Sensitivity to point-like sources of the ALTO atmospheric particle detector array, designed for $200\mathrm{G}\mathrm{e}\mathrm{V}$--$50\mathrm{T}\mathrm{e}\mathrm{V}$ $\gamma$-ray astronomy

In the context of atmospheric shower arrays designed for $\gamma$-ray astronomy and in the context of the ALTO project, we present: a study of the impact of heavier nuclei in the cosmic-ray background on the estimated $\gamma$-ray detection performance on the basis of dedicated Monte Carlo simulations, a method to calculate the sensitivity to a point-like source, and finally the required observation times to reach a firm detection on a list of known point-like sources.