Recently, a very stimulating paper has been published discussing experimentally the fundamental processes of photo-absorption and excitation of electrons by using extremely high-fluence, ultra-short X-ray pulses.  The research was done for the electron system in inert Ne gas at LCLS (Linac Coherent Light Source), Stanford, USA, which is the world's first hard X-ray free-electron laser facility.  The scheme is as follows: an intense single X-ray pulse of sub-10-fs duration at 848 eV first strips a 2p electron from Ne and, at this stage, since the X-ray energy is below the binding energy of a 1s electron in neutral neon, 870 eV, a 1s hole cannot be produced, but because of the above 2p hole, the next pulse can excite the 1s electron, leading to 1s-2p resonance in the Ne⁺ ion and, finally, stimulated emission (2p-1s) competes with Auger decay to refill the 1s hole.  The results have indicated that intense X-ray pulses of sub-10-fs duration can modify and even control the Auger decay process.  For more information, see the paper, "Unveiling and Driving Hidden Resonances with High-Fluence, High-Intensity X-Ray Pulses", E. P. Kanter et al., Phys. Rev. Lett. 107, 233001 (2011).

BaTiO₃ is a promising candidate ferroelectric material for magnetoelectric composites and layered film structures.  Recently, some interesting soft X-ray absorption spectra at Ti-L_{II, III} , O-K, and Ba-M_{IV, V} edges have been discussed mainly from a theoretical point of view by a German group.  For more information, see the paper, "High-resolution x-ray absorption spectroscopy of BaTiO₃: Experiment and first-principles calculations", A. Chassֺé et al., Phys. Rev. B84, 195135 (2011).

Multi-wavelength anomalous diffraction (MAD) has been widely employed to determine phase information in X-ray crystallography.  The method uses the contrast of the scattering power of heavy atoms at the absorption edges.  However, when the X-ray source becomes extremely brilliant, the sample encounters severe electronic radiation damage, especially to heavy atoms, which makes the interpretation of MAD rather difficult.  Recently, a theoretical paper discussing this problem has been published.  The theory uses a Karle-Hendrickson-type equation in the high-intensity regime, and demonstrates the calculation of relevant coefficients with detailed electronic damage dynamics of heavy atoms.  For more information, see the paper, "Multiwavelength Anomalous Diffraction at High X-Ray Intensity", S-K.Son et al., Phys. Rev. Lett. 107, 218102 (2011).

The recipient of the 6th Asada Award, which is presented by the Discussion Group of X-ray Analysis, Japan, in memory of the late Professor Ei-ichi Asada (1924-2005) to promising young scientists in X-ray analysis fields in Japan, is Dr. Takashi Yamamoto (Tokushima Univ., "Studies on pre-edge peak in XANES spectra of transition metals for empirical chemical state analysis").  The ceremony was held during the 47th Annual Conference on X-Ray Chemical Analysis, Japan, at Kyushu University, Fukuoka.

Empirical and semiempirical K-shell fluorescence yields (ωK) and Kβ/Kα intensity ratios for ZnCo alloy with various chemical compositions, leading to differences in pH, have recently been published.  The samples were excited by 59.5-keV γ rays from a ²⁴¹Am annular radioactive source, and X ray fluorescence spectra were measured by an Ultra-LEGe detector.  For more information, see the paper, "Effect of pH treatment on K-shell x-ray intensity ratios and K-shell x-ray-production cross sections in ZnCo alloys", N. Kup Aylikci et al., Phys. Rev. A84, 042509 (2011).

A Korean group led by Professor J. H. Je (Pohang University of Science and Technology) has recently reported some interesting experiments on water vaporization by X-ray photons.  The experiments were done at the undulator beamline, XSD 32-ID, Advanced Photon Source in Argonne, USA.  It was found that water is vaporized at a rate of 5.5 pL/sec at a 100 msec exposure of 1-Å-wavelength (~13 keV) X-ray irradiation of around 10⁷ photons/μm² (0.1 photons/Ų), which corresponds to a dose rate of ~50 kGy/sec.  They also confirmed that water vapor is reversibly condensed during pauses in irradiation.  This result suggests that photoionization induces vaporization through the reduction of the surface tension of water.  For more information, see the paper, "X-ray-induced water vaporization", B. M. Weon et al., Phys. Rev. E84, 032601 (2011).