Mass separation of rare-earth elements by a high-temperature thermal ion source coupled with a He-jet system

Abstract By using a high-temperature thermal ion source coupled to a He-jet system, neutron-rich isotopes of rare-earth elements such as cerium, praseodymium, neodymium and promethium produced by the thermal-neutron fission of 235 U were ionized and successfully separated. The temperature dependence of the ionization efficiency has been measured and found to be explained qualitatively by the vapour pressure of the relevant element. The characteristic temperature dependence of the ionization efficiency can be utilized for Z -identification of several isobars of rare-earth elements. The heaviest isotopes of neodymium and promethium, 155 Nd and 156 Pm, have recently been identified.