Medium energy nuclear data to understand the interactions of cosmic ray particles with matter

The investigation of so-called cosmogenic nuclides, which are produced by the interaction of solar and galactic cosmic ray particles with terrestrial and extraterrestrial matter, is a field of science, for which availability of reliable medium energy nuclear data is a basic requirement. The needs of this application are typical for a large number of other applications in science and technology. For the interpretation of the observed abundances of cosmogenic nuclides experimental thin-target cross sections for the production of a wide range of stable and radioactive nuclides by all contributing particle types (p, n, 4He, ...) over the entire medium-energy range provide the fundamental data base. Reliable calculational methods which allow for a priori calculation of cross sections are required to predict unknown cross sections. Primary and secondary particle fields in the irradiated materials have to be calculated by codes describing the intra- and internuclear cascades and the transport of particles from the GeV region down to zero energy. On the basis of the cross sections of the underlying nuclear reactions and of the description of primary and secondary particle fields, model calculations can be performed which allow to interpret cosmogenic nuclide abundances in terms of the history of the irradiated material as well as of the cosmic radiation itself. This information cannot be obtained by any other means. However, because of some ambiguity in these interpretations simulation and bench mark experiments play an outstanding role to validate the calculational methods. In this work all these aspects are reviewed. The status of experimental and theoretical investigations is described, a survey on the present cross section data base is presented and the future requirements with respect to further experimental and theoretical work, to compilation and critical evaluation and to international collaboration, are discussed in detail. (author). Refs, 21 figs, 1 tab