Electron production in the lower ionosphere by a diffuse galactic X-ray background

The electron production rates in the lower ionosphere, due to galactic X-rays, are computed. It is shown that the contribution of photons of energies greater than 10 keV is relevant below 80 km. A non constant photoionization yield is introduced in the ionization rate calculations, proving that the constant value given by other authors underestimates the value of the total ion production. Using the spectrum considered more adequate, it is shown that at night the galactic X-ray contribution is not significant compared with the rate of ionization due to cosmic rays and scattered Lyman-α radiation.