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We report a recent experiment where the first hard x-ray beam line, X-ray Pump Probe (XPP) instrument using the SLAC National Accelerator Laboratory's Linac Coherent Light Source (LCLS) free electron laser, was used to heat thin foils to high energy densities ~ 107J/cm3. An intense 9 keV, 60 fs (FWHM) duration beam with energy of 2 - 4 mJ at the XPP beam line was focused using beryllium lenses to an irradiance approaching 1016Wcm-2. Targets of 0.5 - 3.5 m thick foils of Ag and Cu were studied using a suite of diagnostics including Fourier Domain Interferometry, energy calorimetry and grating and crystal spectrometers. The experimental details and spectroscopic results from the campaign will be described. Preliminary results indicate that the target is heated relatively uniformly to a temperature lower than 20 eV.

The recent commissioning of a X-ray free-electron laser triggered an extensive research in the area of X-ray ablation of high-Z, high-density materials. Such compounds should be used to shorten an effective attenuation length for obtaining clean ablation imprints required for the focused beam analysis. Compounds of lead (Z=82) represent the materials of first choice. In this contribution, single-shot ablation thresholds are reported for PbWO4and PbI2exposed to ultra-short pulses of extreme ultraviolet radiation and X-rays at FLASH and LCLS facilities, respectively. Interestingly, the threshold reaches only 0.11 mJ/cm2 at 1.55 nm in lead tungstate although a value of 0.4 J/cm2is expected according to the wavelength dependence of an attenuation length and the threshold value determined in the XUV spectral region, i.e., 79 mJ/cm2at a FEL wavelength of 13.5 nm. Mechanisms of ablation processes are discussed to explain this discrepancy. Lead iodide shows at 1.55 nm significantly lower ablation threshold than tungstate although an attenuation length of the radiation is in both materials quite the same. Lower thermal and radiation stability of PbI2is responsible for this finding.