The upper end of the observed cosmic ray energy spectrum

Abstract

The Sydney giant air shower array has been in operation now for approximately five years. The authors analyse the first 10000 showers observed and derives a muon size and total energy spectrum. The area time product involved for these data is about 175 km² yr and the threshold energy for these showers is about 10¹⁷ eV. The detection probability of the array is carefully analysed by simulated showers and associated errors are assessed. The resulting energy spectrum is derived using a variety of shower development models from both Sydney and Haverah Park. Latest Monte Carlo and analytical air shower calculations provide the necessary link between the observed number of muons and the primary energy.