The 2nd International African Symposium on Exotic Nuclei IASEN2024

First observation of rotational bands in the nucleus 231U

Not scheduled

20m

Krystal Beach Hotel (Cape Town)

Oral

Speaker

David G. Roux (Rhodes University)

Description

APS/123-QED

D.G. Roux
Rhodes University, Department of Physics and Electronics, Grahamstown 6140, South Africa.
S.S. Ntshangase
University of Zululand, Department of Physics, Private Bag X1001, KwaDlangezwa 3886, South Africa.
R.A. Bark, E.A. Gueorguieva-Lawrie, T.S. Dinoko, P. Jones, J.J. Lawrie, L.P. Masiteng, and O. Shirinda
iThemba LABS, National Research Foundation, P. O. Box 722, Somerset West 7129, South Africa.
J.L. Easton, B.V. Kheswa, N.A. Khumalo, S.P. Noncela, and J.F. Sharpey-Schafer
University of the Western Cape, Department of Physics, Private Bag X17, Bellville 7535, South Africa.
S.N.T. Majola
Department of Physics, University of Johannesburg,
P. O. Box 524, Auckland Park 2006, South Africa. and
iThemba LABS, National Research Foundation, P. O. Box 722, Somerset West 7129, South Africa.
D. Negi
iThemba LABS, National Research Foundation, P. O. Box 722, Somerset West 7129, South Africa. and
UM-DAE Centre for Excellence in Basic Sciences, Kalina, Mumbai 400098, India.
P.C. Uwitonze
Rhodes University, Department of Physics and Electronics, Grahamstown 6140, South Africa. and
University of Rwanda, Department of Mathematics,
Sciences and Physical Education, 50 Rwamagana, Rwanda.
(Dated: November 20, 2024)
The
-ray spectroscopy of uranium nuclei far from stability is compromised by large ?ssion cross
sections and competition from electron conversion. However, by using a recoil detector to discrimi-
nate against the ?ssion background, together with the afrodite
-ray spectometer array, we have
observed the ?rst rotational bands in 231U, to date the lightest odd uranium nucleus shown to exhibit
collective structure. Excited states were populated in the 232Th(?,5n) reaction at a beam energy
of 52 MeV. The data analysis revealed three rotational bands, interpreted as the ground-state band
?[633]5=2+, yrast band ?[752]5=2􀀀, and an excited band ?[631]3=2+. These con?guration assign-
ments are supported by Cranked Shell Model calculations and the electromagnetic properties of the
bands. The excitation energy of the ?[752]5=2􀀀 band head is suggested to be 113.0 keV.
PACS numbers: 21.10.-k,21.10.Re, 23.20.Lv, 27.70.+q