AugerPrime: Status and first results

TL;DR

AugerPrime enhances the Pierre Auger Observatory with new detectors and upgrades, enabling detailed measurements of cosmic-ray primary mass and providing initial results that deepen understanding of ultra-high-energy cosmic rays.

Contribution

This paper reports the deployment and commissioning of AugerPrime's new detectors and electronics, marking a significant upgrade for detailed cosmic-ray composition analysis.

Findings

Successful installation and commissioning of new detectors

Improved measurement capabilities for primary mass

First results demonstrating enhanced observatory performance

Abstract

With the knowledge and statistical precision derived from two decades of measurement, the Pierre Auger Observatory has significantly deepened our understanding of ultra-high-energy cosmic rays while unearthing an increasingly complex astrophysical landscape and exposing tensions with hadronic interaction models. The field now demands the mass of individual cosmic-ray primaries as an observable with an exposure that only the 3000-square-kilometer surface array of the Observatory can provide. Access to the primary mass hinges on the disentanglement of the electromagnetic and muonic components of extensive air showers. To achieve this, scintillator and radio detectors have been installed atop each existing water-Cherenkov detector of the surface array, whose dynamic range has also been enhanced through the installation of small-area PMTs. Additionally, the timing and signal resolution of all detector stations have been improved through upgraded station electronics, and underground muon counters have been installed in a region of the array with denser spacing. As the commissioning of the final components of AugerPrime reaches its conclusion and the enhanced array comes fully online, we present the realization of its design, its performance, and the first results from this now multi-hybrid observatory.