RBS Theory: Scattering Cross Sections

The relative number of particles backscattered from a target atom into a given solid angle for a given number of incident particles is related to the differential scattering cross section. The scattering cross section is basically proportional to the square of the atomic number of the target atom.

The illustration shows relative yields for He backscattering from selected elements at an incident He energy of 2 MeV. The energies for He backscattering from these elements when present at the surface of a sample are also displayed. The graph indicates that RBS is over 100 times more sensitive for heavy elements than for light elements, due to the larger scattering cross sections of the heavier elements.

[Previous Topic] [Next Topic]