The low divergent x-ray beam from the third-generation synchrotron radiation source such as SPring-8 enables us to observe refraction of x rays that is in the range of microradians. Under an experimental condition for which ray optics is a good approximation, we found that the refraction produces a high-contrast projection image of a mouse when it was recorded at 6.5 m behind the specimen. Especially, the lung is visualized far better than with the conventional imaging which utilizes absorption of x rays. This is a promising new technique for the diagnosis of diseases in the human lung with a low radiation dose.

No abstract

The state-selective dissociation dynamics for anionic and excited neutral fragments of gaseous SiCl 4 following Cl 2p and Si 2p core-level excitations were characterized by combining measurements of the photoninduced anionic dissociation, x-ray absorption and UV/visible dispersed fluorescence. The transitions of core electrons to high Rydberg states/doubly excited states in the vicinity of both Si 2p and Cl 2p ionization thresholds of gaseous SiCl 4 lead to a remarkably enhanced production of anionic, Si − and Cl − , fragments and excited neutral atomic, Si * , fragments. This enhancement via core-level excitation near the ionization threshold of gaseous SiCl 4 is explained in terms of the contributions from the Auger decay of doubly excited states, shake-modified resonant Auger decay, or/and post-collision interaction. These complementary results provide insight into the state-selective anionic and excited neutral fragmentation of gaseous molecules via core-level excitation.

The visibility of breast cancer was studied by two types of Laue angular filter (LAF) under x-ray dark field imaging. One was designed so that a field size of 90 ×90 mm2 was available by a 2.124-mm-thick LAF with a 35 keV x-ray energy. The second was a thin LAF of 125.6 µm thickness with a view field of 10 ×10 mm2 using a 13.7 keV x-ray. The estimated spatial resolutions for the cases of the 2.124-mm-thick LAF and the 125.6-µm-thick LAF were 139 and 23 µm, respectively. This is in good agreement with our experiment.

No abstract