals which are difficult to manufacture and are also expensive. In this paper, we present a quasimonochromatic X-ray backlighting system using flat thallium acid pthalate (TAP) crystal. The detailed characterization of the system is discussed. The X-ray backlighter spectral range is caliberated using Cu spectrum in the spectral range 7–9 Å (1.38–1.77 keV). Gold plasma produces continuous X-ray spectrum (M band) in this range. The spectral, spatial and temporal resolutions of the system measured are 30 mÅ, 50 $\mu$m and 1.5 ns respectively. The spectral width of the X-ray pulse is 2 Å ($\Delta E$ = 0.39 keV).