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Sökning: WFRF:(Pakarinen P)

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1.
  • Wadsworth, R., et al. (författare)
  • THE NORTHWEST FRONTIER : SPECTROSCOPY OF N similar to Z NUCLEI BELOW MASS 100
  • 2009
  • Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 40:3, s. 611-620
  • Tidskriftsartikel (refereegranskat)abstract
    • The spectroscopy and structure of excited states of N similar to Z nuclei in the mass 70-100 region has been investigated using two techniques. In the A similar to 70-80 region fusion evaporation reactions coupled with the recoil-beta-tagging method have been employed at Jyvaskyla to study low-lying states in odd-odd N = Z nuclei. Results from these and other data for known odd-odd nuclei above mass 60 will be discussed. In the heavier mass 90 region a fragmentation experiment has been performed using the RIS-ING/FRS setup at GSI. This experiment was primarily aimed at searching for spin gap isomers in nuclei around A similar to 96. The objectives of the latter experiment will be discussed.
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2.
  • Bree, N, et al. (författare)
  • Shape Coexistence in the Neutron-Deficient Even-Even Hg182-188 Isotopes Studied via Coulomb Excitation.
  • 2014
  • Ingår i: Physical Review Letters. - 1079-7114. ; 112:16
  • Tidskriftsartikel (refereegranskat)abstract
    • Coulomb-excitation experiments to study electromagnetic properties of radioactive even-even Hg isotopes were performed with 2.85 MeV/nucleon mercury beams from REX-ISOLDE. Magnitudes and relative signs of the reduced E2 matrix elements that couple the ground state and low-lying excited states in Hg182-188 were extracted. Information on the deformation of the ground and the first excited 0+ states was deduced using the quadrupole sum rules approach. Results show that the ground state is slightly deformed and of oblate nature, while a larger deformation for the excited 0+ state was noted in Hg182,184. The results are compared to beyond mean field and interacting-boson based models and interpreted within a two-state mixing model. Partial agreement with the model calculations was obtained. The presence of two different structures in the light even-mass mercury isotopes that coexist at low excitation energy is firmly established.
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3.
  • Wrzosek-Lipska, K., et al. (författare)
  • Electromagnetic properties of low-lying states in neutron-deficient Hg isotopes : Coulomb excitation of 182Hg, 184Hg, 186Hg and 188Hg
  • 2019
  • Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 55:8
  • Tidskriftsartikel (refereegranskat)abstract
    • The neutron-deficient mercury isotopes serve as a classical example of shape coexistence, whereby at low energy near-degenerate nuclear states characterized by different shapes appear. The electromagnetic structure of even-mass 182-188 Hg isotopes was studied using safe-energy Coulomb excitation of neutron-deficient mercury beams delivered by the REX-ISOLDE facility at CERN. The population of 01,2+, 21,2+ and 41+ states was observed in all nuclei under study. Reduced E2 matrix elements coupling populated yrast and non-yrast states were extracted, including their relative signs. These are a sensitive probe of shape coexistence and may be used to validate nuclear models. The experimental results are discussed in terms of mixing of two different configurations and are compared with three different model calculations: the Beyond Mean Field model, the Interacting Boson Model with configuration mixing and the General Bohr Hamiltonian. Partial agreement with experiment was observed, hinting to missing ingredients in the theoretical descriptions.
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4.
  • Ketelhut, S., et al. (författare)
  • gamma-Ray Spectroscopy at the Limits : First Observation of Rotational Bands in Lr-255
  • 2009
  • Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:21, s. 212501-
  • Tidskriftsartikel (refereegranskat)abstract
    • The rotational band structure of Lr-255 has been investigated using advanced in-beam gamma-ray spectroscopic techniques. To date, Lr-255 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.
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5.
  • Parr, E., et al. (författare)
  • Single-particle states and parity doublets in odd- Z Ac 221 and Pa 225 from α -decay spectroscopy
  • 2022
  • Ingår i: Physical Review C. - 2469-9985. ; 105:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Low-lying states in the odd-Z isotopes Ac13289221 and Pa13491225 have been studied using α-particle and αγ-coincidence spectroscopy in the Pa225→Ac221→Fr217 decay chain. Ground-state spin and parity assignments of Iπ = 5/2- are proposed for both Ac221 and Pa225, with the odd proton occupying the ω = 5/2 orbital of the quadrupole-octupole deformed shell model in both nuclei. In Ac221, excited states in the bands based on the ω = 5/2 and ω = 3/2 orbitals have been identified, including proposed parity-doublet states. The results suggest that reflection-asymmetric deformation of the ground state persists in the odd-A members of the isotope chains down to N = 132 for Ac and N = 134 for Pa, before reaching the transitional region at N = 130.
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6.
  • Petts, A., et al. (författare)
  • Lifetime measurements and coulomb excitation of light Hg nuclei
  • 2009
  • Ingår i: Capture Gamma-Ray Spectroscopy and Related Topics. - : American Institute of Physics (AIP). - 9780735406230 ; , s. 414-418
  • Konferensbidrag (refereegranskat)abstract
    • Two complementary experimental programs have taken place to investigate the origin and evolution of shape coexistence in the light mercury region. Recoil Distance Doppler-shift measurements were performed at the University of Jyväskylä utilizing the Köln plunger device in conjunction with the JUROGAM + RITU + GREAT setup. In addition, Coulomb excitation measurements of 184,186,188Hg were performed at REX-ISOLDE using the MINIBALL Ge-detector array. The results of the lifetime measurements of the yrast states up to Iπ = 10+ in 182Hg are reported. Preliminary analysis of the Coulomb excitation data is also discussed.
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7.
