Energy-modulated x-ray microtomography

Abstract

We describe an instrument for computerized x-ray tomography which can provide fully three-dimensional examination of small samples (a few millimeters to a few centimeters) with resolution variable from 5 to 100 μm. Elemental and chemical-state distributions are obtained with high resolution by modulating the energy of the incident x-ray beam. An essential component is the monochromator we designed and optimized for chemical microtomography. It has a narrow energy bandpass and a large degree of harmonic suppression, provides a uniform x-ray beam with small angle of divergence, and is cooled in a way that eliminates thermal and vibrational instabilities.