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  • 1.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Lifetime measurements of excited states in 165Lu and 107Cd2006Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Measuring lifetimes of excited nuclear states can give important information on the internal structure of the nucleus. This thesis is based on two experiments performed in Italy and in the USA in order to deduce the lifetimes of excited states in 165Lu and 107Cd. The lifetimes were measured using the Recoil Distance Method and the reduced transition probabilities between states have been calculated from the lifetimes in a model independent way. In the analysis of the data from the experiment on 165Lu, the shape of the nucleus is investigated using a collective rotational model to describe the observed excited states. A possibility of a triaxial shape of this nucleus is discussed. In the second experiment the obtained reduced transition probabilities for the nucleus 107Cd are compared to theoretical predictions for vibrational and rotational excitation modes

  • 2.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Studies of collective phenomena in neutron deficient nuclei: by means of lifetime measurements, angular correlation measurements and the recoil-decay tagging technique2008Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The nucleus is a mesoscopic system that retains features from both the quantum and macroscopic worlds. A basic property of a macroscopic body is its shape. Nuclear shapes can be deduced from experimental data as they influence the excitation mode of the nucleus and hence the energies and lifetimes of its excited levels. Various short-lived nuclei were created in fusion-evaporation experiments performed at international heavy-ion accelerator facilities. The emitted γ rays and, in some experiments, also the charged particles and neutrons emitted in the reactions were detected. The studied neutron-deficient isotopes were either selected by the type and number of particles emitted in the reactions, or by using their characteristic decays. The excited states of the different isotopes were extracted from the γ-ray analyses. Spectroscopic properties, such as the lifetimes of the excited states or the angular distribution of the emitted γ rays were measured when possible. The experimentally obtained level schemes together with the other spectroscopic information were used to deduce the excitation modes and the shapes of the studied nuclei. The detector systems are described in the first chapter and in the second chapter some techniques used to extract information from the experimental data are explained. Finally, a brief theoretical overview on the nuclear models which were used to interpret the experimental results is given.

  • 3.
    Andgren, Karin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Ashley, S. F.
    Regan, P. H.
    McCutchan, E. A.
    Zamfir, N. V.
    Amon, L.
    Cakirli, R. B.
    Casten, R. F.
    Clark, R. M.
    Erduran, M. N.
    Gurdal, G.
    Keyes, K. L.
    Meyer, D. A.
    Papenberg, A.
    Pietralla, N.
    Plettner, C.
    Rainovski, G.
    Ribas, R. V.
    Thomas, N. J.
    Vinson, J.
    Warner, D. D.
    Werner, V.
    Williams, E.
    Recoil distance method lifetime measurements in Cd-107 and Pd-101.2006Inngår i: Frontiers in Nuclear Structure Astrophysics, and Reactions: FINUSTAR / [ed] Harissopulos, S; Demetriou, P; Julin, R, MELVILLE, NY: AMER INST PHYSICS , 2006, Vol. 831, s. 391-393Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Preliminary lifetime values have been measured for a number of near-yrast states in the odd-A transitional nuclei Cd-107 and Pd-103. The reaction used to populate the nuclei of interest was Mo-98(C-12, 3nx alpha)Cd-107, Pd-103, with the beam delivered by the tandem accelerator of the Wright Nuclear Structure Laboratory at an incident beam energy of 60 MeV. Our experiment was aimed at the investigation of collective excitations built on the unnatural parity, v h(11/2) orbital, specifically by measuring the B(E2) values of decays from the excited levels built on this intrinsic structure, using the Doppler Recoil Distance Method. We report lifetimes and associated transition probabilities for decays from the 15/2(-) and the 19/2(-) states in Cd-107 and the first measurement of the 15/2- state in Pd-103. These results suggest that neither a simple rotational or vibrational interpretation is sufficient to explain the observed structures.

  • 4.
    Andgren, Karin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Ashley, Stephen
    Univ Surrey, Dept Phys.
    Regan, Patrick
    Univ Surrey, Dept Phys.
    McCutchan, Elizabeth
    Yale Univ, WNSL.
    Zamfir, Victor
    Yale Univ, WNSL.
    et al.,
    RDM lifetime measurements in 107Cd2005Inngår i: Journal of Physics G: Nuclear and Particle Physics, ISSN 0954-3899, E-ISSN 1361-6471, Vol. 31, nr 10, s. S1563-S1568Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lifetimes for decays linking near-yrast states in Cd-107 have been measured using the recoil distance method (RDM). The nucleus of interest was populated via the (MO)-M-98(C-12,3n)(107) Cd fusion-evaporation reaction at an incident beam energy of 60 MeV. From the measured lifetimes, transition probabilities have been deduced and compared with the theoretical B(E2) values for limiting cases of harmonic vibrational and axially deformed rotational systems. Our initial results suggest a rotor-like behaviour for the structure based on the unnatural-parity, h(11/2) orbital in Cd-107, providing further evidence for the role of this 'shape-polanzing' orbital in stabilizing the nuclear deformation in the A similar to 100 transitional region.

