-
R. -D. Herzberg,
S. Moon, S. Eeckhaudt,
P. T. Greenlees,
P. A. Butler,
T. Page,
A. V. Afanasjev,
N. Amzal,
J. E. Bastin,
F. Becker, [......],
P. Reiter,
M. Sandzelius,
J. Saren,
Ch. Schlegel,
C. Scholey,
Ch. Theisen,
W. H. Trzaska,
J. Uusitalo,
A. Wiens,
H. J. Wollersheim
[show abstract]
[hide abstract]
ABSTRACT: In-beam gamma-ray and conversion electron spectroscopic studies have been performed on the 253
No nucleus. A strongly coupled rotational band has been identified and the improved statistics allows an assignment of the band
structure as built on the 9/2-[734]n\ensuremath 9/2^-[734]_{\nu} ground state. The results agree with previously known transition energies but disagree with the tentative structural assignments
made in earlier work.
European Physical Journal A 04/2012; 42(3):333-337. · 2.19 Impact Factor
-
F. Ghazi Moradi,
T. Bäck,
B. Cederwall,
M. Sandzelius,
A. Atac,
A. Johnson,
C. Qi,
R. Liotta,
B. Hadinia,
K. Andgren, [......],
J. Sorri,
J. Uusitalo,
E. Ganioğlu,
J. Thomson,
D. T. Joss,
R. D. Page,
S. Ertürk,
J. Simpson,
M. B. Gomez Hornillos,
L. Bianco
[show abstract]
[hide abstract]
ABSTRACT: Excited states in the odd-odd neutron deficient nucleus 162Ta (Z=73, N=89) have been studied for the first time. The gamma spectroscopy analysis using γ−γ−γ coincidences revealed a strongly coupled rotational structure that was established up to large angular momentum states. The rotational band was assigned to the configuration πh11/2[514]9/2⊗νi13/2[660]1/2 based on its rotational and electromagnetic properties. The data are interpreted within the framework of total Routhian surface calculations, which suggests an axially symmetric shape with a γ-soft minimum at β2≈0.16 and γ≈6∘. The crossing of the signature partners observed in heavier (N⩾91) odd-odd nuclides in this mass region is found to be absent at N=89. This might be correlated with a change in S-band structure above the paired band crossing at these neutron numbers.
Phys. Rev. C. 12/2011; 84(6).
-
D. M. Cullen,
P. J. R Mason,
C. Scholey, S. Eeckhaudt,
T. Grahn,
P. T. Greenlees,
U. Jakobsson,
P. M. Jones,
R. Julin,
S. Juutinen, [......],
J. Pakarinen,
P. Peura,
M. G. Procter,
P. Rahkila,
S. V. Rigby,
J. Sarén,
J. Sorri,
J. Uusitalo,
B. J. Varley,
M. Venhart
[show abstract]
[hide abstract]
ABSTRACT: Recoil-isomer tagging with the 54Fe+92Mo reaction was used to establish a 10(2)-μs isomeric state in 139Eu. Prompt versus delayed γ-ray coincidence data have revealed the presence of a prompt rotational band built upon the isomer. The alignment properties of the states in this band show that the isomer is based upon a proton g7/2 configuration. The decay of the isomer takes place through a single 26-keV E1 transition. The γ-ray transition strength for this decay is consistent with those established in the neighboring isomeric gamma-soft nuclei. In these nuclei, isomers are expected to form as a consequence of differences in nuclear shapes or configurations, and the natural hindrance associated with configuration-changing E1 transitions. The isomeric nature of the state in 139Eu is reasoned to be because of difference in shape of the proton g7/2 state and the proton h11/2 ground state to which it decays.
Phys. Rev. C. 01/2011; 83(1).
