Medium-spin states of the neutron-rich 87,89Br isotopes: configurations and shapes

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

Nyakó, B.M.^1 ; Timàr, J.^1 ; Csatlós, M.^1 ; Dombràdi, Zs^1 ; Krasznahorkay, A.^1 ; Kuti, I.^1 ; Sohler, D.^1 ; Tornyi, T.G.^1 ; Czerwiski, M.^2 ; Rzca-Urban, T.^2 ; Urban, W.^2 ; Bczyk, P.^2 ; Atanasova, L.^3 ; Balabanski, D.L.^4 ; Sieja, K.^5 ; Blanc, A.^6 ; Jentschel, M.^6 ; Köster, U.^6 ; Mutti, P.^6 ; Soldner, T.^6 ; De France, G.^7 ; Simpson, G.S.^8 ; Ur, C.A.^9

Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen

H-4026, Hungary^1

Faculty of Physics, University of Warsaw, ul. Pasteura 5, Warsaw

PL-02-093, Poland^2

Department of Med. Physics and Biophysics, Medical University - Sofia, Sofia

1431, Bulgaria^3

ELI-NP, Horia Hulubei National Institute for RandD in Physics and Nuclear Engineering IFIN-HH, Bucharest-Magurele

077125, Romania^4

Universitè de Strasbourg, IPHC, France

CNRS, UMR7178, Strasbourg

67037, France^5

Institut Laue-Langevin, Grenoble, France^6

GANIL, CEA/DSM CNRS/IN2P3, Bd Henri Becquerel, BP 55027, Caen Cedex 5

F-14076, France^7

LPSC, Universitè Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut National Polytechnique de Grenoble, Grenoble Cedex

F-38026, France^8

INFN, Legnaro, Italy^9

关键词: Cold neutron beams;    Ge detectors;    Ground-state spins;    Langevin;    Level schemes;    Shell models;    Spin levels;    Spin state;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/724/1/012051/pdf
DOI  :  10.1088/1742-6596/724/1/012051

来源: IOP

【 摘 要 】

Medium-spin excited states of the neutron-rich87Br and89Br nuclei were observed and studied for the first time. They were populated in fission of235U induced by the cold-neutron beam of the PF1B facility of the Institut Laue-Langevin, Grenoble. The measurement of γ radiation following fission has been performed using the EXILL array of Ge detectors. The observed level schemes were compared with results of large valence space shell model calculations. Both medium-spin level schemes consist of band-like structures, whihich can be understood as bands built on the πf5/2, πp3/2and πg9/2configurations. Both nuclei have 5/2-ground state spin-parity contrary to the odd-mass Br isotopes containing fewer neutrons, which have 3/2-ground state spin-parity. On the basis of the properties of the πg9/2decoupled bands the deformations of the87Br and89Br fit to the systematics of nuclei in the region.87Br is close to the vibrational limit, while89Br is more rotational.