Résumé
Very-high-energy (VHE) interaction between cosmic-ray proton and nuclei in the atmosphere is still not perfectly understood and efforts to improve interaction models used in simulations are ongoing, with feedback from various collider and air shower experiments. Imaging Atmospheric Cherenkov Telescopes (IACTs) are indirect VHE gamma-ray detectors on the ground and cosmic-ray proton is a major background to gamma-ray measurements in these systems. Rejection power of background protons determines most part of the gamma-ray sensitivity curve of IACTs. As for an IACT system in design phase, simulated proton events are used to estimate the residual background level. We investigated the influence of the uncertainty in the current hadronic interaction models on the estimated gamma-ray sensitivity of Cherenkov Telescope Array, using several interaction models available in CORSIKA.