SELECTIVITY OF PHOTOION EXTRACTION FOR ISOTOPES OF RARE-EARTH ELEMENTS

An analysis of selectivity of three-stage photoionization for isotopes of rare-earth atoms with (1 - 2)-GHz isotopic shifts in the absence of polarization effects is performed. Because of field broadening, a sufficiently high selectivity eta greater-than-or-equal-to 100 is achieved only for low average laser intensities I less-than-or-equal-to 10 mW/cm2. The extraction of ions produced in photoionization of atoms by an electric field is investigated. The dependence of the selectivity on ion and gas densities, as well as on parameters of the external electric field, is calculated.