Depth resolution and narrow nuclear resonance profiling

Abstract

Abstract The basic stochastic theory of narrow nuclear resonance profiling is presented. We show that nm depth resolution is achievable in some cases. It is shown that the usual notions of depth resolution such as the full width at half maximum of the instrument function, adequate for instrument functions which vary only slowly over the depth range corresponding to the depth resolution, are unsatisfactory for narrow resonance profiling in the near surface region. Here, the system response to a delta function concentration profile varies very rapidly. However, the shape of the excitation curve is very sensitive to certain kinds of small changes in the concentration profile in the surface region. We discuss some first efforts to define a more general concept for depth resolution, consistent with the usually used definitions, intended to adequately express the perceived sensitivity of a measured excitation curve to variations in the underlying concentration profile.