International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators
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AP/AM-07 Application of Neutron Transmission Spectroscopic Imaging for Analysis of Texture in Materials for Industrial Use Y.K. Kiyanagi, T. Kamiyama, H. Satoh, and O. Takada Graduate School of Engineering, Hokkaido University, Sapporo, Japan Corresponding Author: kiyanagi@qe.eng.hokudai.ac.jp Energy dependent imaging can obtained at one measurement in the pulsed neutron source since the neutron energy can be analyzed by time–of–flight method coupled with a 2-dimensional position sensitive detector. Therefore, spectroscopic transmission imaging using an accelerator based pulsed neutron source is very useful for obtaining not only the different contrast imaging but also the information of the texture depending on the position. The total neutron cross section depends on crystal structure, crystallite size, crystallite orientation and so on. They appear as different shapes and value of the cross section around Bragg edge. In the high wavelength resolution measurements we can observe the shift of the Bragg edges, and get the distribution of the strain. We are now under developing this method and applying to some nuclear materials. Here, we present results we obtained so far. For establishing the method it is necessary to evaluate the correlation between the cross section change and the texture change. Therefore, we performed model experiments to clarify the relations. It became clear that the larger the grain size is, the smaller the cross section around Bragg edges and the anisotropic distribution of grain orientation causes the round shape Bragg edges. By measurements on a bended stainless steel we clearly observed the effect, and also the strain distribution in the stainless steel. As an application of this method we observed the precipitation process of γ-phase of Pb-Bi to study the expansion effect, which is the candidate for coolant of ADS and a spallation target. We observed the spatial dependent distribution of crystal structure and the cooling speed dependence of the expansion. The transmission spectroscopy method using an accelerator based neutron source has proved to be useful tool for material analysis.
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