The mass spectrometry is one of the most powerful characterization methods in materials processing technologies. RBS and SIMS have been used extensively for the determination of stoichiometry and impurity distributions of materials. Even if the sensitivity is low, RBS provides accurate identification of the atomic masses and surface depth profiling of the elements. On the contrary, SIMS is very sensitive although the quantitative determination of the composition and local order structure of the material surface is difficult. On the basis of these characteristics, RBS is thought to be the absolute measurement technique, and SIMS the relative measurement technique. The material characteristics can be analogized from material elements, that are determined by the absolute and relative measurement technique.