Change of primary cosmic radiation nuclear composition in the energy   range 10^{15} - 10^{17} eV
  The dependence E_h (N_e) of Extensive Air Shower (EAS) hadronic component energy flux on the number N_e of particles in EAS is investigated in the primary energy range of the order of 10^{15} - 10^{17} eV. The work was aimed at checking the existence of irregularities of E_h (N_e)/N_e behavior at these energies in several independent experiments. The investigation is carried out using large statistical material obtained at different configurations of experimental apparatus and under different triggering conditions. The existence of irregularities of E_h (N_e)/N_e behavior in the region Ne > 2*10^6 is confirmed. These irregularities have the character of sharp deeps and are located near the same values of N_e regardless of the experimental material and selection conditions used. So, at recent stage of research the existence of these irregularities of E_h (N_e)/N_e behavior in the range of N_e > 2*10^6 may be regarded as reliably established. This fact supports our earlier conclusion on the existence of primary cosmic radiation (PCR) nuclei spectra cutoff effect in the primary energy region 10^{15} - 10^{17} eV. 
T.T. Barnaveli (1), T.T. Barnaveli (jr)(1), A.P. Chubenko (2), N.A.   Eristavi (1), I.V. Khaldeeva (1), N.M. Nesterova (2), ...