  • Davis-Merry, T. R., et al. (författare)
  • Collective excitations in the transitional nuclei Re-163 and Re-165
  • 2015
  • Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 91:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Excited states in the neutron-deficient nuclei (163)(75) Re-88 and (165)(75) Re-90 were populated in the Cd-106(Ni-60, p2n gamma) and Mo-92(Kr-78, 3p2n gamma) fusion-evaporation reactions at bombarding energies of 270 and 380 MeV, respectively.. rays were detected at the target position using the JUROGAM spectrometer while recoiling ions were separated in-flight by the RITU gas-filled recoil separator and implanted in the GREAT spectrometer. The energy level schemes for Re-163 and Re-165 were identified using recoil-decay correlation techniques. At low spin, the yrast bands of these isotopes consist of signature partner bands based on a single pi h(11/2) quasiproton configuration. The bands display large energy splitting consistent with the soft triaxial shape typical of transitional nuclei above N = 82. The configurations of the excited states are proposed within the framework of the cranked shell model.
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8.
  • Gaffney, L. P., et al. (författare)
  • Collectivity in the light radon nuclei measured directly via Coulomb excitation
  • 2015
  • Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 91:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Shape coexistence in heavy nuclei poses a strong challenge to state-of-the-art nuclear models, where several competing shape minima are found close to the ground state. A classic region for investigating this phenomenon is in the region around Z = 82 and the neutron midshell at N = 104. Purpose: Evidence for shape coexistence has been inferred from a-decay measurements, laser spectroscopy, and in-beam measurements. While the latter allow the pattern of excited states and rotational band structures to be mapped out, a detailed understanding of shape coexistence can only come from measurements of electromagnetic matrix elements. Method: Secondary, radioactive ion beams of Rn-202 and Rn-204 were studied by means of low-energy Coulomb excitation at the REX-ISOLDE in CERN. Results: The electric-quadrupole (E2) matrix element connecting the ground state and first excited 2(1)(+) state was extracted for both Rn-202 and Rn-204, corresponding to B(E2; 2(1)(+) -> 0(1)(+)) = 29(-8)(+8) and 43(-12)(+17) W.u., respectively. Additionally, E2 matrix elements connecting the 2(1)(+) state with the 4(1)(+) and 2(2)(+) states were determined in Rn-202. No excited 0(+) states were observed in the current data set, possibly owing to a limited population of second-order processes at the currently available beam energies. Conclusions: The results are discussed in terms of collectivity and the deformation of both nuclei studied is deduced to be weak, as expected from the low-lying level-energy schemes. Comparisons are also made to state-of-the-art beyond-mean-field model calculations and the magnitude of the transitional quadrupole moments are well reproduced.
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9.
  • Joss, D. T., et al. (författare)
  • Evolving collective structures in the transitional nuclei W-162 and W-164
  • 2016
  • Ingår i: PHYSICAL REVIEW C. - : American Physical Society. - 2469-9985. ; 93:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Excited states in the neutron-deficient nuclides(74)(162)W(88) and W-164(74)90 were investigated by using the gamma-ray spectrometer Jurogam. A change in structure is apparent from the first rotational alignments in W-162 and W-164, whose rotationally aligned bands are interpreted as nu(h(9/2))(2) and nu(i(13/2))(2) configurations, respectively. The level schemes have been extended using recoil (-decay) correlations with the observation of excited collective structures. Configuration assignments have been made on the basis of comparisons of the deduced aligned angular momentum, as a function of rotational frequency, with the predictions of the cranked shell model.
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10.
  • Procter, M. G., et al. (författare)
  • Anomalous transition strength in the proton-unbound nucleus (109)(53)I56
  • 2011
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 704:3, s. 118-122
  • Tidskriftsartikel (refereegranskat)abstract
    • A lifetime measurement has been made for the first excited 11/2(+) state in the proton-unbound nucleus (109)(53)I56 using the recoil-distance Doppler-shift method in conjunction with recoil-proton tagging. The experimental reduced transition probability is considerably smaller than the prediction of theoretical shell-model calculations using the CD-Bonn nucleon-nucleon potential. The discrepancy between the theoretical and experimental reduced transition strengths in this work most likely arises from the inability of the current shell-model calculations to accurately account for the behavior of the unbound nuclear states.
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11.
  • Procter, M. G., et al. (författare)
  • Lifetime measurement in the proton-unbound nucleus 109I
  • 2011
  • Ingår i: AIP Conf. Proc.. - : AIP. - 9780735409835 ; , s. 105-110
  • Konferensbidrag (refereegranskat)abstract
    • The Recoil-Distance Doppler-shift method has been combined with Recoil-Decay Tagging for the first time to measure a lifetime in the proton-unbound nucleus 109I. The lifetime value was determined using the Differential Decay-Curve method in singles mode. The result has been compared to theoretical shell-model calculations in order to better understand the nature of unbound valence nucleons at the proton drip line.
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12.
  • Warr, N., et al. (författare)
  • The Miniball spectrometer
  • 2013
  • Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 49:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The Miniball germanium detector array has been operational at the REX (Radioactive ion beam EXperiment) post accelerator at the Isotope Separator On-Line facility ISOLDE at CERN since 2001. During the last decade, a series of successful Coulomb excitation and transfer reaction studies have been performed with this array, utilizing the unique and high-quality radioactive ion beams which are available at ISOLDE. In this article, an overview is given of the technical details of the full Miniball setup, including a description of the.-ray and particle detectors, beam monitoring devices and methods to deal with beam contamination. The specific timing properties of the REX-ISOLDE facility are highlighted to indicate the sensitivity that can be achieved with the full Miniball setup. The article is finalized with a summary of some physics highlights at REX-ISOLDE and the utilization of the Miniball germanium detectors at other facilities.
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13.
  • Grahn, T., et al. (författare)
  • Collectivity and configuration mixing in Pb186,188 and Po194
  • 2006
  • Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 97:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Lifetimes of prolate intruder states in Pb186 and oblate intruder states in Po194 have been determined by employing, for the first time, the recoil-decay tagging technique in recoil distance Doppler-shift lifetime measurements. In addition, lifetime measurements of prolate states in Pb188 up to the 8+ state were carried out using the recoil-gating method. The B(E2) values have been deduced from which deformation parameters |β2|=0.29(5) and |β2|=0.17(3) for the prolate and the oblate bands, respectively, have been extracted. The results also shed new light on the mixing between different shapes.
