Air Fluorescence Relevant for Cosmic-Ray Detection - Review of Pioneering Measurements

TL;DR

This review summarizes pioneering laboratory measurements of air fluorescence light yield, which is crucial for accurately determining the energy of ultra-high-energy cosmic rays via air shower observations.

Contribution

It compiles and analyzes historical fluorescence light yield measurements from 1954 to 2000, highlighting their importance for cosmic-ray detection.

Findings

Historical measurements established baseline fluorescence yields.

Laboratory experiments have improved understanding of fluorescence mechanisms.

Uncertainty in fluorescence yield remains a key factor in cosmic-ray energy calibration.

Abstract

Cosmic rays with energies exceeding $10^{17}$ eV are frequently registered by measurements of the fluorescence light emitted by extensive air showers. The main uncertainty for the absolute energy scale of the measured air showers is coming from the fluorescence light yield of electrons in air. The fluorescence light yield has been studied in laboratory experiments. Pioneering measurements between 1954 and 2000 are reviewed.