Production of radioactive beams of francium

We describe the production of francium beams from the fusion-evaporation reaction 197 Au(18O; kn) 215-k Fr generated by a ~100 MeV 18O6+ beam on a thick gold target. The physics of the production process is discussed, together with estimates of expected production rates. The production target is heated to ~1200 K and kept at a potential of +3 kV to enhance Fr diffusion and surface desorption, and to accelerate surface-ionized ions. Details are given on its design and construction. The performance of the target is measured as a function of primary beam energy and flux, target temperature and extraction voltage. Average production rates are 0.7 x 10^6 ions/s for 210 Fr with a primary beam flux of 10^12 particles/s, with peaks of 2 x 10^6 ions/s. From these measurements, information on the efficiency of the release processes is inferred.