  As a result of absorption of X-ray quantum in a semiconductor, the generation
of electron-hole pairs takes place in a small volume (diameter < 0.5 mkm).
Their surplus energy is lost due to the scattering on phonons of the crystal
lattice. Spatial distribution of the charge carriers makes the form of current
pulse on electrodes of the crystal complicated when an external electric field
is applied. We present a logical chart of construction of basic kinetic model
of X-ray conductivity in semiconductors that uses the successive in time
calculation of the spatial distribution of free charge arriers and the
diffusive-drift model of motion of free carriers in a solid. The basic form of
current pulse in an external circle was obtained in the analytical kind for the
case of an ideal semiconductor, e.g. that does not contain deep traps and
recombination centers, as well as for the case of a crystal with dominant
shallow or deep traps of electrons and holes.
