Imaging atmospheric Cherenkov telescopes (IACTs) are ground-based indirect detectors for cosmic gamma rays with energies above tens of GeV. The major backgrounds for gamma-ray observations in IACTs are cosmic-ray charged particles. The capability to reject these backgrounds is the most important factor determining the gamma-ray sensitivity of IACT systems. Monte Carlo simulations are used to estimate the residual background rates and sensitivity of the systems during the design and construction phase. Uncertainties in the modeling of high-energy hadronic interactions of cosmic rays with nuclei in the air propagate into the estimates of residual background rates and subsequently into the estimated instrument sensitivity. We investigate the influence of the difference in the current hadronic interaction models on the estimated gamma-ray sensitivity of the Cherenkov Telescope Array using four interaction models (QGSJET-II-03, QGSJET-II-04, EPOS-LHC, and SIBYLL2.3c) implemented in the air shower simulation tool CORSIKA. Variations in background rates of up to a factor 2 with respect to QGSJET-II-03 are observed between the models, mainly due to differences in the π ⁰ production spectrum. These lead to ∼30% differences in the estimated gamma-ray sensitivity in the 1–30 TeV region, assuming a 50 h observation of a gamma-ray point-like source. The presented results also show that IACTs have a significant capability in the verification of hadronic interaction models.

成像大气切伦科夫望远镜 (IACT) 是用于能量高于数十 GeV 的宇宙伽马射线的地面间接探测器。IACT 中伽马射线观测的主要背景是宇宙射线带电粒子。抑制这些背景的能力是决定 IACT 系统伽马射线灵敏度的最重要因素。Monte Carlo 模拟用于在设计和施工阶段估计系统的残留背景率和灵敏度。宇宙射线与空气中原子核的高能强子相互作用建模中的不确定性传播到剩余背景率的估计中，然后传播到估计的仪器灵敏度中。我们使用四种相互作用模型（QGSJET-II-03、QGSJET-II-04、EPOS-LHC 和 SIBYLL2.3c）研究当前强子相互作用模型的差异对切伦科夫望远镜阵列估计伽马射线灵敏度的影响) 在风淋模拟工具 CORSIKA 中实现。在模型之间观察到 QGSJET-II-03 的背景速率变化高达 2 倍，主要是由于π ⁰生产光谱。假设对伽马射线点状源进行了 50 小时的观察，这些会导致 1-30 TeV 区域内估计的伽马射线灵敏度存在约 30% 的差异。所呈现的结果还表明，IACT 在验证强子相互作用模型方面具有显着的能力。