Search for Isovector Valence-Shell Excitations in ¹⁴⁰Nd and ¹⁴²Sm via Coulomb excitation reactions of radioactive ion beams

¹ Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany
² Faculty of Physics, St. Kliment Ohridski University of Sofia, BG-1164 Sofia, Bulgaria
³ CERN, CH-1211 Genève, Switzerland
⁴ Institut für Kernphysik, Universität zu Köln, D-50937 Cologne, Germany
⁵ Department of Physics, Lund University, S-22100 Lund, Sweden
⁶ Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40351 Jyväskylä, Finland
⁷ University of the West of Scotland, High Street, Paisley PA1 2BE, United Kingdom
⁸ Department of Physics and Astronomy, University of the Western Cape, 7535 Bellville, South Africa
⁹ iThemba LABS, National Research Foundation, PO Box 722, 7129 Somerset West, South Africa
¹⁰ National Institute for Physics and Nuclear Engineering, R-77125 Bucharest-Magurele, Romania
¹¹ Instituut voor Kern- en Strahlingsfysica, K.U. Leuven, B-3001 Leuven, Belgium

^* e-mail: rkern@ikp.tu-darmstadt.de

Published online: 14 November 2018

Abstract

Projectile Coulomb excitation experiments were performed at HIE-ISOLDE at CERN with the radioactive ion beams of ¹⁴⁰Nd and ¹⁴²Sm. Ions with an energy of 4:62 MeV/A were impinging on a 1.45 mg/cm² thick ²⁰⁸Pb target. The γ-rays depopulating the Coulomb-excited states were recorded by the HPGe-array MINIBALL and scattered particles were detected by a double-sided silicon strip detector. Experimental intensities were used for the determination of electromagnetic transition matrix elements. A preliminary result of the B(M1; 2⁺₃ → 2⁺₁) of ¹⁴⁰Nd and an upper limit for the case of ¹⁴²Sm are revealing the main fragments of the proton-neutron mixed-symmetry 2⁺_1;ms states.