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14.
  • Lewis, M. C., et al. (författare)
  • Decay of a 19(-) isomeric state in Lu-156
  • 2018
  • Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 98:2
  • Tidskriftsartikel (refereegranskat)abstract
    • A multiparticle spin-trap isomeric state having a half-life of 179(4) ns and lying 2601 keV above the yrast 10(+) state in Lu-156 has been discovered. The Lu-156 nuclei were produced by bombarding isotopically enriched Cd-106 targets with beams of Ni-58 ions, separated in flight using the gas-filled separator RITU and their decays were measured using the GREAT spectrometer. Analysis of the main decay path that populates yrast states observed previously suggests a spin-parity assignment of 19(-) for the isomeric state, which is consistent with isomeric states identified in the N = 85 isotones. Comparison with other decay paths in Lu-156 indicates that the [pi h(11/)(2)(-1) circle times nu h(9/2)]10(+) state at the bottom of the yrast sequence is likely to be the a-decaying isomeric state, with the [pi h(11/)(2)(-1) circle times nu f(7/2)]9(+) state lying 62 keV above it. The relative ordering of the lowest-lying 9(+) and 10(+) states is inverted in Lu-156 compared with its odd-odd isotones.
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15.
  • Parr, E., et al. (författare)
  • Fine structure in the alpha decay of high-spin isomers in Lu-155 and Hf-156
  • 2018
  • Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 98:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Fine structure in the a decay of high-spin isomers in Lu-155( 25/2(-)) and Hf-156(8(+))has been studied for the first time using alpha gamma- coincidence analysis. Three new a decays from Lu-155(25/2(-)) and two from Hf-156(8(+)) have been identified, populating seniority s > 1 states in the N = 82 nuclei Tm-151 and Yb-152, respectively. The reduced hindrance factors of the a decays support the previous configuration assignments of the populated states. This is the first observation of states with excitation energy greater than 1.5 MeV being populated following a decay in nuclei outside of the Pb-208 region.
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16.
  • Briselet, R., et al. (författare)
  • Production cross section and decay study of Es 243 and Md 249
  • 2019
  • Ingår i: Physical Review C. - 2469-9985. ; 99:2
  • Tidskriftsartikel (refereegranskat)abstract
    • In the study of the odd-Z, even-N nuclei Es243 and Md249, performed at the University of Jyväskylä, the fusion-evaporation reactions Au197(Ca48,2n)Es243 and Tl203(Ca48,2n)Md249 have been used for the first time. Fusion-evaporation residues were selected and detected using a gas-filled separator coupled with its focal-plane spectrometer. For Es243, the recoil decay correlation analysis yielded a half-life of 24±3s and a maximum production cross section of 37±10nb. In the same way, a half-life of 26±1s, an α-branching ratio of 75±5%, and a maximum production cross section of 300±80nb were determined for Md249. The decay properties of Es245, the daughter of Md249, were also measured: an α-branching ratio of 54±7% and a half-life of 65±6s. Experimental cross sections were compared to the results of calculations performed using the kewpie2 statistical fusion-evaporation code.
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17.
  • Bäck, Torbjörn, et al. (författare)
  • First observation of gamma-rays from the proton emitter Au-171
  • 2003
  • Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 16:4, s. 489-494
  • Tidskriftsartikel (refereegranskat)abstract
    • Gamma-rays from the alpha- and proton-unstable nuclide Au-171 have been observed for the first time. The gamma-rays were correlated with both a proton- and an alpha-particle decay branch, confirming that the nucleus decays by alpha and proton emission from a single (11/2(-)) state. The measurement confirms the previously determined half-lives for these particle decays but the present values are of higher precision. In addition, a longer half-life than determined in previous work was measured for the proton-unstable tentative ground state. The results are discussed in relation to structures in neighbouring nuclei and compared with a Strutinsky-type TRS calculation.
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18.
  • Bäck, Torbjörn, et al. (författare)
  • Spectroscopy of the neutron-deficient nuclide Pt-171
  • 2003
  • Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 17:1, s. 1-5
  • Tidskriftsartikel (refereegranskat)abstract
    • A number of previously unobserved gamma-rays emitted from the neutron-deficient nuclide Pt-171 have been identified using the recoil decay tagging technique. The level scheme has been updated using information from gamma-gamma coincidences and angular distribution measurements. To further confirm the assignments of the gamma-rays to Pt-171, the events were correlated with the alpha-decay of the daughter nucleus Os-167.
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19.
  • Ertoprak, Aysegul, et al. (författare)
  • Evidence for octupole collectivity in 172Pt
  • 2020
  • Ingår i: European Physical Journal A. - : Springer. - 1434-6001 .- 1434-601X. ; 56:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Excited states in the extremely neutron-deficient nucleus 172Pt were populated via 96Ru(78Kr,2p) and 92Mo(83Kr,3n) reactions. The level scheme has been extended up to an excitation energy of  ~ 5 MeV and tentative spin-parity assignments up to Iπ = 18+. Linear polarization and angular distribution measurements were used to determine the electromagnetic E1 character of the dipole transitions connecting the positive-parity ground-state band with an excited side-band, firmly establishing it as a negative-parity band. The lowest member of this negative-parity structure was firmly assigned spin-parity 3-. In addition, we observed an E3 transition from this 3- state to the ground state, providing direct evidence for octupole collectivity in 172Pt. Large-scale shell model (LSSM) and total Routhian surface (TRS) calculations have been performed, supporting the interpretation of the 3- state as a collective octupole-vibrational state.
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20.
