High energy high resolution monochromatic x-ray computed tomography using the Photon Factory vertical wiggler beamline

Abstract

We have developed a high resolution monochromatic x-ray computed tomography system using synchrotron radiation in the energy range up to 50 keV. The system was installed in a vertical wiggler beamline (BL14C) at the Photon Factory of the National Laboratory for High Energy Physics, and consists of a double-crystal monochromator employing asymmetric Bragg reflections, a photodiode array detector with a phosphor screen, and a microcomputer for control. Computed tomography (CT) images with a pixel size of 6 to 8 μm and with a slice width ranging from 20 to 100 μm were obtained. An image subtraction technique for CT images above and below the x-ray absorption edge of iodine was also evaluated for liquid-containing glass capillaries. Since the CT value (pixel weighting) is linearly proportional to the concentration, the system can quantitatively evaluate the concentration distribution of iodine. These results indicate that the system is very useful for nondestructively evaluating fine structures and their constituent elements.