Isotope selective excitation of Gd-155 and Gd-157 isotopes from D-9 degrees(2-6) states using broadband lasers

The feasibility of isotope enrichment of Gd-155 and Gd-157 isotopes using r elatively broadband lasers within the-tuning range of rhodamine-6G dye has been studied. A new set of photoionization schemes have been proposed for u sing in the industrial scale enrichment of these isotopes. These photoioniz ation schemes result in better photon economy compared to the photoionizati on schemes reported earlier. The enriched isotopic mixture results in a 50% increase in the neutron absorption cross-section and a 70% reduction in th e residual neutron absorption. The degree of enrichment of the odd isotopes is adequate for using the enriched mixture as an efficient burnable poison , The effect of linewidth of the excitation laser and Doppler width of the atom source on the degree of enrichment have been theoretically evaluated a nd experimentally verified. The computed selectivities were in good agreeme nt with the experimental results. (C) 1999 Elsevier Science B.V. All rights reserved.