  • Gaffney, L. P., et al. (författare)
  • Studies of pear-shaped nuclei using accelerated radioactive beams
  • 2013
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 497:7448, s. 199-204
  • Tidskriftsartikel (refereegranskat)abstract
    • There is strong circumstantial evidence that certain heavy, unstable atomic nuclei are 'octupole deformed', that is, distorted into a pear shape. This contrasts with the more prevalent rugby-ball shape of nuclei with reflection-symmetric, quadrupole deformations. The elusive octupole deformed nuclei are of importance for nuclear structure theory, and also in searches for physics beyond the standard model; any measurable electric-dipole moment (a signature of the latter) is expected to be amplified in such nuclei. Here we determine electric octupole transition strengths (a direct measure of octupole correlations) for short-lived isotopes of radon and radium. Coulomb excitation experiments were performed using accelerated beams of heavy, radioactive ions. Our data on Rn-220 and Ra-224 show clear evidence for stronger octupole deformation in the latter. The results enable discrimination between differing theoretical approaches to octupole correlations, and help to constrain suitable candidates for experimental studies of atomic electric-dipole moments that might reveal extensions to the standard model.
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21.
  • Herzberg, R-D, et al. (författare)
  • Isomer spectroscopy in No-254
  • 2006
  • Ingår i: Physica Scripta. - 0031-8949 .- 1402-4896. ; T125, s. 73-77
  • Tidskriftsartikel (refereegranskat)abstract
    • Isomeric states in No-254 were investigated using a calorimetric method. Two different isomers were found with half-lives of T-1/2 = 266 +/- 2 ms and T-1/2 = 184 +/- 3 mu s, respectively. The dominant decay path of the 184 mu s isomer proceeds via states feeding the longer-lived 266 ms isomer. The 266 ms isomer in turn decays via a two-quasi-particle K = 3 band to the ground-state band. The full decay path was observed with the GREAT spectrometer located at the focal plane of the gas-filled separator RITU at the Accelerator Laboratory in Jyvskyl. This work sheds light on the two-quasi-particle structure in this transfermium nucleus.
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22.
  • Illana, A., et al. (författare)
  • Coulomb excitation of 74,76Zn
  • 2023
  • Ingår i: Physical Review C. - 2469-9985. ; 108:4
  • Tidskriftsartikel (refereegranskat)abstract
    • The first experiment using radioactive beams post-accelerated by the HIE-ISOLDE facility has enabled to obtain a precise set of B(E2) transition probabilities in neutron-rich 74,76Zn isotopes. The resulting B(E2; 2+1→0+1) values are consistent with those determined in earlier REX-ISOLDE measurements. While the B(E2; 4+1→2+1) transition probability in 76Zn is also in agreement with earlier Coulomb-excitation results, the value obtained for 74Zn is considerably lower. For the first time, a spectroscopic quadrupole moment of the 2+1 state was measured for an exotic nucleus in this mass region. A detailed comparison is presented with large-scale shell-model and Monte Carlo shell-model calculations.
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23.
  • Joss, D. T., et al. (författare)
  • The influence of quasineutron configurations on 161Ta and nearby odd-A nuclei
  • 2011
  • Ingår i: AIP Conf. Proc.. - : AIP. - 9780735409835 ; , s. 43-48
  • Konferensbidrag (refereegranskat)abstract
    • Several strongly coupled bands in the neutron-deficient nucleus 161Ta have been identified and quasiparticle configuration assignments have been made on the basis of rotational alignments and cranked shell model calculations. The level scheme elucidated for 161Ta highlights the competition between the ν(h 9/2) and ν(i 13/2) orbitals to form the yrast spectrum. The band structures in 161Ta also provide new insights into the structural features of other heavy odd-A nuclei populated with much lower reaction cross sections in this region at the proton drip line.
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24.
  • Kesteloot, N., et al. (författare)
  • Deformation and mixing of coexisting shapes in neutron-deficient polonium isotopes
  • 2015
  • Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 92:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Coulomb-excitation experiments are performed with postaccelerated beams of neutron-deficient Po-196,Po-198,Po-200,Po-202 isotopes at the REX-ISOLDE facility. A set of matrix elements, coupling the low-lying states in these isotopes, is extracted. In the two heaviest isotopes, Po-196,Po-198, the transitional and diagonal matrix elements of the 2(1)(+) state are determined. In Po-196,Po-198 multistep Coulomb excitation is observed, populating the 4(1)(+), 0(2)(+), and 2(2)(+) states. The experimental results are compared to the results from the measurement of mean-square charge radii in polonium isotopes, confirming the onset of deformation from Po-196 onwards. Three model descriptions are used to compare to the data. Calculations with the beyond-mean-field model, the interacting boson model, and the general Bohr Hamiltonian model show partial agreement with the experimental data. Finally, calculations with a phenomenological two-level mixing model hint at the mixing of a spherical structure with a weakly deformed rotational structure.
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25.
  • Korten, W., et al. (författare)
  • Physics opportunities with the Advanced Gamma Tracking Array : AGATA
  • 2020
  • Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 56:5
  • Forskningsöversikt (refereegranskat)abstract
    • New physics opportunities are opening up by the Advanced Gamma Tracking Array, AGATA, as it evolves to the full 4 pi instrument. AGATA is a high-resolution gamma -ray spectrometer, solely built from highly segmented high-purity Ge detectors, capable of measuring gamma rays from a few tens of keV to beyond 10 MeV, with unprecedented efficiency, excellent position resolution for individual gamma -ray interactions, and very high count-rate capability. As a travelling detector AGATA will be employed at all major current and near-future European research facilities delivering stable and radioactive ion beams.
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26.
