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IN A SEARCH FOR TETRAHEDRAL SYMMETRIES IN 156Dy. S.N.T Majola † $, J F Sharpey-Schafer#*, R A Bark$, P Datta$, S P Bvumbi#, E A Georgieva Lawrie$, P Jones$, S M Mullins$,T Dinoko$#, D Negi$, L P Masiteng$, P Papka$‡, S Ntshangase†, O Shirinda$, Lee Riedinger and D. J Hartley Ӝ. - PowerPoint PPT Presentation
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IN A SEARCH FOR TETRAHEDRAL SYMMETRIES IN 156Dy
S.N.T Majola†$, J F Sharpey-Schafer#*, R A Bark$, P Datta$, S P Bvumbi#, E A Georgieva Lawrie$, P Jones$, S M Mullins$,T Dinoko$#, D Negi$, L P Masiteng$,
P Papka$‡, S Ntshangase†, O Shirinda$, Lee Riedinger and D. J HartleyӜ.
#University of Western Cape, Department of Physics, P/B X17, Bellville, ZA-7535 RSA
* University of Zululand, Department of Physics, P/B X1001, Kwa Dlangezwa, ZA-3886 RSA
$ IThemba Laboratory for Accelerator Based Sciences, PO Box 722, Somerset, ZA-7129 RSA
Ӝ University of Tennessee, Department of Physics, Knoxville, TN 37996-1200, USA
§ Faculty of Physics, St. Kliment Ohridski University of Sofia, Sofia 1164, Bulgaria.
† University of Cape Town, Department of Physics, Private Bag X3,Rondebosch,7701, RSA
‡ University of Stellenbosch, Department of Physics, Private Bag X1, Maitland, 7601 X3, RSA
13th September 2012
156Dy
N=90 Z=66
Charts of The Nuclides
- 156Dy is Localized in the transitional rare earth region - Has been studied extensively, especially at high spin - still poorly understood at low spin
Background and motivation-Recent Calculations by Dudek (THEORETICIAN)
Tetrahedral shape characterized by an α32
in the expansion of the nuclear surface:
00 ),(Y1R),(R
13th September 2012
Background and Motivation -160 mass region
Dudek Calculations for 156Dy (N=90)
13th September 2012
TetrahedralMinima
Background and Motivation- Possible Candidate for Tetrahedral in 156Dy
Odd spin- Tetra Candidate
13th September 2012
Masri et al., de Boer et al., Emling et al.,Riley et al., Caprio et al. and Morrison et al.
Background and Motivation-Previous studies
Negative parity sequence previously known as an octupole bands
Absence results from a much greater E1 rate to the ground band
The purpose of this study is learn which of these explanations is correct
13th September 2012
Odd spin- Tetra Candidate
Masri et al., de Boer et al., Emling et al.,Riley et al., Caprio et al. and Morrison et al.
Experimental Details
Analyzed data acquired using GAMMASPHERE (ANL, USA)
Produced by 148Nd(12C,4n)156Dy reaction; 65MeV – Fusion Evaporation Reaction
2.5 x 109 events
13th September 2012
Experimental Details -GAMMASPHERE Sphere at Argonne National
Laboratory
13th September 2012
Status of The Analysis (156Dy)- E2s
Tetrahedral candidate
Ground StateBand
12th September 2012
Masri et al., de Boer et al., Emling et al.,Riley et al., Caprio et al. and Morrison et al.
Tetrahedral candidate
148Nd (12C, 4n) 156Dy
Status of The Analysis (156Dy)- E2s
(5- → 3-) still missing!
Tetrahedral candidate
Ground StateBand
13th September 2012
Discussion-Systematic Comparison
13th September 2012
Discussion -Systematic Comparison
13th September 2012
Discussion- Band mixing Model
)()( 2/92/72/13 hfviv
6th September 2011
Spin 0 10 20
)()( 2/92/72/13 hfviv
Conclusion
(2+ → 0+) missing!
13th September 2012
β-band
Status of The Analysis (156Dy) (-ve parity bands)
GroundStateBand
Tetrahedral candidate
Masri et al., de Boer et al., Emling et al.,Riley et al., Caprio et al. and Morrison et al.
BandX
13th September 2012
Status of The Analysis (156Dy) (+ve parity bands)
Masri et al., de Boer et al., Emling et al.,Riley et al., Caprio et al. and Morrison et al.Ground
StateBand
β-band
13th September 2012
Status of The Analysis (156Dy) (Gamma Band bands extended)
OddGammaBand
OddGammaBandOdd
GammaBand
EvenGamma
Band
OddGamma
Band
OddGamma
Band148Nd (12C, 4n) 156Dy
124Sn (36S, 4n) 156Dy
S-Band GS-Band
13th September 2012
Status of The Analysis (156Dy) (Gamma Band bands)
156Dy
spin (h)
0 5 10 15 20 25 30
E-7
.7I(
I+1
)ke
V
0
400
800
1200
1600
2000
2400
gs bandodd gammaeven gammasbandgamma couplingbeta
N=90Odd
GammaBand
EvenGamma
Band
OddGamma
Band
OddGamma
Band148Nd (12C, 4n) 156Dy
124Sn (36S, 4n) 156Dy
S-Band GS-Band
13th September 2012
Status of The Analysis (156Dy) (Spin and parity - Unknown)
GroundStateBand
β-band
13th September 2012
