Ion-source development at the /sup 252/Cf ISOL facility

The ISOL system at the INEL utilizes the He-gas-jet techniques to transport fission products from /sup 252/Cf spontaneous-fission sources to the ion source of an electromagnetic mass separator. A long-lived, gas-jet-coupled ion source for production of rare-earth fission-product ion beams has been developed and implemented in this system. This paper describes the ion source, its operating parameters and its implementation in the search for new rare-earth element isotopes. New isotopes observed, with preliminary values of their half-lives in parentheses, are /sup 153/Pr(4.2 s). /sup 155/Nd(8.9 s). /sup 156/Nd(5.5 s), /sup 157/Pm(10.9 s). /sup 158/Pm(4.3 s) and /sup 162/Eu(11.0 s). Total separation efficiencies (based on the ratio of radionuclide activity collected at the focal plane of the mass separator to radionuclide activity generated by the /sup 252/Cf source) were estimated to be approximately 1% for /sup 154/Pm and 1% for /sup 158/Sm