One of the major advantages of using wide-angle scattering-yield measurements to study channeling is the possibility for confining the observed yield to a thin zone at a chosen, variable depth beneath the target surface. The thickness of this thin zone is, at least at a not too large depth, proportional to the energy resolution of the experimental apparatus used, i.e. that it is usually proportional to the energy resolution of the applied particle detector. In the present paper is described the application of a magnetic particle spectrometer which, in a random substance, yields a depth resolution of ∼15 −30Å. Although this depth resolution loses some of its relevance when channeling occurs, it is possible to study details of channeling which are inaccessible in measurements where a solid-state detector is used. An example of this is demonstrated in an investigation of one single collision between particles and atomic strings and planes.