-
K. Lagergren,
D. T. Joss,
E. S. Paul,
B. Cederwall,
J. Simpson,
D. E. Appelbe,
C. J. Barton, S. Eeckhaudt,
T. Grahn,
P. T. Greenlees, [......],
P. Nieminen,
R. D. Page,
J. Pakarinen,
J. Perkowski,
P. Rahkila,
C. Scholey,
J. Uusitalo,
D. D. Warner,
D. R. Wiseman,
R. Wyss
[show abstract]
[hide abstract]
ABSTRACT: Excited states in the neutron-deficient odd-Z nuclide 161Ta were identified for the first time using the 106Cd(58Ni,3pγ) reaction at a beam energy of 270 MeV. The πh11/2 band, yrast at low spin, was observed up to (47/2-) and a further four strongly coupled bands have been established to high spin. Quasiparticle configuration assignments for the new band structures have been made on the basis of cranked shell model calculations. This work suggests that the negative-parity ν(f7/2,h9/2) orbitals are responsible for the first rotational alignment in the πh11/2 band.
Phys. Rev. C. 01/2011; 83(1).
-
K Lagergren,
D T Joss,
E S Paul,
B Cederwall,
J Simpson,
D E Appelbe,
C J Barton, S Eeckhaudt,
T Grahn,
P T Greenlees, [......],
P Nieminen,
R D Page,
J Pakarinen,
J Perkowski,
P Rahkila,
C Scholey,
J Uusitalo,
D D Warner,
D R Wiseman,
R Wyss
Phys.Rev. C. 01/2011; 83:014313.
-
Ghazi F Moradi,
T Back,
B Cederwall,
M Sandzelius,
A Atac,
A Johnson,
C Qi,
R Liotta,
B Hadinia,
K Andgren, [......],
J Sorri,
J Uusitalo,
E Ganioglu,
J Thomson,
D T Joss,
R D Page,
S Erturk,
J Simpson,
Gomez M B Hornillos,
L Bianco
Phys.Rev. C. 01/2011; 84:064312.
-
D M Cullen,
P J R Mason,
C Scholey, S Eeckhaudt,
T Grahn,
P T Greenlees,
U Jakobsson,
P M Jones,
R Julin,
S Juutinen, [......],
J Pakarinen,
P Peura,
M G Procter,
P Rahkila,
S V Rigby,
J Saren,
J Sorri,
J Uusitalo,
B J Varley,
M Venhart
Physical Review C. 01/2011; 83(1).
-
E. Ideguchi,
B. Cederwall,
E. Ganioğlu,
B. Hadinia,
K. Lagergren,
T. Bäck,
A. Johnson,
R. Wyss, S. Eeckhaudt,
T. Grahn, [......],
J. Pakarinen,
P. Rahkila,
C. Scholey,
J. Uusitalo,
D. T. Joss,
E. S. Paul,
D. R. Wiseman,
R. Wadsworth,
A. V. Afanasjev,
I. Ragnarsson
[show abstract]
[hide abstract]
ABSTRACT: High-spin states in the neutron-deficient nucleus 107In were studied via the 58Ni(52Cr,3p) reaction. In-beam γ rays were measured using the JUROGAM detector array. A rotational cascade consisting of ten γ-ray transitions, which decays to the 19/2+ level at 2.002 MeV, was observed. The band exhibits the features typical for smooth terminating bands that also appear in rotational bands of heavier nuclei in the A ~ 100 region. The results are compared with total Routhian surface and cranked Nilsson-Strutinsky calculations.
Phys. Rev. C. 03/2010; 81(3).
