Auger@TA: Deploying an independent Pierre Auger Observatory SD array at the Telescope Array Project*

The Pierre Auger Observatory and the Telescope Array (TA) are the two largest ultra-high-energy cosmic ray observatories in the world. They operate in the Southern and Northern hemispheres, respectively, at similar latitudes, but with different surface detector (SD) designs. This difference in detector design changes their sensitivity to the various components of extensive air showers. The over-arching goal of the Auger@TA working group is to cross-calibrate the SD arrays of the two observatories via a self-triggering micro-Auger-array inside the TA array, in order to identify or rule out systematic causes for the apparent differences in the flux measured at Auger and TA.

This micro-array consists of eight Auger stations, seven of which use a prototype configuration and form a single hexagon with a traditional 1.5 km Auger spacing. The 8th station is of the standard Auger configuration and is placed at the center of the hexagon, along with a TA station to form a triplet. Each Auger station will also be outfitted with an AugerPrime Surface Scintillator Detector. A custom made communication system using readily available components will be used to provide access to the stations directly via the internet. The deployment of the micro-array was carried out at the end of September 2022 and will be reported on in this talk. A simulation study was carried out to gauge the expected performance of the Auger@TA micro-array; trigger efficiencies and event rates derived from this study will be reported.