Status of the GRAND project

TL;DR

GRAND is a large-scale radio array project aimed at detecting ultra-high-energy neutrinos, with prototype arrays validating its technology and paving the way for a 10,000-antenna observatory planned for 2030.

Contribution

This paper provides an overview of the GRAND project's current status, prototype performances, and future plans for a next-generation neutrino observatory.

Findings

Prototype arrays have successfully validated detection principles.

First cosmic ray detections have been achieved.

The project is progressing towards deploying a 10,000-antenna array by 2030.

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.