Fig. 10

Color contour plot illustrating an example of the two-dimensional profile of the ion beam current measured with the beam-profile monitor. The incident ion particle species is \({\text{O}}^{+}\) created from the oxygen molecular gas. The beam current was measured with the 0.5 mm aperture profile monitor swept at a spatial interval of 1 mm in the x-axis direction and 0.002 mm in the y-axis. The measured current density is normalized with the total current two-dimensionally integrated over the indicated x–y plane. The color contour indicates the normalized current density in a unit of \({\text{m}}{\text{m}}^{-2}\) linearly interpolated between the x- and y-grids