Spectral Calibration of the Fluorescence Telescopes of the Pierre Auger Observatory

Abstract

We present a novel method to measure precisely the relative spectral response of the fluorescence telescopes of the Pierre Auger Observatory. We used a portable light source based on a xenon flasher and a monochromator to measure the relative spectral efficiencies of eight telescopes in steps of 5 nm from 280 nm to 440 nm. Each point in a scan had approximately 2 nm FWHM out of the monochromator. Different sets of telescopes in the observatory have different optical components, and the eight telescopes measured represent two each of the four combinations of components represented in the observatory. We made an end-to-end measurement of the response from different combinations of optical components, and the monochromator setup allowed for more precise and complete measurements than our previous multi-wavelength calibrations. We find an overall uncertainty in the calibration of the spectral response of most of the telescopes of 1.5% for all wavelengths; the six oldest telescopes have larger overall uncertainties of about 2.2%. We also report changes in physics measureables due to the change in calibration, which are generally small.

arXiv commentPublished version. Added journal reference and DOI. Added Report Number

References in corpus (12)

• The Pierre Auger Cosmic Ray Observatory
• Observation of the suppression of the flux of cosmic rays above 4x10^19eV
• The Fluorescence Detector of the Pierre Auger Observatory
• Performance of Wavelength-Shifting Fibers for the Mu2e Cosmic Ray Veto Detector
• The Offline Software Framework of the Pierre Auger Observatory
• The Surface Detector System of the Pierre Auger Observatory
• Measurement of the UHECR energy spectrum using data from the Surface Detector of the Pierre Auger Observatory
• Absolute Calibration of a Large-diameter Light Source
• The Pierre Auger Observatory: Contributions to the 33rd International Cosmic Ray Conference (ICRC 2013)
• Multi-wavelength Calibration Procedure for the Pierre Auger Observatory Fluorescence Detectors
• The Absolute, Relative and Multi-Wavelength Calibration of the Pierre Auger Observatory Fluorescence Detectors
• Optical Relative Calibration and Stability Monitoring for the Auger Fluorescence Detector

Cited by in corpus (2)

• High-Energy Galactic Cosmic Rays (Astro2020 Science White Paper)
• Studying the mass sensitivity of air-shower observables using simulated cosmic rays