Constraints on the Number Density of Evaporating Primordial Black Holes   for the Chromospheric Evaporation Models
  Cosmic gamma-ray bursts with primary-photon energies > 10 GeV are sought in the data from the Andyrchy array obtained in the mode of detection of a single cosmic-ray component during a net observation period of 2005.4 d. The distribution of fluctuations of the detector counting rate agrees with the expected cosmic-ray background, the only exception being an event with a deviation of 7.9 sigma. Constraints on the number density of evaporating primordial black holes in a local region of the Galaxy are obtained for the chromospheric evaporation models. 
V. B. Petkov, E. V. Bugaev, P. A. Klimai, D. V. Smirnov