  • Mach, H., et al. (författare)
  • Application of ultra-fast timing techniques to the study of exotic and weakly produced nuclei
  • 2005
  • Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 31:10, s. S1421-S1426
  • Tidskriftsartikel (refereegranskat)abstract
    • Ultra-fast time-delayed techniques have been recently applied in a number of studies where exotic nuclei were identified using advanced selection techniques. These include large Compton-suppressed Ge arrays, in-flight separators or recoil separators. Some of the new results are discussed in this presentation. Besides the results for Mg-32 and Pd-96, they include the first determination of the half-life of the 8(+) state in Ge-80, T-1/2 = 2.95(6) ns, and significantly more precise results for Mn-51 (3680 keV level) and V-48 (421 keV level), T-1/2 = 1760(40) ps and T-1/2.
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27.
  • Saygi, B., et al. (författare)
  • Reduced transition probabilities along the yrast line in W-166
  • 2017
  • Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 96:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Lifetimes of excited states in the yrast band of the neutron-deficient nuclide W-166 have been measured utilizing the DPUNS plunger device at the target position of the JUROGAM II gamma-ray spectrometer in conjunction with the RITU gas-filled separator and the GREAT focal-plane spectrometer. Excited states in W-166 were populated in the Mo-92(Kr-78, 4p) reaction at a bombarding energy of 380 MeV. The measurements reveal a low value for the ratio of reduced transitions probabilities for the lowest-lying transitions B(E2; 4(+)-> 2(+)) / B(E2; 2(+)-> 0(+)) = 0.33(5), compared with the expected ratio for an axially deformed rotor (B-4/2 = 1.43).
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28.
  • Scheck, M., et al. (författare)
  • Do nuclei go pear-shaped? Coulomb excitation of Rn-220 and Ra-224 at REX-ISOLDE (CERN)
  • 2015
  • Ingår i: Cgs15 - Capture Gamma-ray Spectroscopy and Related Topics. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 93, s. 01038-01038
  • Konferensbidrag (refereegranskat)abstract
    • The IS475 collaboration conducted Coulomb-excitation experiments with post-accelerated radioactive Rn-220 and Ra-224 beams at the REX-ISOLDE facility. The beam particles (E-beam: 2.83 MeV/u) were Coulomb excited using Ni-60, Cd-14, and Sn-120 scattering targets. De-excitation gamma-rays were detected employing the Miniball array and scattered particles were detected in a silicon detector. Exploiting the Coulomb-excitation code GOSIA for each nucleus several matrix elements could be obtained from the measured gamma-ray yields. The extracted < 3 parallel to E3 parallel to 0(+)> matrix element allows for the conclusion that, while Rn-220 represents an octupole vibrational system, Ra-224 has already substantial octupole correlations in its ground state. This finding has i(m)plications for the search of CP-violating Schiff moments in the atomic systems of the adjacent odd-mass nuclei.
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29.
  • Scholey, C., et al. (författare)
  • In-beam and decay spectroscopy of very neutron deficient iridium nuclei
  • 2005
  • Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 31:10, s. S1719-S1722
  • Tidskriftsartikel (refereegranskat)abstract
    • Iridium nuclei at and beyond the proton drip line have been studied via fusion evaporation reactions. A reaction of Mo-92(Kr-78, p2n) at a beam energy of 360 MeV and target thickness 500 mu g cm(-2) was employed to study (167,167m) Ir. A reaction of Sn-112(Ni-58, p2n) at a beam energy of 266 MeV and target thickness 500 mu g cm(-2) was used to study (169,169m) Ir. The experiments were performed at the University of Jyvaskyla utilizing the RITU separator in conjunction with the focal plane GREAT spectrometer and the JUROGAM Ge array at the target position. Excited states feeding. both the ground state and isomeric state in Ir-169, excited states feeding the ground state of Ir-167 and the ground state alpha decay of Re-165 have been observed for the first time along with excited states feeding (167)m Ir Experimental spectroscopic factors and reduced widths have been obtained for the proton and alpha decay of these nuclei.
  •  
30.
  • Clément, E., et al. (författare)
  • Low-energy Coulomb excitation of Sr 96,98 beams
  • 2016
  • Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 94:5, s. 054326-
  • Tidskriftsartikel (refereegranskat)abstract
    • The structure of neutron-rich Sr96,98 nuclei was investigated by low-energy safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN, with the MINIBALL spectrometer. A rich set of transitional and diagonal E2 matrix elements, including those for non-yrast structures, has been extracted from the differential Coulomb-excitation cross sections. The results support the scenario of a shape transition at N=60, giving rise to the coexistence of a highly deformed prolate and a spherical configuration in Sr98, and are compared to predictions from several theoretical calculations. The experimental data suggest a significant contribution of the triaxal degree of freedom in the ground state of both isotopes. In addition, experimental information on low-lying states in Rb98 has been obtained.
  •  
31.
  • Clément, E, et al. (författare)
  • Spectroscopic Quadrupole Moments in ^{96,98}Sr: Evidence for Shape Coexistence in Neutron-Rich Strontium Isotopes at N=60.
  • 2016
  • Ingår i: Physical Review Letters. - 1079-7114. ; 116:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Neutron-rich ^{96,98}Sr isotopes have been investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross sections. These results allow, for the first time, the drawing of definite conclusions about the shape coexistence of highly deformed prolate and spherical configurations. In particular, a very small mixing between the coexisting states is observed, contrary to other mass regions where strong mixing is present. Experimental results have been compared to beyond-mean-field calculations using the Gogny D1S interaction in a five-dimensional collective Hamiltonian formalism, which reproduce the shape change at N=60.
  •  
32.
  • Drummond, M. C., et al. (författare)
  • Low-lying excited states in the neutron-deficient isotopes Os-163 and Os-165
  • 2013
  • Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 87:5, s. 054309-
  • Tidskriftsartikel (refereegranskat)abstract
    • Excited states in the neutron-deficient isotopes Os-163 and Os-165 were identified using the JUROGAM and GREAT spectrometers in conjunction with the RITU gas-filled separator. The Os-163 and Os-165 nuclei were populated via the Cd-106(Ni-60,3n) and Mo-92(Kr-78,2p3n) reactions at bombarding energies of 270 MeV and 357 MeV, respectively. Gamma-ray emissions from these nuclei have been established unambiguously using the recoil-decay tagging technique and a coincidence analysis has allowed level schemes to be established. These results suggest that the yrast states are based upon negative-parity configurations originating from the f(7/2) and h(9/2) orbitals.
