Status of the GRAND project (2507.07260v1)

Abstract: GRAND (the Giant Radio Array for Neutrino Detection) is a proposed next-generation observatory targetting primarily the detection of ultra-high-energy neutrinos, with energies exceeding about 100 PeV. GRAND is envisioned as a collection of large-scale ground arrays of self-triggered radio antennas that target the radio emission from extensive air showers initiated by UHE particles. Three prototype arrays are presently in operation: GRANDProto300 in China, with 65 units running since end of 2024, GRAND@Auger in Argentina with 10 units deployed on the site of the Pierre Auger Observatory, and GRAND@Nan\c{c}ay in France, a 4-unit setup installed at the Nan\c{c}ay radio-observatory and used for test purposes. The main objective of the GRAND prototype phase is to validate the detection principle and technology of GRAND, in preparation for its next phase, GRAND10k. GRAND10k will consist of two arrays of 10'000 antennas each, covering both the Northern and Southern hemispheres, to be deployed from 2030 on. Here we give an overview of the GRAND concept, its science goals, the status of the prototypes, their performances and first detection of cosmic rays, and the technical perspective they open for the future.