Production of radioactive beams of francium

We describe the production of francium beams from the fusion-evaporation reaction generated by a MeV 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 and kept at a potential of 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 for 210Fr with a primary beam flux of , with peaks of . From these measurements, information on the efficiency of the release processes is inferred.