Development of Computer Tomography System for the Soft X‐ray Microscope at Ritsumeikan University

A synchrotron‐based full‐field imaging soft x‐ray microscope was tuned appropriately to perform computer tomography. The contrast and focal depth of the optical system were evaluated by using a Fresnel zone plate as a test object of variable spatial frequency. A focal depth of 15 μm was obtained at the spatial frequency of 4.3 μm−1 according to Rayleigh’s criterion. As a first trial of three‐dimensional observation using this system, the cerebral cortex of the brain of a mouse, trimmed to a columnar shape by focused ion beam milling, was studied using a wavelength of 1.87‐nm.