請幫我翻譯下這段英語（人工翻譯）
A typical scattering experiment involves a beam with many incident particles all with the same kinetic energy. The coordinate system is shown in Figure 5.7. The incident particles come from the left with an initial velocity v in the +x direction. We take the center of the beam and the center of the target to be on the x-axis. The impact parameter b is the perpendicular distance from the initial trajectory to a parallel line through the center of the target (see Figure 5.7). We assume that the width of the beam is larger than the size of the target. The target contains many scattering centers, but for calculational purposes, we may consider scattering off only one particle if the target is sufficiently thin.