Cosmic Rays in the Energy Range 1014?1017 eV

Abstract

Aust. J. Phys., 1980,33,911-21 It is possible to explain the gross features of extensive air showers using very different alternative assumptions about the character of particle interactions, provided that different assumptions are made about the primary particle flux and composition. From this fact it is first shown that a very consistent set of fairly direct measurements on primary flux now exists (subject to the acceptance of a systematic bias in one set of data), together with constraints on the composition. (Protons and other nuclei however turn out not to have the same rigidity spectrum.) The gross features of showers mostly fit a scaling model with rising cross sections, but there are contrary indications (particularly from y-ray flux, particle spread and core structure at the higher energies) that a change in the nature of interactions occurs above 10 '5 eV, and this puzzle has not been solved.

Comment on the Cosmic Ray Energy Spectrum in the Light of Results from Atmospheric Cerenkov Studies

“…1 where shower primary energy Ep and sea-level size NeSL are related to depth of shower maximum. Since the shower size spectrum (size against integral intensity) is well known (Hillas 1975;Clay and Gerhardy 1982), we can also relate an intensity I to a depth of shower maximum through the shower size. This re.lationship is also shown in Fig.…”

“…We conclude that the results from the Cerenkov work are reasonable. the shower size spectrum and the assumption that shower size at maximum is proportional to primary energy, (c) by Hillas (1980). Since Fig.…”

“…The resulting spectrum (A) is shown in Fig. 2 together with a spectrum (c) derived by Hillas (1980) from other (non-Cerenkov) data. These spectra differ appreciably and we wish to check our Cerenkov-derived spectrum.…”

“…Development near maximum does not affect this result provided that, in terms of absorber depth (in g cm -2), average development progresses similarly in both cases. This assumption appears to be borne out by calculated development curves such as those by Hillas (1980). In the restricted showersize range of interest, the available data (e.g.…”

Cosmic Ray Anisotropy and the Knee of the Energy Spectrum

“…Hillas 1980). It would appear that a power law is only useful as a first approximation to the spectrum.…”