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arXiv · 2208.14659

The ALPACA experiment: The project of the first sub-PeV gamma-ray observation in the southern sky

T. Kawashima·The ALPACA Collaboration
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Abstract

The ALPACA experiment is a project aiming to observe sub-PeV gamma rays for the first time in the southern hemisphere. The main goal of ALPACA is to identify PeVatrons, the accelerators of Galactic PeV cosmic rays, by observing sub-PeV pion-decay gamma rays generated in interactions between PeV cosmic rays and the interstellar medium. This new air shower experiment is located at an altitude of 4,740 m above sea level in the middle of Mt. Chakartaya in Bolivia. The air shower array consists of 401 scintillation counters covering an 83,000 m$^2$ surface area. In addition, a water-Cherenkov-type muon detector array with an area of 3,700 m$^2$ is installed to discriminate gamma rays from background cosmic rays. The prototype array ALPAQUITA will start data taking in 2022 and will extend to ALPACA in 2024. We report on a general introduction to ALPACA, the progress of the project, and the sensitivity to sub-PeV gamma rays.

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T. Kawashima, The ALPACA Collaboration. 2022-08-31. The ALPACA experiment: The project of the first sub-PeV gamma-ray observation in the southern sky. https://arxiv.org/abs/2208.14659

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