Photoneutron cross sections were measured for 91Zr, 92Zr, and 94Zr near the neutron separation energy with quasimonochromatic gamma rays. The data exhibit some extra components around the neutron threshold. A coherent analysis of the photoneutron data for 92Zr together with the neutron capture on 91Zr based on the microscopic Hartree-Fock-Bogoliubov plus quasiparticle random-phase approximation model for the E1 strength has revealed the presence of an M1 resonance at 9 MeV. The microscopic approach systematically shows the same M1 strength in the photoneutron cross section for 91Zr and 94Zr. The total M1 strength is about 75% larger than the strength predicted by the systematics, being qualitatively consistent with the giant M1 resonance observed in the inelastic proton scattering.

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A tabletop femtosecond time-resolved soft x-ray transient absorption spectrometer Rev. Sci. Instrum. 79, 073101 (2008);We show experimentally the possibility of nanostructuring (about 20 nm) of gold surface by picosecond soft x-ray single pulse with low fluence of $20 mJ/cm 2 . The nanometer-scale changes of the surface structure are due to the splash of molten gold under fluence gradient of the laser beam. In addition, the ablation process occurs at slightly higher fluence of $50 mJ/cm 2 . The atomistic model of ablation is developed which reveals that the low threshold fluence of this process is due to the build-up of the high electron pressure and the comparatively low electron-ion energy relaxation rate in gold. The calculated ablation depths as a function of the irradiation fluence are in good agreement with the experimental data measured for gold surface modification with ultra-short duration soft x-ray and visible lasers. V C 2012 American Institute of Physics.

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Photoneutron cross sections for (181)Ta(y, n) (180)Ta(m) were determined from simultaneous measurements of total cross sections (sigma(tot) and ground-state cross sections (sigma(gs)) for (180)Ta in photodisintegration of with laser Compton-backscattered rays. Techniques of direct neutron counting and photoactivation were used for the measurement of sigma(tot) and sigma(gs), respectively. The partial cross sections for the isomeric state serves as a novel probe of the nuclear level density of (180)Ta. Implications for the p- and s-process nucleosynthesis of (180)Ta(m) are given.