Spectral Features and Masses in the PeV Region

An analysis is made of the masses and spectral features for cosmic rays in the PeV region, insofar as they have a bearing on the problem of the interaction of cosmic ray particles. In our Single Source Model we identified two 'peaks' seen in a summary of the world's data on primary spectra, and claimed that they are probably due to oxygen and iron nuclei from a local, recent supernova. In the present work we examine other possible mass assignments. We conclude that of the other possibilities only Helium and Oxygen (instead of O and Fe) has much chance of success; the original suggestion is still preferred, however. Concerning our location with respect to the SNR shell, the analysis suggests that we are close to it - probably just inside.