-
E. Ideguchi,
B. Cederwall,
E. Ganioğlu,
B Hadinia,
K. Lagergren,
T. Bäck,
A Johnson,
R. Wyss, S Eeckhaudt,
T Grahn, [......],
J Pakarinen,
P Rahkila,
C Scholey,
J Uusitalo,
D T Joss,
E. S. Paul,
D. R. Wiseman,
R Wadsworth,
A. V. Afanasjev,
I Ragnarsson
[show abstract]
[hide abstract]
ABSTRACT: High-spin states in the neutron deficient nucleus $^{107}$In were studied via the $^{58}$Ni($^{52}$Cr, 3p) reaction. In-beam $\gamma$ rays were measured using the JUROGAM detector array. A rotational cascade consisting of ten $\gamma$-ray transitions which decays to the 19/2$^{+}$ level at 2.002 MeV was observed. The band exhibits the features typical for smooth terminating bands which also appear in rotational bands of heavier nuclei in the A$\sim$100 region. The results are compared with Total Routhian Surface and Cranked Nilsson-Strutinsky calculations. Comment: 27 pages, 16 figures, accepted for publication in Physical Review C
02/2010;
-
J. Thomson,
D. T. Joss,
E. S. Paul,
C. Scholey,
J. Simpson,
S. Ertürk,
L. Bianco,
B. Cederwall,
I. G. Darby, S. Eeckhaudt, [......],
D. O’Donnell,
R. D. Page,
J. Pakarinen,
P. Rahkila,
N. Rowley,
M. Sandzelius,
P. J. Sapple,
J. Sarén,
J. Sorri,
J. Uusitalo
[show abstract]
[hide abstract]
ABSTRACT: Excited states in the neutron-deficient nuclide 163W were investigated using the 106Cd(60Ni,2pn)163W reaction at a beam energy of 270 MeV. The level scheme for 163W was extended significantly with the observation of five new band structures. The yrast band based on a 13/2+ isomeric state is extended up to (57/2+). Two band structures were established on the 7/2- ground state. Quasiparticle configuration assignments for the new band structures were made on the basis of cranked Woods-Saxon shell-model calculations. The results reported in this article suggest that the negative-parity ν(f7/2,h9/2) orbitals are responsible for the first rotational alignment in the yrast band.
Phys. Rev. C. 01/2010; 81(1).
-
C. Scholey,
K. Andgren,
L. Bianco,
B. Cederwall,
I. G. Darby, S. Eeckhaudt,
S. Ertürk,
M. B. Gomez Hornillos,
T. Grahn,
P. T. Greenlees, [......],
R. D. Page,
J. Pakarinen,
P. Rahkila,
J. Sarén,
M. Sandzelius,
J. Simpson,
J. Sorri,
J. Thomson,
J. Uusitalo,
M. Venhart
[show abstract]
[hide abstract]
ABSTRACT: Decay paths, half-lives, and excitation energies of the i13/2 bandheads of the neutron-deficient nuclei 171Pt, 167Os, and 163W have been established for the first time. Gamma-ray transitions, X-rays, and internal conversion electrons have been observed, allowing internal-conversion coefficients to be measured and B(M2) reduced transition probabilities to be extracted. These results elucidate the low-lying single-quasiparticle structures and give the energy level spacings between the νf7/2, νh9/2, and νi13/2 quasineutron states for all three nuclei. Moreover, ground-state spin assignments have been made for the first time, along with the measurement of the α-decay branching ratio for 171Pt. The decay paths of the i13/2 bandheads were followed by favored α decays, indicating that all three nuclei have the same Iπ=7/2- ground state.
Phys. Rev. C. 01/2010; 81(1).
-
D. M. Cullen,
P. J. R Mason,
S. V. Rigby,
C. Scholey, S. Eeckhaudt,
T. Grahn,
P. T. Greenlees,
U. Jakobsson,
P. M. Jones,
R. Julin, [......],
P. Nieminen,
M. Nyman,
J. Pakarinen,
P. Peura,
P. Rahkila,
J. Sarén,
J. Sorri,
J. Uusitalo,
B. J. Varley,
M. Venhart
[show abstract]
[hide abstract]
ABSTRACT: Recoil-isomer tagging at the Accelerator Laboratory of the University of Jyväskylä has been used to establish the isomeric nature of a known (7-) excited state in the doubly odd nucleus 134Pm. The isomeric state was determined to have a half-life of 20(1) μs and was populated from the decay of a πh11/2⊗νh11/2 band using the 92Mo(54Fe,2α3pn) reaction at 305 and 315 MeV. The isomer decays by a 71-keV transition that provides an intermediate step in linking the established 134Pm high-spin level scheme to the lower-spin states observed from the β decay of 134Sm. Electron-conversion analysis for the 71-keV γ-ray transition reveals that it is of E1 character and its small reduced-transition probability suggests that 134Pm may have a nuclear shape more rigid than that of the neighboring nuclei.
