Non-Rutherford backscattering spectrometry (NRBS)
In RBS one assumes a pure Coulomb process in which scattering occurs between two completely unscreened nuclear point charges. When the collision diameter is very small and becomes comparable to the sum of the nuclear radii of the projectile and the target atom, the finite sizes of the nuclei and the nuclear force interactions lead to deviations from the Rutherford scattering cross section. For MeV ion beams, this phenomenon can be observed in low Z projectile/target system where the Coulomb barrier is small. The cross-section for such nuclear resonance scattering can be many times greater than the Rutherford values. (http://www-nds.iaea.org/ibandl/) Such non-Rutherford scattering has been used to some extent for the detection of light elements (C, N, O, Si) in heavy matrixes.