Isotopic variations of some rare earth elements in extraterrestrial materials influenced by the cosmic-ray irradiation and their cosmochemical applications

Abstract

Thermalized neutrons arising at the surface of solar planets are produced from the interaction of cosmic rays with the nucleus consisting of surficial materials. The neutron energy spectrum in the range between thermal and epithermal regions at the surface of the material can be investigated based on the combination of the isotopic variations of Sm and Gd caused by the thermal neutron-capture reactions in our previous study, with those of Dy, Er, and Yb caused by the epithermal neutron-capture reactions.