-
J. F. Smith,
L. J. Angus,
E. S. Paul,
C. J. Chiara,
M. P. Carpenter,
H. J. Chantler,
P. T. W. Choy,
C. N. Davids,
M. Devlin,
D. B. Fossan,
S. J. Freeman,
R. V. F. Janssens,
N. S. Kelsall,
T. Koike, D. R. LaFosse,
D. G. Sarantites,
D. Seweryniak,
K. Starosta,
R. Wadsworth,
A. N. Wilson
[show abstract]
[hide abstract]
ABSTRACT: Excited states have been identified in the very neutron-deficient Z=58 nucleus 123Ce. This is the most neutron-deficient odd-A cerium isotope in which excited states have been identified. The states have been unambiguously assigned to 123Ce by detecting de-excitation γ rays in coincidence with evaporated charged particles and neutrons. Three rotational bands, each consisting of at least eight E2 transitions, have been observed. The bands have tentatively been assigned to be based on neutrons in g7/2 and h11/2 orbitals. Two of the bands have been assigned to be signature partners, although no interband transitions have been observed. The aligned angular momenta of the bands have been studied in comparison with neighboring nuclei and with the results of Woods-Saxon cranking calculations. Observation of the deformation-dependent π(h11/2)2 quasiparticle alignment at 0.36 MeV/ℏ in each of the bands suggests a quadrupole deformation of β2≃0.3, in good agreement with theoretical predictions for the suggested possible configuration assignments.
Physical Review C 09/2012; 86(3):034303. · 3.31 Impact Factor
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E. S. Paul,
A. O. Evans,
A. J. Boston,
C. J. Chiara,
M. Devlin,
D. B. Fossan,
S. J. Freeman, D. R. LaFosse,
G. J. Lane,
M. J. Leddy,
I. Y. Lee,
A. O. Macchiavelli,
P. J. Nolan,
D. G. Sarantites,
J. M. Sears,
A. T. Semple,
J. F. Smith,
K. Starosta,
A. V. Afanasjev,
I. Ragnarsson
[show abstract]
[hide abstract]
ABSTRACT: High-spin states have been populated in 52110Te via 58Ni(58Ni,α2pγ) reactions at 240 and 250 MeV. The Gammasphere γ-ray spectrometer was used in conjunction with the Microball charged-particle detector. The high-spin (I>30) collective level scheme of 110Te, up to ~45ℏ, is discussed in this paper. Four new decoupled (ΔI=2) high-spin structures have been observed for the first time, together with two strongly coupled (ΔI=1) bands. These bands all show the characteristics of smooth band termination, and are discussed within the framework of the cranked Nilsson-Strutinsky approach.
Physical Review C 09/2007; 76(3). · 3.31 Impact Factor
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E. S. Paul,
A. J. Boston,
C. J. Chiara,
M. Devlin,
D. B. Fossan,
S. J. Freeman, D. R. LaFosse,
G. J. Lane,
M. J. Leddy,
I. Y. Lee,
A. O. Macchiavelli,
P. J. Nolan,
D. G. Sarantites,
J. M. Sears,
A. T. Semple,
J. F. Smith,
K. Starosta
[show abstract]
[hide abstract]
ABSTRACT: Excited states have been populated in 52110Te via the 58Ni(58Ni,α2pγ) reaction at 250 MeV. The Gammasphere γ-ray spectrometer was augmented with ancillary detectors for charged-particle and neutron detection in order to provide clean channel selection. The known level scheme of 110Te has been greatly expanded with the addition of many new structures. Above spin 8+, negative-parity structures become yrast. The level scheme of 110Te below 30ℏ is discussed in this paper, including possible evidence for octupole correlations inferred from strong B(E1) strengths.