  •  
33.
  • Joss, D. T., et al. (författare)
  • Discovery of the proton emitting nucleus 159Re
  • 2007
  • Ingår i: Proton Emitting Nuclei and Related Topics. - : American Institute of Physics (AIP). - 9780735404755 ; , s. 28-33
  • Konferensbidrag (refereegranskat)abstract
    • The observation of the new nuclide 159Re provides important insights into the evolution of single-particle structure in heavy nuclei beyond the proton drip line. The nuclide 159Re was synthesised in the reaction 106Cd(58Ni, p4n) and identified via its proton radioactivity using the RITU gas-filled separator and the GREAT focal-plane spectrometer. Comparisons of the measured proton energy (Ep = 1805±20 keV) and decay half-life (t1/2 = 21±4 μs) with values calculated using the WKB method indicate that the proton is emitted from an h11/2 state. The implications of these results for future experimental investigations into even more proton unbound Re isotopes using in-flight separation techniques are considered.
  •  
34.
  • Joss, D. T., et al. (författare)
  • Probing the limit of nuclear existence : Proton emission from Re-159
  • 2006
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 641:1, s. 34-37
  • Tidskriftsartikel (refereegranskat)abstract
    • The observation of the new nuclide Re-159(75)84 provides important insights into the evolution of single-particle structure and the mass surface in heavy nuclei beyond the proton drip line. This nuclide, 26 neutrons away from the nearest stable rhenium isotope, was synthesised in the reaction Cd-106(Ni-58, p4n) and identified via its proton radioactivity using the RITU gas-filled separator and the GREAT focal-plane spectrometer. Comparisons of the measured proton energy (E-p = 1805 +/- 20 keV) and decay half-life (t(1/2) = 21 +/- 4 mu s) with values calculated using the WKB method indicate that the proton is emitted from an h(11/2) state. The implications of these results for future experimental investigations into even more proton unbound nuclei using in-flight separation techniques are considered.
  •  
35.
  • Joss, D. T., et al. (författare)
  • Recoil decay tagging of gamma rays in the extremely neutron-deficient nucleus Os-162
  • 2004
  • Ingår i: Physical Review C. Nuclear Physics. - : American Physical Society. - 0556-2813 .- 1089-490X. ; 70:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The neutron-deficient nucleus Os-162, produced in the Cd-106(Ni-58,2n) reaction, has been studied using the JUROGAM gamma-ray spectrometer in conjunction with the RITU gas-filled separator and the GREAT focal plane spectrometer. gamma-ray transitions in Os-162 have been assigned for the first time through the application of the recoil decay tagging technique. The excitation energy of the 2(+) state and the tentative energy of the 8(+) state are discussed in terms of the systematic energy trends as the N=82 shell gap is approached.
  •  
36.
  • Joss, D. T., et al. (författare)
  • Yrast states and band crossings in the neutron-deficient platinum isotopes Pt169-173
  • 2006
  • Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 74:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The yrast states in the light platinum isotopes Pt169-173 have been investigated in a recoil-decay tagging experiment using the JUROGAM gamma-ray spectrometer in conjunction with the RITU gas-filled recoil separator and the GREAT tagging spectrometer. Gamma-ray transitions have been established for the first time in the odd-N isotopes, Pt-169 and Pt-173, and the yrast sequences in Pt-170 and Pt-172 have been extended. We discuss the possibility that the weakly deformed yrast structures of Pt-170, Pt-172, and Pt-173 are crossed by a deformed intruder configuration at spin similar to 8h.
  •  
37.
  • Lagergren, Karin, et al. (författare)
  • gamma-soft shapes and quasiparticle excitations in Ta-161(73)88
  • 2011
  • Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 83:1, s. 014313-
  • Tidskriftsartikel (refereegranskat)abstract
    • Excited states in the neutron-deficient odd-Z nuclide Ta-161 were identified for the first time using the Cd-106(Ni-58,3p gamma) reaction at a beam energy of 270 MeV. The pi h(11/2) 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 nu(f(7/2), h(9/2)) orbitals are responsible for the first rotational alignment in the pi h(11/2) band.
  •  
38.
  • Lagergren, Karin, et al. (författare)
  • High-spin states in the proton-unbound nucleus Re-161
  • 2006
  • Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 74:2, s. 024316-
  • Tidskriftsartikel (refereegranskat)abstract
    • Excited states in Re-161 were populated using the Cd-106(Ni-58, p2n) reaction at a beam energy of 270 MeV, resulting in the first observation of gamma rays emitted from this nucleus. The reaction products were separated from scattered beam and fission fragments by the gas-filled recoil separator RITU, and were implanted in the double-sided silicon strip detectors of the GREAT spectrometer. Prompt gamma rays were detected by the JUROGAM Ge detector array and were assigned to Re-161 based on alpha- and proton-decay tagging of the implanted reaction products. The near-yrast high-spin level structure, which was delineated to spins around 39/2, is discussed in the context of the total Routhian surface formalism. The level scheme is interpreted in terms of the alignment of h(9/2)/f(7/2) neutrons at lower spins, followed by excitations involving the pi h(11/2) subshell at higher spins.
  •  
39.
