A new air shower array in the Southern Hemisphere looking for the origins of Cosmic rays: the ALPACA experiment

TL;DR

The ALPACA experiment in Bolivia aims to explore the origins of cosmic rays in the Southern Hemisphere by building a large air shower array, with initial observations including the moon shadow in cosmic rays.

Contribution

This paper introduces the ALPAQUITA prototype array, its current status, and plans for extension, marking a significant step in Southern Hemisphere cosmic ray research.

Findings

Detection of moon shadow in cosmic rays

Status update of ALPAQUITA prototype

Plans for expanding the array

Abstract

The Tibet AS$\gamma$ experiment successfully detected sub-PeV $\gamma$-rays from the Crab nebula using a Surface Array and underground muon detector. Considering this, we are building in Bolivia a new experiment to explore the Southern Hemisphere, looking for the origins of cosmic rays in our Galaxy. The name of this project is Andes Large area PArticle detector for Cosmic ray physics and Astronomy (ALPACA). A prototype array called ALPAQUITA, with $1/4$ the total area of the full ALPACA, started observations in September $2022$. In this paper we introduce the status of ALPAQUITA and the plans to extend the array. We also report the results of the observation of the moon shadow in cosmic rays.