Physical Review C 09/2007; 76(3). · 3.31 Impact Factor
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C. J. Chiara,
M. Devlin,
E. Ideguchi, D. R. LaFosse,
F. Lerma,
W. Reviol,
S. K. Ryu,
D. G. Sarantites,
O. L. Pechenaya,
C. Baktash, [......],
T. Lauritsen,
C. J. Lister,
P. Reiter,
D. Seweryniak,
P. Fallon,
A. Görgen,
A. O. Macchiavelli,
D. Rudolph,
G. Stoitcheva,
W. E. Ormand
[show abstract]
[hide abstract]
ABSTRACT: An experimental study of the lower fp-shell nuclei 42,43Sc was performed via αpn and αp evaporation, respectively, from 20Ne + 28Si and 24Mg + 24Mg fusion-evaporation reactions. The experiments were conducted with the Gammasphere and Microball detector arrays. The level schemes of both nuclei have been extended considerably. Terminating states associated with the f7/2n and d3/2-1f7/2n+1 configurations were identified in each nuclide and incorporated into detailed comparisons with neighboring nuclei and with shell model calculations. The energy differences between the terminating states provide a test of the sd-fp cross-shell interactions in these calculations.
Physical Review C 05/2007; 75(5):054395. · 3.31 Impact Factor
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E. S. Paul,
K. Starosta,
A. O. Evans,
A. J. Boston,
H. J. Chantler,
C. J. Chiara,
M. Devlin,
A. M. Fletcher,
D. B. Fossan, D. R. LaFosse, [......],
I. Y. Lee,
A. O. Macchiavelli,
P. J. Nolan,
D. G. Sarantites,
J. M. Sears,
A. T. Semple,
J. F. Smith,
C. Vaman,
A. V. Afanasjev,
I. Ragnarsson
[show abstract]
[hide abstract]
ABSTRACT: The Gammasphere spectrometer, in conjunction with the Microball charged-particle array, was used to investigate high-spin states in 112Te via 58Ni(58Ni, 4pγ) reactions at 240 and 250 MeV. Several smooth terminating bands were established, and lifetime measurements were performed for the strongest one using the Doppler-shift attenuation method. Results obtained in the spin range 18-32ℏ yield a transition quadrupole moment of 4.0±0.5eb, which corresponds to a quadrupole deformation ɛ2=0.26±0.03; this value is significantly larger than the ground-state deformation of tellurium isotopes. It was also possible to extract a transition quadrupole moment for the yrast band in 114Xe, produced via the 58Ni (58Ni, 2pγ) reaction. A value of 3.0±0.5eb was found in the spin range 16-24ℏ, which corresponds to a quadrupole deformation ɛ2=0.19±0.03. Cranked Nilsson-Strutinsky calculations are used to interpret the results.
Physical Review C 01/2007; 75(1). · 3.31 Impact Factor
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J. F. Smith,
C. J. Chiara,
M. P. Carpenter,
C. N. Davids,
M. Devlin,
D. B. Fossan,
S. J. Freeman,
R. V. F. Janssens, D. R. LaFosse,
D. G. Sarantites,
D. Seweryniak,
K. Starosta,
R. Wadsworth,
A. N. Wilson,
R. Wyss
[show abstract]
[hide abstract]
ABSTRACT: Excited states have been observed for the first time in the very neutron-deficient, odd-odd nucleus, 55116Cs61. The assignment to 116Cs has been made by the detection of γ rays in coincidence with evaporated charged particles and with evaporation residues. The observed states form a rotational band which has been assigned to the ν(h11/2) ⊗ π(h11/2) configuration. Tentative spin assignments have been made on the basis of systematic comparisons with neighboring cesium isotopes. A low-spin signature inversion is observed in the band at a rotational frequency of about 0.23 MeV/ℏ. The observed signature inversions in the odd-odd 116-126Cs isotopes have been compared with the results of extended total Routhian surface calculations, in which signature inversion arises as a consequence of quadrupole-pairing correlations and triaxial deformation. As previously shown for some of the odd-odd A≃120 isotopes, the calculations reproduce the signature inversions reasonably well.
