부산대학교 도서관

We describe the experimental technique being developed at the bending magnet beamline 2-BM at the Advance Photon Source, which allows in situ measurement of x-ray microtomography and x-ray diffraction. With the combined use of a double crystal monochromator (dE/E∼10[sup -4]) and double multilayer monochromator (dE/E∼5×10[sup -2]), we have the capacity to make diffraction measurements with high energy resolution and tomography measurements with increased flux. The tomography-diffraction technique has application for studying deformation or fracture process in engineering materials where the measurements both in the real space (e.g., three dimensional mapping of cracks) and in the reciprocal space (e.g., peak shift and broadening due to strain) are extremely valuable. Combining these two complimentary techniques under the same experimental setup can bring the added advantage that both the propagation of cracks and the strains around the cracks can be measured while the specimen is under load. With the high-throughput data acquisition system and a cluster-based parallel computing system, topographic data acquisition and reconstruction of the 512×512×512 voxel sample with a few micron resolution can be obtained in less than 10 min. The x-ray diffraction measurement is performed using a charge coupled device (CCD) camera mounted on two orthogonal linear stages. This offers tracking capability of the diffracted beam to eliminate the systematic errors associated with the measurements of diffraction pattern at fixed distance from the sample. The CCD pixel size of 22.5 μm provides a strain resolution better than 10[sup -4] for most engineering materials. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]