spase://NASA/NumericalData/ISEE3/IsotFrac

This data product consists of a single ASCII file containing values and their uncertainties for isotopic fractions of 56 specific isotopes relative to isotope-integrated elemental abundances, for 15 elements (Be, B, N, S, Cl, Ar, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni). Between this data product and a companion product with isotopic abundance ratios, isotopic composition information is given for 21 chemical elements. The fractions are based on 1978-1981 observations of ~50-500 MeV/n cosmic rays by the U. Chicago cosmic ray experiment on ISEE 3. Each of the ratios is linked in the ASCII file to the publication where its derivation is discussed.