The Upper Limit on Isotropic Flux of Diffuse Gamma Rays with Energy Above 700 TeV as Measured by the Carpet-2 Air Shower Array

An experiment for measuring the flux of cosmic diffuse gamma rays with energies higher than 100 TeV (the Carpet-3 project) is under preparation at the Baksan Neutrino Observatory. The experiment suggests to increase areas of both the muon detector and the surface shower detectors. The experiment’s sensitivity to the showers initiated by primary gamma rays is estimated in this paper for different configurations of the array. In addition, preliminary estimates of the upper limit on diffuse gamma rays with energy above 700 TeV are presented. They are derived from experimental data of the Carpet-2 array (previous version of the experiment) for the net exposure of 9.2 years of observation.