A new method for detecting heavy cosmic ray component above the knee region

Abstract

The precise energy spectrum of cosmic rays with different compositions is crucial for studying the origin of cosmic rays (CRs). Spectral features of single-component spectra provide an opportunity to investigate the acceleration and propagation of the “knee”. Ground-based experimental measurements of secondary particles are influenced by energy components and hadronic interactions, leading to significant uncertainties in component-specific energy spectra. The intensity of the direct Cherenkov (DC) light emitted by the primary cosmic ray particles is proportional to the square of their charge ($Z^2$), which serves as a valuable parameter for component discrimination. The fluorescence yield is proportional to the energy of primary cosmic ray, which can be used to reconstruct the primary particle’s energy. This project proposes a new method for measuring heavy components at the knee region: hybrid measurements combining direct Cherenkov and fluorescence detection at the high altitudes of the stratosphere. In this paper, the characterization of direct Cherenkov and fluorescence at high altitudes has been investigated, and a conceptual detector has been proposed based on the results of the study. Finally, preliminary simulation results indicate that the aperture is 85.98 $m^2\mathrm{sr}$ and retention ratio for Fe is approximately $0.8153\pm 0.0017$.