Phys. Rev. C. 08/2009; 80(2).
-
S Ketelhut,
P T Greenlees,
D Ackermann,
S Antalic,
E Clément,
I G Darby,
O Dorvaux,
A Drouart, S Eeckhaudt,
B J P Gall, [......],
C Scholey,
J Sorri,
A Steer,
B Sulignano,
Ch Theisen,
J Uusitalo,
M Venhart,
M Zielinska,
M Bender,
P-H Heenen
[show abstract]
[hide abstract]
ABSTRACT: The rotational band structure of 255Lr has been investigated using advanced in-beam gamma-ray spectroscopic techniques. To date, 255Lr is the heaviest nucleus to be studied in this manner. One rotational band has been unambiguously observed and strong evidence for a second rotational structure was found. The structures are tentatively assigned to be based on the 1/2-[521] and 7/2-[514] Nilsson states, consistent with assignments from recently obtained alpha decay data. The experimental rotational band dynamic moment of inertia is used to test self-consistent mean-field calculations using the Skyrme SLy4 interaction and a density-dependent pairing force.
Physical Review Letters 06/2009; 102(21):212501. · 7.37 Impact Factor
-
D M Cullen,
P J R Mason,
S V Rigby,
C Scholey, S Eeckhaudt,
T Grahn,
P T Greenlees,
U Jakobsson,
P M Jones,
R Julin, [......],
P Nieminen,
M Nyman,
J Pakarinen,
P Peura,
P Rahkila,
J Saren,
J Sorri,
J Uusitalo,
B J Varley,
M Venhart
[show abstract]
[hide abstract]
ABSTRACT: Recoil-isomer tagging at the Accelerator Laboratory of the University of Jyvaumlskylauml has been used to establish the isomeric nature of a known (7(-)) excited state in the doubly odd nucleus Pm-134. The isomeric state was determined to have a half-life of 20(1) mu s and was populated from the decay of a pi h(11/2)circle times nu h(11/2) band using the Mo-92(Fe-54,2 alpha 3pn) reaction at 305 and 315 MeV. The isomer decays by a 71-keV transition that provides an intermediate step in linking the established Pm-134 high-spin level scheme to the lower-spin states observed from the beta decay of Sm-134. Electron-conversion analysis for the 71-keV gamma-ray transition reveals that it is of E1 character and its small reduced-transition probability suggests that Pm-134 may have a nuclear shape more rigid than that of the neighboring nuclei.
Physical Review C. 01/2009; 80(2).
