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We report ultrashort pulse, 1 kHz repetition rate x-ray generation in the 5–20 keV spectral region, induced by the interaction of laser radiation with copper nitrate solution and ethylene glycol liquid-jet targets. The characteristics of the copper nitrate source are relevant for application to time-resolved x-ray diffraction studies as well as for spectroscopic x-ray absorption studies. The x-ray sources were operated uninterrupted for in excess of 5 h with no detectable buildup of debris on the associated optics. The x-ray flux generated by both sources is estimated to be of the order of 106 photons s−1 sr−1 in the 5–20 keV region. The spectra have been measured with both a PIN photodiode, and with transmission measurements taken using aluminum filters. We find that the plasma emission has a broadband component attributed to bremsstrahlung emission, with the bulk of the x-ray emission emitted from the chamber lying between 5 and 20 keV for both sources. The copper nitrate emission, however, delivers a dominant emission peak at 9 keV, attributed to the characteristic K emission of copper.

An extensive structural analysis of a decagonal A163Cu» 5Co» 5Si& alloy is reported. The structure is analyzed within the context of both microcrystalline and quasicrystalline models through the examination of single-crystal x-ray diffraction patterns. We conclude that our sample is in a microcrystalline state formed of coherent twins of an approximant state of the quasicrystal. We underline that diffraction patterns exhibiting sharp peaks and perfect tenfold symmetry do not necessarily correspond to longrange quasiperiodic order, which could have implications for the physical properties of quasicrystal-like alloys. The present work also gives us the opportunity to point out and discuss some general features: (i) the intensity cutoff problem for quasicrystal structure determinations, (ii) the consequence in structure determination if a sample supposed to be a quasicrystal is in fact a microcrystal, and (iii) the proper determination of basis vectors in decagonal quasicrystals.