Selective Photoionization of Odd-Mass Zirconium Isotope: Toward Application to Separation of Radioactive Waste

Isotope separation methods are crucial to numerous scientific and industrial processes; Nuclear power plants require fuels enriched in a select isotope and separate radioactive isotopes for disposal. The odd-mass Zirconium isotopes are among fission products that show radioactive. Separation of such high-level radioactive isotopes may make a pivotal contribution to a way to dispose of waste and recycle non-radiative isotopes. We employed a laser photoionization technique that provides an alternative approach using intermediate-state alignment for isotope-selective laser excitation of atoms, in which exploits the angular momentum selection rules for the absorption of polarized light. We have demonstrated that the ⁹¹Zr in the natural substance was selectively photoionized while the photoions of the even-mass isotopes were significantly suppressed by polarized, broadband pulsed lasers.  In our four-steps photoexcitation (J=2-1-1-0) scheme, high ionization efficiency with quite a high selectivity (⁹¹β >2400) has been achieved. Insights obtained and applications to advances in laser isotope separation will be presented and discussed.