Source composition of cosmic ray nuclei

Abstract During propagation in the Galaxy, cosmic-ray nuclei undergo spallation and as a result, their composition at the time of acceleration gets modified. Propagation models have been used to obtain the source composition from the observed abundance. We made use of the standard leaky-box model with time as the propagation variable to examine the spectra of all elements. The main ingredients in this method are the spallation cross-sections, which has considerably changed over the time. Using the latest available cross-sections, we show that the spectral index of the power-law injection spectrum in rigidity is −2.32. We also derive the escape path-length and the source abundances. The derived abundances differ from those of Webber for some of the elements.