High energy cosmic ray mass spectroscopy .2. Masses in the range 10(14)-10(17) eV

In earlier papers we made the case for there being two peaks in the extensive air shower (EAS) size spectra in the size range 5.10(5)-10(7) particles which we identified, somewhat tentatively, with, respectively, the CNO group of nuclei and Fe nuclei. Here, the problem of the mass composition is looked at in more detail. From an analysis of the sharpness of the first peak and its separation from the second we conclude that the 'CNO' group in the 'single source' spectrum comprises mainly oxygen nuclei, a conclusion that is consistent with a single local, recent supernova having provided the acceleration via shocks in the hot interstellar medium. (C) 1997 Elsevier Science B.V.