Depth profiles and resolution limits in accelerator-based solid state analysis

A ubiquitous problem in solid state analysis is the determination of the elemental composition of a sample as a function of the depth. The determination of the depth profiles from ion-beam experiments is an ill-posed inversion problem due to ion-beam and detector-induced energy spreads as well as energy-loss straggling and small-angle scattering effects. The inversion problem is solved in the framework of Bayesian probability theory, which provides a method for quantifying and combining uncertain data and uncertain additional information. By deconvolving the apparatus transfer function and modeling the scattering events in the sample we reconstructed depth profiles of (13)C in tetrahedral amorphous carbon (ta-C) and depth profiles in (12)C/(13)C marker probes. An enhancement of the energy resolution by a factor of 6 was obtained.