Measurement of the sign of the spectroscopic quadrupole moment for the 2(1)+ state in 70Se: no evidence for oblate shape.
Using a method whereby molecular and atomic ions are independently selected, an isobarically pure beam of 70Se ions was postaccelerated to an energy of 206 MeV using REX-ISOLDE. Coulomb-excitation yields for states in the beam and target nuclei were deduced by recording deexcitation gamma rays in the highly segmented MINIBALL gamma-ray spectrometer in coincidence with scattered particles in a silicon detector. At these energies, the Coulomb-excitation yield for the first 2+ state is expected to be strongly sensitive to the sign of the spectroscopic quadrupole moment through the nuclear reorientation effect. Experimental evidence is presented here for a prolate shape for the first 2+ state in 70Se, reopening the question over whether there are, as reported earlier, deformed oblate shapes near to the ground state in the light selenium isotopes.
Hurst
A M
AM
Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE, United Kingdom.
Butler
P A
PA
Jenkins
D G
DG
Delahaye
P
P
Wenander
F
F
Ames
F
F
Barton
C J
CJ
Behrens
T
T
Bürger
A
A
Cederkäll
J
J
Clément
E
E
Czosnyka
T
T
Davinson
T
T
de Angelis
G
G
Eberth
J
J
Ekström
A
A
Franchoo
S
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Georgiev
G
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Görgen
A
A
Herzberg
R-D
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Huyse
M
M
Ivanov
O
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Iwanicki
J
J
Jones
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GD
Kent
P
P
Köster
U
U
Kröll
T
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Krücken
R
R
Larsen
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AC
Nespolo
M
M
Pantea
M
M
Paul
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ES
Petri
M
M
Scheit
H
H
Sieber
T
T
Siem
S
S
Smith
J F
JF
Steer
A
A
Stefanescu
I
I
Syed
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Van de Walle
J
J
Van Duppen
P
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Wadsworth
R
R
Warr
N
N
Weisshaar
D
D
Zielińska
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