## 4 Results and Discussion  
The functionality of the presented software application was verified by RBS/C measurement of the Si (100) crystal. The focused beam of helium ions interacted with the Si sample mounted on the goniometer in the vacuum chamber of the ion beam analysis end-station. Two-stepping modes were used to obtain the coarse and fine channeling measurement. We determined the initial offset position based on coarse measurement, that allows the crystal sample alignment. By using the stepping mode B of the goniometer, the major axis offset was found to be dTheta = \(-\)0.05\({}^{\circ}\) and dTilt = 0.17\({}^{\circ}\) (Figure 16). Thereafter, accurate and detailed data were acquired from the fine channeling measurement.  
All of the forementioned energy and angular spectra present data from this test measurement. In case of coarse measurement backscattering counts were collected every 0.2\({}^{\circ}\) across intervals from \(-\)4.0\({}^{\circ}\) up to +4.0\({}^{\circ}\) in the theta plane. The use of two stepping modes (Figure 12) revealed the mechanical backslash of the goniometer in the mode A and the direction of Theta 0.2\({}^{\circ}\) and Tilt < 0.02\({}^{\circ}\). This systematic error caused by backslash in the  
Figure 17: Normalized yield of a fine measurement with measured and calculated values. The channeling dip features a reduction in ROI counts by a factor 0.32 with a FWHM width of 0.90\({}^{\circ}\).  
direction of Theta was eliminated by the mode B as the following results demonstrate. To compare both of the implemented stepping modes of the goniometer (Figure 12):  
* In Figure 18 there are scattered intersections of planar axes (calculated based on the intersection positions of main axes of the crystallographic planes displayed in Figure 16 and their distance from the origin of coordinate system), where we can see the dispersion of points for both modes of generating steps.
* We calculated the dispersion for the intersection points of planes as it is shown in Table 3.  
The result confirms our assumption, that the mode B provided over 3 times more accurate measurement.  
After crystal alignment, angular measurement through the (100) main axis was done. Measured planes and the main axes of crystal (Figure 16) are consistent with stereographic projection for Si (100) in [19] and expected as shown in Figure 4. Subsequently, the channel (angular) width of 0.90 \(\pm\) 0.07\({}^{\circ}\) and the minimum dip (\(\chi_{\text{min}}\) = 0.32 \(\pm\) 0.03) was determined from the normalized angular plot (Figure 17). Designed application automates numerous  
Figure 18: Points of intersections of planar axes measured by both mode A (blue points) and B (red points).  
\begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Mode**} & \multicolumn{2}{c}{**Dispersion**} \\ \cline{2-3}  & **Theta Angles** & **Tilt Angles** \\ \hline mode A & 0.253 \(\pm\) 0.103 & 0.284 \(\pm\) 0.116 \\ mode B & 0.072 \(\pm\) 0.029 & 0.073 \(\pm\) 0.030 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Centroid and dispersion of planes intersections.  
measurements and automatically sets the position of the goniometer, the functionality of which we verified on the experiment and sample.