The Barcelona Raman LIDAR project and its prospects for the CTAO-North

Abstract The Cherenkov Telescope Array Observatory (CTAO) is a next-generation facility comprised of ground-based Imaging Atmospheric Cherenkov Telescopes (IACTs). The observatory, currently under construction, will include more than 70 telescopes at two locations: in the northern hemisphere, CTAO-North at the Observatorio del Roque de Los Muchachos (ORM), La Palma, Canary Islands, Spain, and in the southern hemisphere, CTAO-South at a site belonging to the European Southern Observatory (ESO), Cerro Paranal, Chile. IACTs indirectly detect high-energy cosmic photons in an energy range from tens of GeV to several hundreds of TeV by measuring Cherenkov light emitted by atmospheric showers of secondary particles, produced through interactions between incident photons and nuclei of atmospheric gasses in the upper layers. The size of the CTAO will improve the detection sensitivity in the designed energy range by about an order of magnitude with respect to present experiments and aim at improved energy and angular resolution, as well as greatly reduced systematic uncertainties. The key to achieving improvements in accuracy on the absolute energy and flux scales is the precise monitoring of the atmospheric properties for the Cherenkov light, which can be obtained with a specifically designed LIDAR. The Barcelona Raman LIDAR (BRL) prototype is the official CTAO-North Pathfinder and was deployed at ORM for extensive tests between February 2021 and May 2022. We report the BRL’s prospects for the CTAO-North, emphasizing the technical implementation and the preliminary data taken during its deployment period.