An ion guide for the production of a low energy ion beam of daughter products of α-emitters

A new ion guide has been modeled and tested for the production of a low energy (≈40 kV) ion beam of daughter products of alpha-emitting isotopes. The guide is designed to evacuate daughter recoils originating from the α-decay of a 233U source. The source is electroplated onto stainless steel strips and mounted along the inner walls of an ion guide chamber. A combination of electric fields and helium gas flow transport the ions through an exit hole for injection into a mass separator. Ion guide efficiencies for the extraction of 229Th+ (0.06%), 221Fr+ (6%) and 217At+ (6%) beams have been measured. A detailed study of the electric field and gas flow influence on the ion guide efficiency is described for two differing electric field configurations.