FLUKA-Geant4 comparison for the muon flux experiment in the H4 beamline

The FLUKA - Geant4 comparison for the the muon flux experiment is reported. The experiment was performed in 2018 on the H4 400 GeV/c proton beamline to measure the muon flux emanating from a SHiP replica target. Good agreement between the two Monte Carlo simulations was found, in the low momentum and low transverse momentum range the agreement is at the level of 20%, while in the tails the disagreement is at maximum of a factor ∼3. These results suggest to reduce the safety factor for future BDF/SHiP facility radiation calculations from 5 (old recommended value) to 3 (new value).