  • Morrison, L., et al. (författare)
  • Quadrupole and octupole collectivity in the semi-magic nucleus 20680Hg126
  • 2023
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 838
  • Tidskriftsartikel (refereegranskat)abstract
    • The first low-energy Coulomb-excitation measurement of the radioactive, semi-magic, two proton-hole nucleus 206Hg, was performed at CERN's recently-commissioned HIE-ISOLDE facility. Two γ rays depopulating low-lying states in 206Hg were observed. From the data, a reduced transition strength B(E2; 2+1 → 0+1) = 4.4(6) W.u. was determined, the first such value for an N=126 nucleus south of 208Pb, which is found to be slightly lower than that predicted by shell-model calculations. In addition, a collective octupole state was identified at an excitation energy of 2705 keV, for which a reduced B(E3) transition probability of 30+10-30 W.u. was extracted. These results are crucial for understanding both quadrupole and octupole collectivity in the vicinity of the heaviest doubly-magic nucleus 208Pb, and for benchmarking a number of theoretical approaches in this key region. This is of particular importance given the paucity of data on transition strengths in this region, which could be used, in principle, to test calculations relevant to the astrophysical r-process.
  •  
40.
  • Morrison, L., et al. (författare)
  • Quadrupole deformation of Xe 130 measured in a Coulomb-excitation experiment
  • 2020
  • Ingår i: Physical Review C. - 2469-9985. ; 102:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Low-lying states in the isotope Xe130 were populated in a Coulomb-excitation experiment performed at CERN's HIE-ISOLDE facility. The magnitudes and relative signs of seven E2 matrix elements and one M1 matrix element coupling five low-lying states in Xe130 were determined using the semiclassical coupled-channel Coulomb-excitation least-squares search code gosia. The diagonal E2 matrix elements of both the 21+ and 41+ states were extracted for the first time. The reduced transition strengths are in line with those obtained from previous measurements. Experimental results were compared with the general Bohr Hamiltonian with the microscopic input from mean-field theory utilizing universal nuclear energy density functional (UNEDF0), shell-model calculations using the GCN50:82 and SN100PN interactions, and simple phenomenological models (Davydov-Filippov and γ-soft). The extracted shape parameters indicate triaxial-prolate deformation in the ground-state band. In general, good agreement between theoretical predictions and experimental values was found, while neither phenomenological model was found to provide an adequate description of Xe130.
  •  
41.
  • Page, R. D., et al. (författare)
  • alpha decay of Re-159 and proton emission from Ta-155
  • 2007
  • Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 75:6, s. 061302-
  • Tidskriftsartikel (refereegranskat)abstract
    • The alpha decay of Re-159 has been observed for the first time in reactions of 300 MeV Ni-58 ions with an isotopically enriched Cd-106 target. The Re-159 ions were separated in-flight using the RITU separator and implanted into the GREAT spectrometer. The alpha decay emanates from the proton-emitting pi h(11/2) state in Re-159 with an energy of E-alpha=6776 +/- 26 keV and a branching ratio of 7.5 +/- 3.5%. This alpha decay populates a state in the closed neutron shell nucleus Ta-155, which decays by emitting 1444 +/- 15 keV protons with a half-life of 2.9(-1.1)(+1.5) ms. These values are consistent with the emission of the proton from a pi h(11/2) orbital. These results fit in with the systematics of proton and alpha-particle separation energies in the region, but disagree with the previously reported decay properties of Ta-155.
  •  
42.
  • Page, R. D., et al. (författare)
  • Probing single-particle structures beyond the proton drip line
  • 2007
  • Ingår i: Proton Emitting Nuclei and Related Topics. - : American Institute of Physics (AIP). - 9780735404755 ; , s. 137-142
  • Konferensbidrag (refereegranskat)abstract
    • Single-particle energies have been investigated in the closed neutron shell proton emitter 155Ta. The 155Ta nuclei were populated through the α decay of 159Re, which has been observed for the first time. The 159Re nuclei were produced in reactions of 300 MeV 58Ni ions with an isotopically enriched 106Cd target, separated in-flight using the RITU separator and implanted into the GREAT spectrometer. The 159Re α decay emanates from the proton-emitting πh11/2 state and populates a state in 155Ta which decays by the emission of a proton from a πh 11/2 orbital. The results fit in with the systematics of proton and α-particle separation energies in the region, but disagree with the previously reported decay properties of 155Ta.
  •  
43.
  • Parr, E., et al. (författare)
  • Identification of the J(pi)=1(-) state in Ra-218 populated via alpha decay of Th-222
  • 2016
  • Ingår i: PHYSICAL REVIEW C. - 2469-9985. ; 94:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The alpha decay of Th-222 populating the low-lying J(pi) = 3(-) state, and also a proposed 1(-) state, in Ra-218 has been observed. The observations suggest an excitation energy of 853 keV for the 1(-) state, which is 60 keV above the 3(-) state. The hindrance factors of these alpha decays give a possible boundary to the region of ground-state octupole deformation in the light-actinide nuclei. The relative positions of the J(pi) = 1(-) and 3(-) states suggest they are produced by an octupole-vibrational mechanism, as opposed to alpha clustering or rotations of a reflection-asymmetric octupole-deformed shape.
  •  
44.
  • Petrache, C. M., et al. (författare)
  • Evidence of chiral bands in even-even nuclei
  • 2018
  • Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 97:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Evidence for chiral doublet bands has been observed for the first time in the even-even nucleus Nd136. One chiral band was firmly established. Four other candidates for chiral bands were also identified, which can contribute to the realization of the multiple pairs of chiral doublet bands (MχD) phenomenon. The observed bands are investigated by the constrained and tilted axis cranking covariant density functional theory (TAC-CDFT). Possible configurations have been explored. The experimental energy spectra, angular momenta, and B(M1)/B(E2) values for the assigned configurations are globally reproduced by TAC-CDFT. Calculated results support the chiral interpretation of the observed bands, which correspond to shapes with maximum triaxiality induced by different multiquasiparticle configurations in Nd136.
  •  
45.
