Nuclear Interactions and Cosmic Radiation at Energies around106GeV

The results of a series of Monte Carlo simulations of extensive air showers are compared with experimental data from the Sydney 64-scintillator array and other experiments. The work has had two main objectives: (a) the study of the composition of cosmic radiation around ${10}^6$ GeV; (b) the study of nuclear interactions at very high energies. In the first field, evidence is produced to show that the composition of cosmic radiation is much the same at ${10}^{15}$ eV total energy as at 5 × ${10}^{10}$ eV total energy. Above about 3 × ${10}^{15}$ eV the composition changes, the beam becoming progressively richer in heavier nuclei up to energies of about ${10}^{17}$ eV. In the second field, the main result reported is that at energies above ${10}^{14}$ eV there is evidence that much higher transverse momenta occur than at machine energies. If true, this implies that a force is acting which is much stronger than the normal strong interaction.