Techniques for Measuring Aerosol Attenuation using the Central Laser Facility at the Pierre Auger Observatory

Abstract

The Pierre Auger Observatory in Malargüe, Argentina, is designed to study the properties of ultra-high energy cosmic rays with energies above 1018 eV. It is a hybrid facility that employs a Fluorescence Detector to perform nearly calorimetric measurements of Extensive Air Shower energies. To obtain reliable calorimetric information from the FD, the atmospheric conditions at the observatory need to be continuously monitored during data acquisition. In particular, light attenuation due to aerosols is an important atmospheric correction. The aerosol concentration is highly variable, so that the aerosol attenuation needs to be evaluated hourly. We use light from the Central Laser Facility, located near the center of the observatory site, having an optical signature comparable to that of the highest energy showers detected by the FD. This paper presents two procedures developed to retrieve the aerosol attenuation of fluorescence light from CLF laser shots. Cross checks between the two methods demonstrate that results from both analyses are compatible, and that the uncertainties are well understood. The measurements of the aerosol attenuation provided by the two procedures are currently used at the Pierre Auger Observatory to reconstruct air shower data.

28 pages, 13 figures

References in corpus (3)

• Description of Atmospheric Conditions at the Pierre Auger Observatory using the Global Data Assimilation System (GDAS)
• Measurement of the Aerosol Phase Function at the Pierre Auger Observatory
• Description of Atmospheric Conditions at the Pierre Auger Observatory Using Meteorological Measurements and Models

Cited by in corpus (11)

• The Pierre Auger Cosmic Ray Observatory
• Depth of Maximum of Air-Shower Profiles at the Pierre Auger Observatory: Measurements at Energies above 10^17.8 eV
• Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
• Measurement of the average shape of longitudinal profiles of cosmic-ray air showers at the Pierre Auger Observatory
• Origin of atmospheric aerosols at the Pierre Auger Observatory using studies of air mass trajectories in South America
• Atmospheric multiple scattering of fluorescence light from extensive air showers and effect of the aerosol size on the reconstruction of energy and depth of maximum
• Joint Elastic Side-Scattering Lidar and Raman Lidar Measurements of Aerosol Optical Properties in South East Colorado
• Atmospheric effects in astroparticle physics experiments and the challenge of ever greater precision in measurements
• On the possiblity of using vertically pointing Central Laser Facilities to calibrate the Cherenkov Telescope Array
• The FRAM robotic telescope for atmospheric monitoring at the Pierre Auger Observatory
• Atmospheric aerosol attenuation effect on FD data analysis at the Pierre Auger Observatory