Theoretical Considerations of the Three-Level Maser Detector for the Far-Infrared

Abstract

Experimental results from Haverah Park, Yakutsk, AGASA and Fly's Eye are reviewed. All these experiments work in the energy range above 10 17 eV. The 'dip' structure around 10 18.5 eV in the energy spectrum is well established by all the experiments, though the exact position differs slightly. Fly's Eye and Yakutsk results on the chemical composition indicate that the cosmic rays are getting lighter over the energy range from 10 17 eV to 10 19 eV, but the exact fraction is hadronic interaction model dependent, as indicated by the AGASA analysis. The arrival directions of cosmic rays are largely isotropic, but interesting features may be starting to emerge. Most of the experimental results can best be explained with the scenario that an extragalactic component gradually takes over a galactic population as energy increases and cosmic rays at the highest energies are dominated by particles coming from extragalactic space. However, identification of the extragalactic sources has not yet been successful because of limited statistics and the resolution of the data. § Present address: Rosetta Inpharmatics,Dip 2nd Knee Figure 1. A schematic drawing of the energy spectrum of cosmic rays above 10 14 eV.