Prospects for Searching for Ultra-High Energy Gamma-Quanta at Russian Installations

The review is devoted to ultrahigh-energy gamma-ray astronomy, a branch of gamma-ray astronomy that studies photons with energies higher than 100 TeV. Gamma quanta of such energies can be generated in sources that accelerate protons and electrons to energies above 1 PeV. Such sources are commonly called PeVatrons, the study of which is important for understanding the origin of cosmic rays. The article briefly discusses possible galactic PeVatrons, research methods, setups, and results in the field of ultrahigh-energy gamma-ray astronomy. The second part of the article is devoted to the history, results and prospects of Russian installations in the region of ultrahigh energy gamma-ray astronomy.