Nuclear Excitation by Electron Transition and Its Application to Uranium 235 Separation

Abstract

A new mechanism for nuclear excitation is studied theoretically by considering the de-excitation of electronic states of atom. When an electron of inner shells is kicked off by the bombarded electron or X ray, an electron of the adjacent shells immediately jumps into the vacancy. The energy corresponding to the difference of the binding energies for these two shells, E 1-E 2, is usually carried away by the emitted characteristic X ray or the Auger electron which is ionized from an outer shell. There is, however, another possibility of this energy release by exciting a nuclear state. That is, the nuclear ground state is excited to the higher energy level by receiving the excess energy of the electronic state by means of electromagnetic interactions between nucleus and electrons. A theory is made for this process, and it is found that the probability of this process is extremely small in most of the cases, but it will be appreciable, if the interaction energy is approximately equal to the energy mismatch EN-CE1-E2), where EN is the nuclear excitation energy. An example of 28; U is discussed in connection with a possible separation of 2a;u from uranium isotopes. §