Argonne Gas-filled Fragment Analyzer-AGFA Argonne National Laboratory

As the premier stable-beam user facility in the USA, ATLAS is currently being upgraded to provide high intensity (>1 pμA) stable beams. The combination of new highefficiency detectors and intense beams will move ATLAS to the forefront as a world research center for studying exotic nuclei, such as super-heavy nuclei, nuclei at or near the proton drip line, proton-rich nuclei near 100 Sn and neutron-rich nuclei important for the r-process. In order to take advantage of these new opportunities, we propose to construct a gas-filled separator, based on a new, innovative QvDm design, which combines the following properties: (a) high efficiency (e.g. 71% for evaporation residues produced in the 208 Pb( 48 Ca,2n) 254 No reaction), (b) small image size (~ 64 x 64 mm 2 ), which leads to improved γ-ray detection efficiency for isomericor radioactivedecay of the residues, and (c) the ability to accommodate Gammasphere, with an 80-cm flight path from the target to the first magnetic element Qv.