Search for diffuse cosmic gamma rays of energy Eγ > 100 TeV with the Carpet-3 air shower array

Abstract

An experiment for measuring the flux of gamma rays of cosmic origin with energy above 100 TeV is currently being prepared at the Baksan Neutrino Observatory (the Carpet-3 experiment). The experiment performance will be accomplished after radical modernization of the existing array by substantially increasing areas of both the muon detector and ground level shower array. In this work some results of calculations of efficiency of the experiment for showers from primary gamma rays are presented for different configurations of the array. It is demonstrated that by increasing the muon detector area up to 615 m² (the maximum possible value) one can reach with Carpet-3 the world-best sensitivity to 100 TeV gamma rays. The preliminary values of upper limits on the flux of cosmic diffuse gamma rays with energy higher than 1.3 PeV are also presented, derived from experimental data of the Carpet-2 shower array for a net exposure time of 9.2 years.