Christopher Ian Freigang, SUNY Stony Brook

Title: Design and Construction of an Ion Beam Transport System for Francium

Authors: C.I. Freigang, M.F. Ifferte, J.E. Simsarian, L.A. Orozco, G.D. Sprouse, W.Z. Zhao, M. Pearson, J.S. Grossman (SUNY Stony Brook)

Abstract: Atomic spectroscopy of radioactive francium has been performed in a magneto-optical trap located 1 m from the Fr production target.  The neutron flux from the target hampers working near the experiment.  We have now constructed and tested an electrostatic system to transport the Fr 12m from the target to a room where the experiment can be set up with unlimited access.  The 197Au production target is held at +10kV. When heated, Fr is released, accelerated, and then focused with a series of electrostatic optical elements.  These elements include Einzel Lenses, quadrupoles, and a 90o bender, all designed to fit in the standard 10cm diameter beam pipe.  The ion optics were first modeled in SIMION before design and construction began.  Stable Rb ions generated on the target by surface ionization, were used to test the system and optimize the optical elements. Fr was then produced, and a flux of 3.0x106 Fr/sec in the region of the trap was seen.  This resulted in a greater than 90% transmission efficiency. In the most recent tests, a 198Pt target and a  19F beam has been used to produce 211, 212Fr in addition to the 208, 209, 210Fr previously produced with 18,16O on Au.