Air fluorescence measurements in the spectral range 300-420 nm using a 28.5 GeV electron beam

TL;DR

This study measures the fluorescence yield and spectrum in air caused by a high-energy electron beam, providing data relevant for cosmic ray detection in the 300-420 nm range.

Contribution

It presents new measurements of fluorescence yield and spectrum in air at high energies, calibrated with Rayleigh scattering, for the first time in this specific spectral range.

Findings

Fluorescence yield at atmospheric pressure is 20.8 photons per MeV.

Spectrum of fluorescence spans 300-420 nm.

Calibration achieved using Rayleigh scattering of a nitrogen laser.

Abstract

Measurements are reported of the yield and spectrum of fluorescence, excited by a 28.5 GeV electron beam, in air at a range of pressures of interest to ultra-high energy cosmic ray detectors. The wavelength range was 300 - 420 nm. System calibration has been performed using Rayleigh scattering of a nitrogen laser beam. In atmospheric pressure dry air at 304 K the yield is 20.8 +/- 1.6 photons per MeV.