Energy Dependence of Air Fluorescence Yield measured by AIRFLY

TL;DR

This study measures the air fluorescence yield across a wide range of electron energies to verify its proportionality to energy deposition, crucial for accurate cosmic ray detection.

Contribution

The paper provides experimental data confirming the proportionality of fluorescence yield to energy deposit in air over a broad energy range, supporting cosmic ray energy measurements.

Findings

Fluorescence yield proportionality holds within a few percent across measured energies.

Measurements span from keV to hundreds of MeV electron energies.

Results support the reliability of fluorescence detection in ultra high energy cosmic ray studies.

Abstract

In the fluorescence detection of ultra high energy (> 10**18 eV) cosmic rays, the number of emitted fluorescence photons is assumed to be proportional to the energy deposited in air by shower particles. We have performed measurements of the fluorescence yield in atmospheric gases excited by electrons over energies ranging from keV to hundreds of MeV in several accelerators. We found that within the measured energy ranges the proportionality holds at the level of few %.