Acceptance of fluorescence detectors and its implication in energy spectrum inference at the highest energies

Abstract

Along the years HiRes and AGASA experiments have explored the fluorescence and the ground array experimental techniques to measure extensive air showers, being both essential to investigate the ultra-high energy cosmic rays. However, such Collaborations have published contradictory energy spectra for energies above the GZK cut-off. In this article, we investigate the acceptance of fluorescence telescopes to different primary particles at the highest energies. Using CORSIKA and CONEX shower simulations without and with the new pre-showering scheme, which allows photons to interact in the Earth magnetic field, we estimate the aperture of the HiRes-I telescope for gammas, iron nuclei and protons primaries as a function of the number of simulated events and primary energy. We also investigate the possibility that systematic differences in shower development for hadrons and gammas could mask or distort vital features of the cosmic ray energy spectrum at energies above the photo-pion production threshold. The impact of these effects on the true acceptance of a fluorescence detector is analyzed in the context of top-down production models.

References in corpus (6)

• New measurement on photon yields from air and the application to the energy estimation of primary cosmic rays
• Upper limit on the photon fraction in highest-energy cosmic rays from AGASA data
• Energy Release in Air Showers
• Primary Particle Type of the Most Energetic Fly's Eye Air Shower
• Longitudinal development of extensive air showers: hybrid code SENECA and full Monte Carlo
• Ultra High Energy Cosmic Rays Spectra in Top-Down models

Cited by in corpus (6)

• Upper limit on the cosmic-ray photon flux above 10^19 eV using the surface detector of the Pierre Auger Observatory
• Search for ultra-high energy photons using air showers
• Sensitivity of cosmic-ray experiments to ultra-high-energy photons: reconstruction of the spectrum and limits on the superheavy dark matter
• Detection of Exotic Massive Hadrons in Ultra High Energy Cosmic Ray Telescopes
• Effects of the Energy Error Distribution of Fluorescence Telescopes on the UHECR energy spectrum
• The shower size parameter as estimator of extensive air shower energy in fluorescence telescopes