Some new trends in laser isotope separation in atomic vapours

New approaches to the methods of laser isotope separation are considered and realised which substantially extend the possibilities of the methods. To narrow down an absorption line and decrease parasitic absorption at transitions in isotope atoms that do not belong to an isotope being separated, two-photon excitation of atoms was used both in collinear and counterpropagating light beams. By using two-photon excitation in counterpropagating light beams, the weight amounts of Zn isotopes were separated under the conditions when the isotopic structure of a resonance transition was completely masked by the Doppler broadening. Two-photon excitation in collinear beams was used for efficient purification of lead from a rare ²¹⁰Pb isotope to obtain a low-radioactive lead. A detailed computer simulation of separation of isotopes of Zn, B, Pb, and Si using two-photon excitation was performed. An efficient method of isotope separation involving chemical reactions with selectively excited long-lived atoms was proposed and realised. The method offers some advantages over the conventional photoionisation method.