Physical Review C 09/2006; 74(3). · 3.31 Impact Factor
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A O Evans,
E S Paul,
A J Boston,
H J Chantler,
C J Chiara,
M Devlin,
A M Fletcher,
D B Fossan, D R LaFosse,
G J Lane, [......],
A O Macchiavelli,
P J Nolan,
D G Sarantites,
J M Sears,
A T Semple,
J F Smith,
K Starosta,
C Vaman,
I Ragnarsson,
A V Afanasjev
[show abstract]
[hide abstract]
ABSTRACT: A lifetime analysis using the Doppler-shift attenuation method has been performed on the Tellurium isotopes Te-110,Te-112. The experiment was performed using the Gammasphere array in conjunction with the MICROBALL charged-particle detector. Three strongly coupled bands were previously established in Te-110,Te-112 which were observed up to unusually high spins. In the current experiment, it has been possible to extract lifetime measurements using a Doppler broadened lineshape analysis on one of the Delta I = 1 band structures in Te-110. In contrast to similar Delta I = 1 structures in other nuclei in this mass region, the extracted B(M1) values did not rapidly decrease with increasing angular momentum. Instead, the strongly coupled band in Te-110 represents a deformed 1p-1h structure, rather than a weakly deformed structure showing the shears mechanism.
Physica Scripta 07/2006; T125:192-193. · 1.20 Impact Factor
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A.O. Evans,
E.S. Paul,
A.J. Boston,
H.J. Chantler,
C.J. Chiara,
M. Devlin,
A.M. Fletcher,
D.B. Fossan, D.R. LaFosse,
G.J. Lane, [......],
A.O. Macchiavelli,
P.J. Nolan,
D.G. Sarantites,
J.M. Sears,
A.T. Semple,
J.F. Smith,
K. Starosta,
C. Vaman,
A.V. Afanasjev,
I. Ragnarsson
[show abstract]
[hide abstract]
ABSTRACT: Three strongly coupled sequences have been established in 110,112Te up to high spins. They are interpreted in terms of deformed structures built on proton 1-particle–1-hole excitations that reach termination at I∼40ℏ. This is the first observation of smooth terminating dipole structures in this mass region. Lifetime measurements have allowed the extraction of experimental B(M1;I→I−1) and B(E2;I→I−2) reduced transition rates for one of the dipole bands in 110Te. The results support the deformed interpretation.
Physics Letters B 03/2006; 636(1):25-30. · 3.95 Impact Factor
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J F Smith,
C J Chiara,
M P Carpenter,
C N Davids,
M Devlin,
D B Fossan,
S J Freeman,
R V F Janssens, D R LaFosse,
D G Sarantites,
D Seweryniak,
K Starosta,
R Wadsworth,
A N Wilson,
R Wyss
Physical Review C 01/2006; 74:034310. · 3.31 Impact Factor
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S. Naguleswaran,
R. S. Chakrawarthy,
U. Garg,
K. L. Lamkin,
G. Smith,
J. C. Walpe,
A. Galindo-Uribarri,
V. P. Janzen,
D. C. Radford,
R. Kaczarowski,
D. B. Fossan, D. R. Lafosse,
P. Vaska,
Ch. Droste,
T. Morek,
S. Pilotte,
J. DeGraaf,
T. Drake,
R. Wyss
[show abstract]
[hide abstract]
ABSTRACT: Excited states in 113In were populated via the reactions 100Mo(18O,p4n)113In and 110Pd(7Li,4n)113In. The two known ΔJ=2 intruder bands, based on the πg7/2⊗d5/2 and πh11/2 orbitals, have been extended by 8ℏ to spins (49/2+)ℏ and (55/2-)ℏ, respectively. The previous finding of three sequences of ΔJ=1 γ-ray transitions has been confirmed. A self-consistent cranked shell-model calculation gives a good description of the contrasting alignment patterns of the two ΔJ=2 intruder bands. The intruder bands, the known sequences of M1 transitions, and spherical levels together represent a coexistence of three different excitation modes in this nucleus.
Phys. Rev. C. 10/2005; 72(4).
