The ALPACA detector is currently being constructed to study high-energy gamma-ray astronomy in the SubPeV region of the southern galactic sky.
The ALPACA consists of a ground-based air shower detector array(AS) and an underground muon detector array (MD) installed underground, and this experiment uses the muon intensity measured by MD to increase sensitivity to cosmic gamma rays.
This study evaluated the hadronic interaction model dependence in in the detection efficiency of gamma-ray-induced air showers using the ALPAQUITA configuration, which is the prototype of the ALPACA.
The model dependence on hadronic interactions is smaller than 3.6 % in the typical gamma-ray flux estimation performed by ALPAQUITA.
This is negligible compared with other uncertainties such as absolute energy scale uncertainty in the energy range from 6 to 300 TeV, which is dominated by the Monte Carlo statistics.
We also expect this small model dependence can be applied to ALPACA.