Speaker
Mr
george lowani zimba
(university of johannesburg)
Description
The N = 88 154Dy rare earth neutron rich nuclei offer an opportunity to study nuclear structure in the transitional region where the nuclear shape changes rapidly from vibrational to rotational motion. The question still remains whether at low spins the N=88 and 90 nuclei structure exhibits permanent octupole deformation [1] or aligned tidal wave octupole phonons [2]. The N = 88 isotones such as 154Dy88 have remarkable features; they are at a peak in the |M(E3)|2 transition strength of 01+ → 31- transitions for even-even nuclei as a function of neutron number [3]. This experimental evidence is consistent with the interpretation of an octupole vibration. The N = 88 isotones also have very strong E0 transitions from the band built on the 02+ states to the ground state bands [4,5].
The low spin states of 154Dy were studied with the AFRODITE spectrometer array equipped with 9 clover High Purity Germanium (HPGe) detectors at iThemba LABS, South Africa. The reaction 15564Gd91 (32He1, 4n) 15466Dy88 at 37.5MeV was used to populate these states. A first observation of enhanced E1 transitions in the transitional isotones 150Sm and 152Gd from the levels in the first excited 0+ band to the lowest negative parity band has been reported [3]. The results we report here are the first observation of enhanced E1 transitions from the low-lying negative parity band to the band built on the first excited 0+ state in 154Dy. These measurements on 154Dy extend the systematics on the relationship between the first excited positive parity pairing isomer band and the first excited negative parity band as the nuclear deformation decreases with increasing proton number.
Reference
[1] R. R. Chasman, Phys. Rev. Lett. 42, 630 (1979).
[2] S. Frauendorf, Phys. Rev. C77, 021304(R) (2008).
[3] R. H. Spear and W. N. Catford, Phys. Rev. C41, R1351 (1990).
[3] S. P. Bvumbi et al., Phys. Rev. C 87, 044333 (2013).
[4] A. Passoja et al., J. Phys. G12, 1047 (1986)
[5] J. L. Wood et al., Nucl. Phys. A651, 323 (1999)
Primary author
Mr
george lowani zimba
(university of johannesburg)
Co-authors
Dr
Elena Lawrie
(iThemba Laboratory for Accelerator Based Sciences)
Dr
John. F Sharpey-Schafer
(iThemba Laboratory for Accelerator Based Sciences)
Dr
Pete Jones
(iThemba Laboratory for Accelerator Based Sciences)
Mr
Siyabonga Majola
(University of Cape Town)
Dr
Tshepo Dinoko
(University of Western Cape)
Dr
paulus Masiteng
(university of johannesburg)
Dr
suzan bvumbi
(university of johannesburg)