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S Naguleswaran,
R S Chakrawarthy,
U Garg,
K L Lamkin,
G Smith,
J C Walpe,
A Galindo-Uribarri,
V P Janzen,
D C Radford,
R Kaczarowski,
D B Fossan, D R Lafosse,
P Vaska,
Ch. Droste,
T Morek,
S Pilotte,
J DeGraaf,
T Drake,
R Wyss
Phys.Rev. C. 01/2005; 72:044304.
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J. F. Smith,
V. Medina-Chico,
C. J. Chiara,
M. P. Carpenter,
C. N. Davids,
M. Devlin,
J. L. Durell,
D. B. Fossan,
S. J. Freeman,
R. V. F. Janssens, D. R. LaFosse,
M. J. Leddy,
P. Reiter,
D. G. Sarantites,
D. Seweryniak,
K. Starosta,
R. Wadsworth,
A. N. Wilson,
J. N. Wilson
[show abstract]
[hide abstract]
ABSTRACT: Rotational bands have been studied to high spins in the neutron-deficient 124,125Ce nuclei. The nuclei were populated using the 64Zn(64Zn,2p2n)124Ce and 64Zn(64Zn,2pn)125Ce reactions, with a beam energy of 260 MeV. High-fold γ-ray coincidence data were collected using the Gammasphere germanium-detector array. The Microball charged-particle detector array was used to provide channel selection. The previously established level structures of both 124,125Ce have been extended to high spins (∼30ℏ). In addition, several new bands have been identified. The alignments of pairs of h11∕2 neutrons and protons are observed in both nuclei. The alignments are compared to the predictions of Woods-Saxon cranked shell model calculations and to the systematics of h11∕2 quasiparticle alignments in neighboring nuclei. The apparent ability of the cranked shell model to explain the h11∕2 neutron alignments in 124,125Ce highlights the previously reported discrepancies between experiment and theory for the 128Ce isotope and, to a lesser extent, 126Ce.
Physical Review C 03/2004; 69(3). · 3.31 Impact Factor
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J. O'Brien,
C. J. Chiara,
M. Devlin, D. R. Lafosse,
F. Lerma,
M. Montero,
W. Reviol,
D. G. Sarantites,
C. Baktash,
H.-Q. Jin,
R. M. Clark,
I. Y. Lee,
A. O. Macchiavelli,
D. Soltysik,
S. L. Tabor
[show abstract]
[hide abstract]
ABSTRACT: The high-spin states of ^84Zr were populated via the reaction
^58Ni(^29Si, 2pn) at a beam energy of 130 MeV. Gamma-rays were detected
using the Gammasphere Ge-detector array, and the Microball array of CsI
detectors was used for charged particle selection. A gold-backed target
enabled the measurement of transistion quadrupole moments (lifetimes) of
the normal-deformed states via a Centroid-Shift Analysis. These data are
particularly relevant since ^84Zr is the only nucleus in the mass 80
region for which links have been established between the superdeformed
and the normal-deformed bands.
09/2003; -1.
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F. Lerma,
W. Reviol,
C. J. Chiara,
M. Devlin, D. R. LaFosse,
D. G. Sarantites,
C. Baktash,
H.-Q. Jin,
R. M. Clark,
I. Y. Lee,
A. O. Macchiavelli,
W. Satula,
D. Soltysik,
S. L. Tabor,
R. Wyss
Physical Review C 07/2003; 68(1). · 3.31 Impact Factor
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F. Lerma,
W. Reviol,
C. J. Chiara,
M. Devlin, D.R. LaFosse,
D. G. Sarantites,
Cyrus Baktash,
Haoqiang Jin,
R. M. Clark,
I. Y. Lee,
A. O. Macchiavelli,
W. Satula,
D. Soltysik,
Samuel L Tabor,
R. Wyss
Physical Review C. 03/2003; 67(4).
