Current status and desired precision of the isotopic production cross sections relevant to astrophysics of cosmic rays: Li, Be, B, C, and N

The precision of the current generation of space-based cosmic-ray experiments, such as AMS-02, PAMELA, CALET, and ISS-CREAM, is now reaching ≈1--3%, from energies of GeV/nucleon to multi-TeV/nucleon. These and future measurements of the isotopic composition and energy spectra of cosmic rays may reveal signatures of as-yet unknown phenomena in a wide range of topics, provided that the currently large uncertainties of 20--50% in many of the isotopic production cross sections can be reduced. This paper provides a systematic study of the reaction channels to produce particular isotopes and identifies the most important channels for reducing the present uncertainties. It provides a first road map for planning new measurement campaigns worldwide to reach the desired uncertainties.