抄録
A projection microtomographic system using synchrotron radiation with the spatial resolution of about 1 μm has been developed at SPring-8. The quantitative relation between CT-values and linear attenuation coefficients of materials has been obtained empirically in this system. Materials (minerals) can be estimated from the CT values using this relation. The relation also made possible to obtain three-dimensional concentration distributions of some elements by subtraction method. The microtomographic system was applied to extraterrestrial samples, such as meteorites and cosmic dust. This system is also useful to samples those will be returned by spacecrafts in the Hayabusa mission by JAXA and Stardust mission by NASA.