Performance of the 433 m surface array of the Pierre Auger Observatory

Discussion timeslot (ZOOM-Meeting): 15. July 2021 - 18:00
ZOOM-Meeting URL: https://desy.zoom.us/j/92210078166
ZOOM-Meeting ID: 92210078166
ZOOM-Meeting Passcode: ICRC2021
Corresponding Session: https://icrc2021-venue.desy.de/channel/07-Where-to-go-in-UHECR-observations-CRI/123
Live-Stream URL: https://icrc2021-venue.desy.de/livestream/Discussion-03/4

Abstract:
"The Pierre Auger Observatory, located in western Argentina, is the world's largest cosmic-ray observatory. While it was originally built to study the cosmic-ray flux above $10^{18.5}$ eV, several enhancements have reduced this energy threshold. One such enhancement is a surface array composed of a triangular grid of 19 water-Cherenkov detectors separated by $433$ m (SD-433) to explore the energies down to about $10^{16}$ eV. We are developing two research lines employing the SD-433. Firstly, we will measure the energy spectrum in a region where previous experiments have shown evidence of the second knee. Secondly, we will search for ultra-high energy photons to study PeV cosmic-ray sources residing in the Galactic center. In this work, we introduce the SD-433 and we show that it is fully efficient above $5times 10^{16}$ eV for hadronic primaries with $theta smaller 45,^{text{o}}rn$. Using seven years of data, we present the parametrization of the lateral distribution function of measured signals. Finally, we show that an angular resolution of $ang{1.8}$ ($ang{0.5}$) can be attained at the lowest (highest) primary energies. Our study lays the goundmark for measurements in the energy range above $10^{16}$ eV by utilizing the SD-433 and thus expanding the scientific output of the Auger surface detector."

Authors: Gaia Silli
Co-Authors: For the Pierre Auger Collaboration
Collaboration: Auger

Indico-ID: 636
Proceeding URL: https://pos.sissa.it/395/224