Francium sources at LNL: design and performance

A facility for the production of radioactive francium is operating at the laboratories of the Istituto Nazionale di Fisica Nucleare (INFN) in Legnaro, Italy. The goal is to collect a cold sample of radioactive atoms in a magneto-optical trap for studies in atomic, nuclear, and particle physics. Production of francium is achieved via the fusion-evaporation reaction Au197 (O18, kn)215-k Fr generated by a ∼100-MeV O 6+ 18 beam on a thick gold target. The production target is heated to ∼1200 K and kept at a potential of +3 kV to enhance Fr diffusion and surface desorption. Average production rates are 0.7× 106 ionss for Fr210 with a primary beam flux of 1012 particless, with peaks of 2× 106 ionss. Details are given on the design and construction of the production targets and on the measurements that characterize their performance. © 2006 American Institute of Physics.