High Quantum Efficiency Phototubes for Atmospheric Fluorescence Telescopes

TL;DR

This paper explores how high quantum efficiency phototubes can enhance atmospheric fluorescence telescopes by increasing aperture, improving measurement quality, and enabling more compact designs for ultra-high energy cosmic ray detection.

Contribution

It presents recent advancements in high quantum efficiency phototubes and demonstrates through simulations their potential to improve telescope performance for cosmic ray observations.

Findings

Higher aperture and increased detection statistics.

Improved reconstruction quality of air shower data.

Potential for more compact telescope designs.

Abstract

The detection of atmospheric fluorescence light from extensive air showers has become a powerful tool for accurate measurements of the energy and mass of ultra-high energy cosmic ray particles. Employing large area imaging telescopes with mirror areas of 10m2 or more, showers out to distances of 30km and more can be observed. Matrices of low-noise photomultipliers are used to detect the faint light of the air showers against the ambient night-sky background noise. The signal-to-noise ratio of such a system is found to be proportional to the square root of the mirror area times the quantum efficiency of the phototube. Thus, higher quantum efficiencies could potentially improve the quality of the measurement and/or lead to the construction of more compact telescopes. In this paper, we shall discuss such improvements to be expected from high quantum efficiency phototubes that became available on the market only very recently. A series of simulations has been performed with data of different types of commercially available high quantum efficiency phototubes. The results suggest a higher aperture and thus increased statistics for such telescopes. Additionally, the quality of the reconstruction can be improved.