Dispersive XAFS image radiograph by parametric X-ray radiation

The parametric X-ray (PXR) generator system at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University is a variable-wavelength and quasi-monochromatic X-ray source, which was developed as one of the advance applications of the 125-MeV electron linear accelerator. Since the first observation of the X-rays generated by the system in April 2004, application studies have been performed using the PXR beam in the region from 6.0 to 20keV. The PXR beam extracted from the fixed output port of the generator has characteristic energy dispersion. The theoretical energy spread at the output port with an inner diameter of 98mm changes approximately from 300eV to 2keV depending on central X-ray energy from 7keV and 20keV. The dispersion occurs linearly only in horizontal direction, with a high energy resolution. The characteristics of the PXR beam from the generator suggest a possibility of for the kind of energy dispersive X-ray absorption fine structure (DXAFS) measurement using density distribution in the radiographs of materials. Using the uniform film of the sample materials, DXAFS can be deduced from the measurement of the horizontal density distribution in the radiograph due to the characteristics of the PXR beam. Since the PXR generator system is based on the S-band liner accelerator, it has the potential for the time-resolved XAFS measurement with several ten pico-second resolutions.