Dependence of the atmospheric muon rate on the sea water depth with first KM3NeT data

The first detection units of the KM3NeT/ORCA and KM3NeT/ ARCAneutrino telescopes have been deployed at the French and Italian sites in the Mediterranean Sea. The first collected data have been crucial to assess the detector performance and to establish the calibration procedures. The low-level data streams of the deployed ARCAand ORCA detection units, containing raw information on hits in coincidencebetween PMTs for each Digital Optical Module, have been analysed. The study of coincidencerates has been exploited to evaluate the dependence of the atmospheric muon rate as a function of the sea depth, which is found to be in good agreement with model predictions.