Cosmic ray produced nitrogen in extra terrestrial matter

Abstract

Production rates of15N by both solar cosmic rays (SCR) and galactic cosmic rays (GCR) have been calculated for moon, as well as meteorites of various sizes. Our production rates of ¹⁵N which considered both the reaction channels ¹⁶O(p, pn)¹⁵O and¹⁶O(p, 2p)¹⁵N separately are about 30% higher than those by Reedy (1981) who considered only the channel ¹⁶O(p, pn)¹⁵O and used an empirical scaling factor to estimate the contribution from ¹⁶O(p, 2p)¹⁵N. Production ratio¹⁵N²¹ Ne is composition dependent and hence is different for various silicate minerals. Additionally the ratio ¹⁵N/²¹Ne is very sensitive to the energy spectrum of the cosmic rays. This fact can be made use of in characterizing as well as in decoupling the SCR and GCR effects in extraterrestrial samples.