## 4 Imaging of Bragg-Dip Profiles and Evaluation of Detailed Inner-Grain Information  
### Measured Neutron Transmission Spectra of Three Evaluated Grains  
Figure 4 shows the results of neutron transmission imaging at each wavelength measured in the experiment and the neutron transmission spectra of three crystalline grains, Grains 1, 2 and 3, evaluated in this study. Figure 4a,c,e are neutron transmission images of Grains 1, 2 and 3 at the wavelength where (110) Bragg-dip appears. The darker regions in the images indicate that the neutron transmission intensity is lower, and it means that (110) Bragg-dip appears at the wavelength. The grain shapes can be observed in the neutron transmission images. In the neutron transmission images and IPF maps presented in the previous study [19], each grain is observed as a single crystal. In this study, for the investigation of inner defects in each grain, the single Bragg-dip profile-fitting analysis method was applied to Bragg-dips in the neutron transmission spectra of Grains 1, 2 and 3. For each grain, two Bragg-dips, indicated in Figure 4b,d,f, which are respectively caused by (110) plane and (101) plane, were analyzed. By the analysis, the Bragg-dip wavelengths, the widths of Bragg-dips and the integrated intensities of Bragg-dips were mapped at each pixel. Imaging of Appearance Wavelength of Bragg-Dip and Evaluation of Small Change in Crystal Orientation in a Grain  
Figure 5 shows the results of imaging the wavelengths where Bragg-dips of Grains 1, 2, and 3 appear. For each grain, two Bragg-dip wavelengths, \(\lambda_{bkl}\), were mapped in real space. Each Bragg-dip is caused by (110) plane and (101) plane. Here, imaging of the Bragg-dip wavelength of Grain 3 (Figure 5e,f) is discussed as an example. In Grain 3, (110) Bragg-dip appears at a relatively longer wavelength, whereas (101) Bragg-dip appears at a relatively shorter wavelength (e.g., Region (1)). In addition, (110) Bragg-dip appears at a relatively shorter wavelength, whereas (101) Bragg-dip appears at a relatively longer wavelength (e.g., Region (2)). These relations mean that the interval between the two Bragg-dips changes. This tendency was also observed in the other grains. Such a change in the interval between two Bragg-dips represents the change in the crystal orientation [13]. Here, it is considerable that the macro-strain and the residual-strain can also change the interval of the two Bragg-dips. However, the changes in the wavelengths of (110) and (101) Bragg-dips of Grains 1, 2 and 3 are about 0.1-0.6%, and these values are too large to be the changes in the wavelengths caused by the elastic-strain, such as the macro-strain and the  
Figure 4: (**a**) Neutron transmission image at the wavelength of 0.368 nm. (**b**) Neutron transmission spectrum of Grain 1. (**c**) Neutron transmission image at the wavelength of 0.378 nm. (**d**) Neutron transmission spectrum of Grain 2. (**e**) Neutron transmission image at the wavelength of 0.393 nm. (**f**) Neutron transmission spectrum of Grain 3.  
residual-strain. Therefore, in the present case, the change in the interval between the two Bragg-dips is considered as representing the change in the crystal orientation. Figure 6 shows imaging of the interval between the two Bragg-dips, (\(\lambda_{110}\)-\(\lambda_{101}\)), of Grains 1, 2 and 3, and the neutron transmission spectra of the regions where the Bragg-dip interval is wide or narrow (Regions (1)-(6)). Incidentally, in Figure 6d, a Bragg-dip appears at the wavelength of 0.39 nm on the neutron transmission spectrum at Region (5). It is the (110) Bragg-dip of Grain 3. This is because Grain 2 and Grain 3 are stacked along the neutron transmission direction in this region (see Figure 1, Region (\(\alpha\))). As shown in Figure 6a,c,e, the interval of Bragg-dips certainly changes in the same grain. Nevertheless, as shown in Figure 6b,d,f, the changes in the interval of Bragg-dips are slight.