The interactions of beta particles with orbital electrons are most important. Coulomb
repulsion between beta particles and electrons frequently results in ionization. In the
ionization process, the beta particles lose an amount of energy equal to the kinetic energy of
the electron plus the energy used to free it from the atom. A beta particle may produce 50 to
150 ion pairs per centimeter of air before its kinetic energy is completely dissipated. The
characteristic X-rays are emitted, when the vacant internal electron orbits are refilled with
other electrons. Beta particles also cause excitation of external orbital electrons, which in turn
leads to the emission of ultraviolet photons.