Dipole strength distributions from HIGS Experiments

¹ Institut für Kernphysik, TU Darmstadt, Schlossgartenstr. 9, 64289 Darmstadt, Germany
² WNSL, Yale University, P.O. Box 208120, New Haven, CT 06520, USA
³ Department of Physics, University of Surrey, Guildford, GU2 7XH, UK
⁴ Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
⁵ Department of Physics & Astronomy, University of Kentucky, Lexington, KY 40506, USA
⁶ EMMI and Research Division, GSI, Planckstr. 1, 64291 Darmstadt, Germany
⁷ FIAS, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main, Germany
⁸ Triangle Universities Nuclear Laboratory, Durham, NC 27708, USA
⁹ Physics Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
¹⁰ Department of Chemistry, University of Kentucky, Lexington, KY 40506, USA
¹¹ School of Engineering, University of the West of Scotland, Paisley, PA1 2BE, UK
¹² SUPA, Scottish Universities Physics Alliance, Glasgow, G12 8QQ, UK

^a e-mail: vw@ikp.tu-darmstadt.de

Published online: 28 May 2015

Abstract

A series of photon scattering experiments has been performed on the double-beta decay partners ⁷⁶Ge and ⁷⁶Se, in order to investigate their dipole response up to the neutron separation threshold. Gamma-ray beams from bremsstrahlung at the S-DALINAC and from Compton-backscattering at HIGS have been used to measure absolute cross sections and parities of dipole excited states, respectively. The HIGS data allows for indirect measurement of averaged branching ratios, which leads to significant corrections in the observed excitation cross sections. Results are compared to statistical calculations, to test photon strength functions and the Axel-Brink hypothesis