  • Seidlitz, M., et al. (författare)
  • Coulomb excitation of Na-29,Na-30: Mapping the borders of the island of inversion
  • 2014
  • Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 89:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Nuclear shell evolution in neutron-rich Na nuclei around N = 20 was studied by determining reduced transition probabilities, i.e., B(E2) and B(M1) values, in order to map the border of the island of inversion. To this end Coulomb-excitation experiments, employing radioactive Na-29,Na-30 beams with a final beam energy of 2.85 MeV/nucleon, were performed at REX-ISOLDE, CERN. De-excitation gamma rays were detected by the MINIBALL gamma-ray spectrometer in coincidence with scattered particles in a segmented Si detector. Transition probabilities to excited states were deduced. The measured B(E2) values agree well with shell-model predictions, supporting the idea that in the Na isotopic chain the ground-state wave function contains significant intruder admixture already at N = 18, with N = 19 having an almost pure two-particle-two-hole deformed ground-state configuration.
  •  
46.
  • Singh, B. S. Nara, et al. (författare)
  • Coulomb shifts and shape changes in the mass 70 region
  • 2007
  • Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 75:6
  • Tidskriftsartikel (refereegranskat)abstract
    • The technique of recoil beta tagging has been developed which allows prompt gamma decays in nuclei from excited states to be correlated with electrons from their subsequent short-lived beta decay. This technique is ideal for studying nuclei very far from stability and improves in sensitivity for very short-lived decays and for high decay Q-values. The method has allowed excited states in Y-78 to be observed for the first time, as well as an extension in the knowledge of T=1 states in Rb-74. From this new information it has been possible to compare Coulomb energy differences (CED) between T=1 states in Br-70/Se-70, Rb-74/Kr-74, and Y-78/Sr-78. The A=70 CED exhibit an anomalous behavior which is inconsistent with all other known CED. This behavior may be accounted for qualitatively in terms of small variations in the Coulomb energy arising from shape changes.
  •  
47.
  • Singh, B. S. Nara, et al. (författare)
  • Recoil Beta Tagging : Application to the study of odd-odd near proton drip line nuclei, Rb-74 and Y-78
  • 2007
  • Ingår i: The European Physical Journal Special Topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 150, s. 147-148
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a study of low-spin states in Rb-74 and Y-78 using the new technique of Recoil Beta Tagging. This yielded new information on Rb-74 and has provided the first evidence for non-isomeric T = 1 states in Y-78.
  •  
48.
  • Zhang, W., et al. (författare)
  • Decay spectroscopy of 171,172Os and 171,172,174Ir
  • 2023
  • Ingår i: Physical Review C. - : American Physical Society (APS). - 2469-9985 .- 2469-9993. ; 107:1
  • Tidskriftsartikel (refereegranskat)abstract
    • We report on a study of the α-decay fine structure and the associated Eα−Eγ correlations in the decays of 171,172Os and 171,172,174Ir. In total, 13 new α-decay energy lines have been resolved, and three new γ-ray transitions have been observed following the new decay branches to 168Re and 167W. The weak α-decay branch from the bandhead of the νi13/2 band in 171Os observed in this work highlights an unusual competition between α, β, and electromagnetic decays from this isomeric state. The nucleus 171Os is therefore one of few nuclei observed to exhibit three different decay modes from the same excited state. The nuclei of interest were produced in 92Mo(83Kr,xpyn) fusion-evaporation reactions at the Accelerator Laboratory of the University of Jyväskylä, Finland. The fusion products were selected using the gas-filled ion separator RITU and their decays were characterized using an array of detectors for charged particles and electromagnetic radiation known as GREAT. Prompt γ-ray transitions were detected and correlated with the decays using the JUROGAM II germanium detector array surrounding the target position. Results obtained from total Routhian surface (TRS) calculations suggest that α-decay fine structure and the associated hindrance factors may be a sensitive probe of even relatively small shape changes between the final states in the daughter nucleus.
  •  
49.
  • Ahlgren Cederlöf, Ebba, et al. (författare)
  • Lifetime measurement of the yrast 2+ state in 118Te
  • 2023
  • Ingår i: European Physical Journal A. - : Springer. - 1434-6001 .- 1434-601X. ; 59:12
  • Tidskriftsartikel (refereegranskat)abstract
    • The electromagnetic transition probabilities of the yrast 2+ states in the midshell Te isotopes, two protons above the closed shell at Sn, are of great importance for the understanding of nuclear collectivity in these isotopes and the role played by the neutron-proton interactions and cross-shell excitations. However, the large uncertainty of the experimental data for the midshell nucleus 118Te and the missing data for 116Te make it difficult to pin down the general trend of the evolution of transition probabilities as a function of the neutron number. In this work, the lifetime of the yrast 2+ state in 118Te was measured, with the aim of reducing the uncertainty of the previous measurement. The result is τ2+ = 7.46(19) ps. In addition, the lifetime of the 4+ state was measured to be τ4+ = 4.25(23) ps. The experimental transition rates are extracted from the measured lifetimes and compared with systematic large-scale shell-model calculations. The trend of the B(E2; 0+ → 2+) values in the midshell area is in good agreement with the calculations and the calculated B4/2 ratio provide evidence for 118Te as a near perfect harmonic vibrator.
  •  
50.
  • Badran, H., et al. (författare)
  • Confirmation of the new isotope Pb-178
  • 2016
  • Ingår i: PHYSICAL REVIEW C. - 2469-9985. ; 94:5
  • Tidskriftsartikel (refereegranskat)abstract
    • The extremely neutron-deficient isotope Pb-178 has been produced. The GREAT spectrometer at the focal plane position of the gas-filled separator RITU was used to study the alpha decay of Pb-178 and its alpha-decay chain through alpha-alpha correlations. The alpha decay was measured to have an energy and half-life of E-alpha = 7610(30) keV and t(1/2) = 0.21(-0.08)(+0.21) ms, respectively. The half-life is consistent with recent theoretical calculations using the Coulomb and proximity potential model. The alpha-decay reduced width and hindrance factor for Pb-178 were deduced and correspond to an unhindered Delta l = 0 transition. In addition, the mass excess of Pb-178 and the alpha-decay Q value were calculated from the experimental results and compared to theoretical values.
  •  
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