Ion guide method for isotope separator

Abstract

A fundamentally new ISOL technique, the ion guide method for isotope separator has been developed. The method is based on thermalization of primary recoil ions from nuclear reactions or radioactive decays in helium and on their transfer by helium flow through a differential pumping system into the accelerating stage of an isotope separator. With this approach, separation times in the submillisecond region are achievable for both volatile and nonvolatile elements. Three main differences between the ion guide and conventional ion sources are emphasized: In the ion guide no ionizers are used, instead natural charge creation mechanisms related to nuclear reactions and radioactive decays are exploited. Secondly, the operation takes place at room temperature and thirdly the simple construction has no wearing components. These properties ensure continuously stable working conditions. The number of recoils per unit reaction cross-section stopped in helium seems to be almost constant in different reactions when equal operating conditions are used. The overall separation efficiencies measured for heavy nuclides induced in light ion reactions are up to 10%. The shortest lived activity identified in an on-line separation is the 182 μs isomeric state of ²⁰⁷Bi.