Study of ²⁰⁷Tl₁₂₆ Produced in Deep-Inelastic Reactions

¹ Department of Physics, University of Surrey, Guildford, GU2 7XH, UK
² H. Niewodniczański Institute of Nuclear Physics, PL-31342 Kraków, Poland
³ Physics Division, Argonne National Laboratory, Argonne, IL 60439 USA
⁴ Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
⁵ Department of Physics, University of Massachusetts Lowell, Lowell, MA 01854, USA
⁶ Department of Nuclear Physics, Research School of Physics and Engineering Australian National University, Canberra, ACT 0200, Australia
⁷ GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
⁸ Nuclear Engineering Division, Argonne National Laboratory, Argonne, IL 60439, USA
⁹ National Physical Laboratory, Teddington, TW11 0LW, UK
¹⁰ School of Computing, Engineering and Mathematics, University of Brighton, Brighton, BN2 4GL, UK

^a e-mail: emma.wilson@surrey.ac.uk

Published online: 20 March 2014

Abstract

Deep-inelastic collisions of a ²⁰⁸Pb beam on a ²⁰⁸Pb target were performed using the ATLAS accelerator at Argonne National Laboratory. The Gammasphere detector array was used for the detection of prompt and delayed gamma-rays of the reaction products.²⁰⁷Tl is one proton away from the 208Pb doubly-magic nucleus. Its low-energy level structure is dominated by the single proton-hole states πs_1/2⁻¹, πd_3/2⁻¹ and πh_11/2⁻¹. The 11/2⁻ state is isomeric with T_1/2 = 1.33(11) s. The reaction partner of ²⁰⁷Tl is ²⁰⁹Bi, which has arelatively well established level scheme compared to ²⁰⁷Tl. Cross-coincidences between these two nuclei were used to confirm or establish levels above the 11/2⁻ isomeric state in ²⁰⁷Tl. These states are obtained via breaking of the neutron core. Angular correlation analysis was performed on known transitions in ²⁰⁸Pb, proving the applicability of this method for multipolarity assignment.