Computed Tomography for Refractive Index using an X-ray Shearing Interferometer

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The object of the present investigation is to show the effectiveness of the proposed shearing interferometer and to apply it to the reconstruction of refractive index distribution using computed tomography. We obtain following results :1. We measured interferometric intensity distribution and phase distribution of the X-ray penetrated through objects made of plastics with the fabricated X-ray shearing interferometer. For the measurement, we used a point X-ray source and scintillation counter and scan the object mechanically. With this system, we can detect thickness difference as small as 1 μm, with sensitivity higher than the usual intensity detection.2. We constructed a X-ray shearing interferometer system with a line X-ray source and a CCD camera. With this system we obtain interferometric X-ray image of plastic object without mechanical scanning. By introducing phase shifting method to this system, we measured phase difference distribution of X-ray penetrated through objects made o … More f plastics.3. We analyzed the beam width in the interferometer with the spherical wave-front theory of X-ray dynamic diffraction and show that the attainable spherical resolution of the shearing interferometer is a few micron.4. We constructed interferometers which were planned to make separated type, but the interferometer did not work well perhaps because the residual stress in the Si crystal. We find another method of making the interferometer and are under way to make it. Phase difference measurements in this project are made with the old interferometer. .5. We made a program for calculating the refractive index distribution from the obtained phase distribution and investigate the possibility of CT reconstruction with the fabricated X-ray shearing interferometer by simulation.6. We showed effectiveness of the shearing interferometer by reconstructing dynamic refractive index distribution on a section of a fluid flow with a grating shearing interferometer in the visible spectrum and CT algorithm.7. We obtain axially symmetrical refractive index distribution from the data taken with the X-ray shearing interferometer Less