First observation of the competitive double-gamma (γγ/γ) decay process

21st International School on Nuclear Physics and Applications & International Symposium on Exotic Nuclei

Pietralla, N.^1 ; Walz, C.^1,3 ; Scheit, H.^1 ; Aumann, T.^1 ; Lefol, R.^1,2 ; Ponomarev, V Yu^1

Institut für Kernphysik, Technische Universität Darmstadt, Darmstadt

D-64289, Germany^1

Department of Physics, University of Saskatchewan, Saskatoon

S7N5E2, Canada^2

Bosch AG, Reutlingen, Germany^3

关键词: Angular correlations;    Decay mode;    Decay process;    Energy distributions;    Gamma quanta;    Gammagamma;    Quasi particles;    Second orders;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/724/1/012039/pdf
DOI  :  10.1088/1742-6596/724/1/012039

来源: IOP

【 摘 要 】

First observation of the competitive double-γ decay process is presented. It is a second-order electromagnetic decay mode. The 662-keV transition from the 11/2-isomer of137Ba to its ground state proceeds at a fraction of 2 x 10-6by simultaneous emission of two γ quanta instead of one. The angular correlation and energy distribution of coincident γ quanta are reproduced by a dominant M2-E2 and a minor E3-M1 contribution to the double-γ decay branch. The data are well accounted for by a calculation in the Quasiparticle Phonon Model.