  We calculate the electron energy spectrum of ionization by a high energy
photon, accompanied by creation of electron-positron pair. The total cross
section of the process is also obtained. The asymptotics of the cross section
does not depend on the photon energies. At the photon energies exceeding a
certain value $\omega_0$ this appeares to to be the dominant mechanism of
formation of the ions. The dependence of $\omega_0$ on the value of nuclear
charge is obtained. Our results are consistent with experimental data.
