AugerPrime: An Upgrade to the Pierre Auger Observatory

The Pierre Auger Cosmic Ray Observatory is the world's largest experiment for the detection of Ultra-High Energy Cosmic Rays (UHECR) in the energy range above 10¹⁸ eV. Auger has operated continuously since 2004 and has provided important new results for the energy spectrum, arrival directions, and energy-dependent composition information of UHECRs. While results from Auger place important constraints on the nature and origin of the highest energy cosmic rays, several key question remain unresolved.

We describe progress, plans, and expected performance of an upgraded Pierre Auger Observatory that will operate over the next decade. The upgrade, called AugerPrime, employs new scintillator and radio detectors to maximize the quality of the event-by-event probabilistic composition assignment, thereby maximizing the size of the dataset of low-Z events, and increasing the sensitivity of the Auger Observatory to high-energy neutrinos. AugerPrime will operate in concert with neutrino and gamma-ray measurements from other observatories to strongly constrain characteristics of UHECR sources and acceleration mechanisms. Furthermore, thanks to composition-assisted anisotropy studies, some individual sources of UHECR may be identified.