-
P J R Mason,
D M Cullen,
C Scholey, S Eeckhaudt,
T Grahn,
P T Greenlees,
U Jakobsson,
P M Jones,
R Julin,
S Juutinen, [......],
M Nyman,
J Pakarinen,
P Peura,
P Rahkila,
S V Rigby,
J Saren,
J Sorri,
J Uusitalo,
B J Varley,
M Venhart
[show abstract]
[hide abstract]
ABSTRACT: Recoil-isomer tagging has been used to characterize the states built upon an I-pi=8(+) isomer in Tb-142. High-spin states of the neutron-deficient nucleus Tb-142 were populated using an Fe-54 beam, accelerated onto a Mo-92 target of thickness similar to 500 mu g/cm(2) at energies of 245, 252, and 265 MeV using the K130 cyclotron at the University of Jyvaskyla, Finland. Use of the JUROGAM target-position Ge-detector array coupled with the GREAT focal-plane spectrometer at the RITU gas-filled recoil separator has significantly increased the efficiency of the isomer-tagging technique. The rotational band built upon the I-pi=8(+) isomeric state was established with isomer-tagged gamma-gamma coincidence data and angular distributions were measured for some of the more intensely populated states. Two previously unobserved bands that bypass the isomer were also established. The new data have been interpreted within the framework of the cranked-shell model. The data show good agreement with the calculated triaxial nuclear shape with gamma=-30(degrees) for the Tb-142m2 isomeric state. The B(M1)/B(E2) branching ratios, nuclear alignment, signature splitting, and reduced transition probability, B(E1), of the isomeric state have been systematically compared with those of the neighboring nuclei. These comparisons give further evidence for the pi h(11/2)circle times nu h(11/2) configuration of the isomer.
Physical Review C. 01/2009; 79(2):10.
-
M Sandzelius,
B Cederwall,
E Ganioglu,
J Thomson,
K Andgren,
L Bianco,
T Back, S Eeckhaudt,
S Erturk,
Gomez M B Hornillos, [......],
M Leino,
M Nyman,
R D Page,
P Rahkila,
J Saren,
C Scholey,
J Simpson,
J Sorri,
J Uusitalo,
R Wyss
Phys.Rev. C. 01/2009; 80:054316.
-
R. D. Page,
L. Bianco,
I. G. Darby,
D. T. Joss,
R. J. Cooper,
T. Grahn,
D. S. Judson,
P. J. Sapple,
J. Thomson,
J. Simpson,
M. Labiche,
D. O'Donnell,
J. S. Al-Khalili,
A. J. Cannon,
P. D. Stevenson,
E. B. Suckling, S. Eeckhaudt,
P. T. Greenlees,
P. M. Jones,
R. Julin
[show abstract]
[hide abstract]
ABSTRACT: The energy of the vh{sub 9/2} orbital in nuclei above N = 82 drops rapidly in energy relative to the vf{sub 7/2} orbital as the occupancy of the {pi}h{sub 11/2} orbital increases. These two neutron orbitals become nearly degenerate as the proton drip line is approached. In this work, we have discovered the new nuclides {sup 161}Os and {sup 157}W, and studied the decays of the proton emitter {sup 160}Re in detail. The {sup 161}Os and {sup 160}Re nuclei were produced in reactions of 290, 300 and 310 MeV {sup 58}Ni ions with an isotopically enriched {sup 106}Cd target, separated in-flight using the RITU separator and implanted into the GREAT spectrometer. The {sup 161}Os{alpha} a decays populated the new nuclide {sup 157}W, which decayed by {beta}-particle emission. The {beta} decay fed the known {alpha}-decaying 1/2{sup +} and 11/2{sup -} states in {sup 157}Ta, which is consistent with a vf{sub 7/2} ground state in {sup 157}W. The measured {alpha}-decay energy and half-life for {sup 161}Os correspond to a reduced {alpha}-decay width that is compatible with s-wave {alpha}-particle emission, implying that its ground state is also a vf{sub 7/2} state. Over 7000 {sup 160}Re nuclei were produced and the {gamma} decays of a new isomeric state feeding the {pi}d{sub 3/2} level in {sup 160}Re were discovered, but no evidence for the proton or a decay of the expected {pi}h{sub 11/2} state could be found. The isomer decays offer a natural explanation for this non-observation and provides a striking example of the influence of the near degeneracy of the vh{sub 9/2} and vf{sub 7/2} orbitals on the properties of nuclei in this region.
AIP Conference Proceedings 11/2008; 1072(1).
