TITLE:
The Energy Spectrum of Ultraheavy Nuclei above 1020 eV
AUTHORS:
Antonio Codino
KEYWORDS:
Ankle Energy, Ultra-High Energy, GZK Effect, Ultraheavy Nuclei
JOURNAL NAME:
Journal of Applied Mathematics and Physics,
Vol.5 No.8,
August
25,
2017
ABSTRACT: A major feature of the energy spectrum of the cosmic radiation above 1019 eV is the increasing fraction of heavy nuclei with respect to light nuclei. This fact, along with other simple assumptions, is adopted to calculate the energy spectrum of the cosmic radiation up to 2.4 × 1021 eV. The predicted spectrum maintains the index of 2.67 observed at lower energies which is the basic, known, empirical well-assessed feature of the physical mechanism accelerating cosmic rays in the Galaxy. Indeed above 1019 eV the injection of nuclei is inhibited by some filter and this inhibition causes a staircase profile of the energy spectrum. It is argued that particle injection failure versus energy commences with protons, followed by Helium and then by other heavier nuclei up to Uranium. Around 7.5 × 1020 the cosmic radiation consists solely of nuclei heavier than Copper and the estimated intensity is 1.8 × 10-30 particles/GeV s sr m2.