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J. Pavan,
S. L. Tabor,
A. V. Afanasjev,
C. Baktash,
F. Cristancho,
M. Devlin,
J. Döring,
C. J. Gross,
G. D. Johns,
R. A. Kaye, D. R. LaFosse,
I. Y. Lee,
F. Lerma,
A. O. Macchiavelli,
I. Ragnarsson,
D. G. Sarantites,
G. N. Solomon
[show abstract]
[hide abstract]
ABSTRACT: Two experiments have been performed using the 58Ni(32S,3p) reaction at 135 MeV with Gammasphere and the Microball to study the high-spin structure of the transitional nucleus 87Nb. The first experiment using a thin target provided a considerable extension and refinement of the level scheme, as well as firm spin assignments from directional correlation of oriented nuclei. Sub-picosecond lifetimes were measured in the second backed-target experiment using the Doppler-shift attenuation method. The lifetimes imply a rather modest average deformation of β2∼0.1, but with considerable variation from state to state. Strong alternations were observed in the B(M1) strengths of transitions between some pairs of bands. The experimental results were compared with calculations performed within the cranked Nilsson-Strutinsky approach. The calculations generally reproduce the irregularities in the structure of the yrast lines and plunging transition quadrupole moments Qt within the bands explaining them as reflections of configuration changes and an approach of band termination, respectively.
Physical Review C 03/2003; 67(3). · 3.31 Impact Factor
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W Reviol,
D G Sarantites,
F Lerma,
M Devlin, D R LaFosse,
C J Chiara,
R Wyss,
C Baktash,
H -Q Jin,
S L Tabor,
D Soltysik,
R M Clark,
I Y Lee,
A O Macchiavelli,
R W MacLeod
Proc.Frontiers of Nuclear Structure; 01/2003
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F Lerma,
W Reviol,
C J Chiara,
M Devlin, D R LaFosse,
D G Sarantites,
C Baktash,
H -Q Jin,
R M Clark,
I Y Lee,
A O Macchiavelli,
W Satula,
D Soltysik,
S L Tabor,
R Wyss
Physical Review C 01/2003; 67:044310. · 3.31 Impact Factor
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A N Wilson, D R LaFosse,
J F Smith,
C J Chiara,
A J Boston,
M P Carpenter,
H J Chantler,
R Charity,
P T W Choy,
M Devlin, [......],
R V F Janssens,
D G Jenkins,
N S Kelsall,
F G Kondev,
T Koike,
E S Paul,
D G Sarantites,
D Seweryniak,
K Starosta,
R Wadsworth
Physical Review C 08/2002; 66(2):021305. · 3.31 Impact Factor
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H. J. Chantler,
E. S. Paul,
A. J. Boston,
M. P. Carpenter,
R. Charity,
C. J. Chiara,
P. T. W. Choy,
C. N. Davids,
M. Devlin,
A. M. Fletcher, [......],
N. S. Kelsall,
T. Koike, D. R. LaFosse,
P. J. Nolan,
D. G. Sarantites,
D. Seweryniak,
J. F. Smith,
K. Starosta,
R. Wadsworth,
A. N. Wilson
[show abstract]
[hide abstract]
ABSTRACT: High-spin states have been studied in neutron-deficient 57124La67, populated through the 64Zn(64Zn,3pn) reaction at 260 MeV. The Gammasphere γ-ray spectrometer has been used in conjunction with the Microball charged-particle detector, the Neutron Shell, and the Argonne Fragment Mass Analyzer, in order to select evaporation residues of interest. The known band structures have been extended and new bands found. Most of the bands are linked together, allowing more consistent spin and parity assignments. Comparison of band properties to cranking calculations has allowed configuration assignments to be made and includes the first identification of the g9/2 proton-hole in an odd-odd lanthanum isotope. Two bands have been assigned a πh11/2⊗νh11/2 structure; the yrast one exhibits a signature inversion in its level energies below I=18.5ħ, while the excited one exhibits a signature inversion above I=18.5ħ.
Physical Review C 07/2002; 66(1). · 3.31 Impact Factor
