The Surface Array of IceCube-Gen2*

IceCube-Gen2, the next generation extension of the IceCube Neutrino Observatory at the South Pole, will feature a Surface Array on top of the enlarged Optical Array deep in the ice and also an even larger Radio Array for neutrino astronomy at the highest energies. The Surface Array will cover the footprint of the Optical Array in a similar way as IceTop covers the surface above IceCube’s current cubic-kilometer in-ice array, but being an order of magnitude larger in size and thus extending to higher energies. Detecting cosmic-ray air showers, the surface array will support neutrino astronomy by providing a veto for downgoing events and by measuring atmospheric backgrounds more accurately. Furthermore, IceCube-Gen2 will constitute a unique laboratory for the particle physics in cosmic-ray air showers because of the combination of a surface array that measures the electromagnetic shower particles and low-energy muons and a deep array that measures TeV to PeV muons produced in the same shower. In addition to the larger size, several improvements are made to the detector design compared to IceTop, e.g., the new surface detectors will be elevated to avoid snow coverage. Most importantly, a combination of scintillation detectors and radio antennas will increase the measurement accuracy for the cosmic-ray air showers detected by the surface array making IceCube-Gen2 the most accurate cosmic-ray detector for the energy range of the Galactic-to-extragalactic transition between around 100 PeV and a few EeV. Beyond the astrophysics of the most energetic Galactic cosmic rays, also important particle physics questions will be targeted, such as the cosmic-ray muon puzzle or the production of prompt leptons at PeV energies.