Galactic Cosmic Rays, Cosmic-Ray Variations, and Cosmogenic Nuclides in Meteorites

Abstract We present a new generation of model calculations for cosmogenic production rates in various types solar system bodies. The is based on the spectra primary and secondary particles calculated using INCL++6 code, which most reliable sophisticated code available spallation reactions. Thanks to recent improvements (extending lower higher energies considering light charged as ejectiles projectiles), we can first time directly consider Galactic ? particles. calculate 22 Na, 10 Be, 26 Al an L-chondrite with radius 45 cm Apollo 15 drill core, determine long-term average cosmic-ray (GCR) spectrum (represented by modulation potential ?) meteoroid orbits at ?3 au ? = 600 MV 1 au, i.e., Earth Moon 660 MV. From this, GCR gradient inner ?5% ?1 . Finally, discuss possibility studying temporal variations rate ratios short- long-lived radionuclides.