-
S. Ketelhut,
P. T. Greenlees,
A. Chatillon,
E. Bouchez,
P. A. Butler,
E. Clément,
O. Dorvaux, S. Eeckhaudt,
B. J. P. Gall,
A. Görgen, [......],
J. Perkowski,
P. Rahkila,
M. Rousseau,
J. Sarén,
C. Scholey,
Ch. Theisen,
J. Uusitalo,
J. N. Wilson,
P. Bonche,
P.-H. Heenen
[show abstract]
[hide abstract]
ABSTRACT: Two rotational bands have been found in the transfermium nuclei
251Md and 255Lr, the latter being the heaviest
nucleus so far studied in-beam. Both are assigned to a
[521]1/2- Nilsson state by comparison to theory. The
experiments have been carried out in the Accelerator Laboratory of the
University of Jyväskylä (JYFL), where the array of germanium
detectors JUROGAM was used in conjunction with the recoil-seperator RITU
and the focal-plane setup GREAT for gamma-spectroscopic studies.
04/2008; 1012:368-370.
-
P. T. Greenlees,
R.-D. Herzberg,
S. Ketelhut,
D. Ackermann,
P. A. Butler,
A. Chatillon, S. Eeckhaudt,
B. J. P. Gall,
T. Grahn,
C. Gray-Jones, [......],
M. Richer,
D. Rostron,
C. Santos,
J. Sarén,
C. Scholey,
J. Sorri,
S. K. Tandel,
Ch. Theisen,
J. Uusitalo,
M. Venhart
[show abstract]
[hide abstract]
ABSTRACT: Advances in spectroscopic techniques have meant that heavy nuclei in the
upper right-hand corner of the nuclear chart have become amenable to
detailed study. This detailed spectroscopic data can provide a stringent
test for current nuclear structure theories. Experiments to investigate
the structure of nuclei in the region of 254No can yield
information concerning moments of inertia, stability against fission
with rotation, single-particle properties, excitation energies of two
quasi-particle states, and so on. A brief overview of the techniques
used and recent results from studies in the region of 254No
are presented, along with a summary of future developments which will
allow further advances to be made.
04/2008; 1012:56-63.
-
S V Rigby,
D M Cullen,
P J R Mason,
D T Scholes,
C Scholey,
P Rahkila, S Eeckhaudt,
T Grahn,
P Greenlees,
P M Jones,
R Julin,
S Juutinen,
H Kettunen,
M Leino,
A P Leppanen,
P Nieminen,
M Nyman,
J Pakarinen,
J Uusitalo
[show abstract]
[hide abstract]
ABSTRACT: An experiment has been performed to populate several extremely neutron-deficient nuclei around the mass-140 region of the nuclear chart, using a beam of Fe-54 on a Mo-92 target at an energy of 315 MeV. Analysis of these data using recoil-isomer tagging has established that the yrast pi h(11/ 2) circle times nu h(11/ 2), J(pi) = (8(+)), bandhead state in Pm-136 is isomeric with a half-life of 1.5(1) mu s. This isomeric state decays via a 43-keV, probable-E1 transition to a J(pi) = (7(-)) state. Consideration of the theoretical Nilsson orbitals near the Fermi surface suggests that the J(pi) = (8(+)) state has a nu h(11/ 2)[505]11(-)/2 circle times pi h(11/2)[532]5(-)/2 configuration, which decays to the J(pi) = (7(-)) state with a nu h(11/2)[505]11(-)/2 circle times pi d(5/2)[411]3(+)/2 configuration. Differences in the shape-driving effects for these two configurations is reasoned to be responsible for the long half-life of the J(pi) = (8(+)) isomeric state. The non-observation of other gamma rays in prompt or delayed coincidence with the 43-keV transition suggests that this transition may feed another, longer lived isomeric state with a half-life of the order of milliseconds or greater. However, the present experiment was not sensitive to the decay of this new J(pi) = (7(-)) state by internal conversion or even beta decay.
Physical Review C. 01/2008; 78(3):7.
