2007/04/30 by S. BenZvi, S. Y. BenZvi, B. Connolly +7 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Aerosol #Air shower #Astrophysics #Astrophysics and Cosmic Phenomena #Atomic physics #Auger #Cherenkov radiation #Cosmic ray #Dark Matter and Cosmic Phenomena #Detector #Observatory #Optics #Physics #Pierre Auger Observatory #Precipitation Measurement and Analysis #astro-ph #physics.ao-ph
paper · pdf · doi:10.1016/j.astropartphys.2007.06.005
published as Astropart.Phys.28:312-320,2007 · 19 pages, 10 figures (4 in color), replaced with version accepted for publication in Astroparticle Physics
openalex publication_date 2007/06/30 · arxiv created 2007/07/02 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Air fluorescence detectors measure the energy of ultra-high energy cosmic rays by collecting fluorescence light emitted from nitrogen molecules along the extensive air shower cascade. To ensure a reliable energy determination, the light signal needs to be corrected for atmospheric effects, which not only attenuate the signal, but also produce a non-negligible background component due to scattered Cherenkov light and multiple-scattered light. The correction requires regular measurements of the aerosol attenuation length and the aerosol phase function, defined as the probability of light scattered in a given direction. At the Pierre Auger Observatory in Malargue, Argentina, the phase function is measured on an hourly basis using two Aerosol Phase Function (APF) light sources. These sources direct a UV light beam across the field of view of the fluorescence detectors; the phase function can be extracted from the image of the shots in the fluorescence detector cameras. This paper describes the design, current status, standard operation procedure, and performance of the APF system at the Pierre Auger Observatory.