Production rates of cosmogenic helium isotopes in iron meteorites

Abstract

The production rates, P, of cosmogenic 3He and 4He in iron meteorites can be described by introducing empirically determined effective mass difference, ΔA, terms in the general formula for the total isobaric yield of cosmogenic nuclides of mass A: P(A) = k 1 ′ · (ΔA + 4) −k 2 ′ , ΔA = 56 − A, covering A = 54 − 20. It is found that: P( 3He) = 16.7 · k 1 ′ · (22) −k 2 ′ and P( 4He) = 18.3 · k 1 ′ · (14) −k 2 ′ .