An Ion Guide for the Production of a Low Energy Ion Beam of Daughter   Products of $\alpha$-Emitters
  A new ion guide has been modeled and tested for the production of a low energy ($\approx$ 40 kV) ion beam of daughter products of alpha-emitting isotopes. The guide is designed to evacuate daughter recoils originating from the $\alpha$-decay of a $^{233}$U 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 $^{229}$Th$^{+}$ (0.06%), $^{221}$Fr$^{+}$ (6%), and $^{217}$At$^{+}$ (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. 
B. Tordoff, T. Eronen, V.V. Elomaa, S. Gulick, U. Hager, P. Karvonen,   T. Kessler, J. Lee, I. Moore, A. Popov, S. Rahaman, ...