  • 5.
    Andgren, Karin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Bäck, Torbjörn
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Johnson, Arne
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Wyss, Ramon
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    gamma-ray spectroscopy of At-1972008Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 78, nr 4, s. 044328-1-044328-8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Excited states of the extremely neutron-deficient nucleus At-197 have been studied in an in-beam experiment using the fusion-evaporation reaction Sn-118(Kr-82,p2n)At-197. gamma rays belonging to At-197 feeding the I-pi=(9/2(-)) ground state, as well as gamma rays feeding the 311-keV I-pi=(13/2(+)) isomer, decaying via the emission of gamma rays, and the 52-keV I-pi=(1/2(+)) alpha-decaying isomer have been identified using the recoil-alpha-decay tagging technique. Total Routhian surface calculations predict a near-spherical shape for the (9/2(-)) ground state and oblate shapes with beta(2) around -0.2 for the (1/2(+)) and the (13/2(+)) states. These predictions agree with our experimental findings.

  • 6.
    Andgren, Karin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Johnson, Arne
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Wyss, Ramon
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    et al.,
    Excited states in the neutron-deficient nuclei Rn-197,Rn-199,Rn-2012008Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 77, nr 5, s. 054303-1-054303-7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Excited states of the extremely neutron-deficient radon isotopes with N = 111, 113, 115 have been studied for the first time in a series of in-beam experiments performed at the Accelerator Laboratory of the University of Jyvaskyla. The reactions used were: Sn-118(Kr-82, 3n)Rn-197, Sn-120(Kr-82, 3n)Rn-199, Sm-150(Cr-52, 3n)Rn-199, and Sn-122(Kr-82, 3n)Rn-201. The gamma rays emitted from excited states in the different isotopes were identified using the recoil-alpha-decay tagging technique. The estimated cross section for the production of Rn-197(m) was 7(3) nb, which is the lowest cross section reported so far for an in-beam study. The energies of the (17/2(+)) levels built on the isomeric (13/2(+)) states in Rn-197,Rn-199,Rn-201 indicate a transition from an anharmonic vibrational structure toward a rotational structure at low spins for these nuclei. However, the transition is not as sharp as predicted by theory.

  • 7.
    Andgren, Karin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Ganioglu, Ela
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Wyss, Ramon
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Johnson, Arne
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    et al.,
    Low-spin collective behavior in the transitional nuclei Mo-86,Mo-882007Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 76, nr 1, s. 014307-1-014307-9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Low-spin structures in Mo-86,Mo-88 were populated using the Ni-58(Ar-36, x alpha yp) heavy-ion fusion-evaporation reaction at a beam energy of 111 MeV. Charged particles and gamma rays were emitted in the reactions and detected by the DIAMANT CsI ball and the EXOGAM Ge array, respectively. In addition to the previously reported low-to-medium spin states in these nuclei, new low-spin structures were observed. Angular correlation and linear polarization measurements were performed in order to unambiguously determine the spins and parities of intensely populated states in Mo-88. Quasiparticle Random Phase Approximation (QRPA) calculations were performed for the first and second excited 2(+) states in Mo-86 and Mo-88. The results are in qualitative agreement with the experimental results, supporting a collective interpretation of the low-spin states for these transitional nuclei.

  • 8.
    Andgren, Karin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Podolyak, Zsolt
    Univ Surrey, Dept Phys.
    Dewald, Alfred
    Univ Cologne, Inst Kernphys.
    Xu, Fu-Rong
    Peking Univ, Sch Phys.
    Algora, Alejandro
    IFIC, Valencia.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    et al.,
    Lifetime measurements of normal deformed states in Lu-165(71)2005Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 71, nr 1, s. 121-127Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Picosecond lifetimes of medium spin states in Lu-165 were measured for the first time. The reaction used to populate the nucleus of interest was La-139(Si-30,4n)Lu-165 at a beam energy of 135 MeV. The beam was provided by the XTU-tandem accelerator of Laboratori Nazionali di Legnaro, Italy. By using the differential decay curve method, lifetimes of 19 states in four different rotational bands were obtained. Therefrom the B(E2) values and the transitional quadrupole moments were deduced. The obtained Q(t) for the different bands are compared with total Routhian surface (TRS) calculations and particle-rotor-model calculations. The TRS calculations predict different axial symmetric shapes for the bands built on the 9/2(-)[514], 9/2(+)[404], and 1/2(-)[541] configurations, with a gamma softness for the 9/2(-)[514] configuration. This band has also been studied using the particle-rotor model, the results of which, however, are consistent with a triaxial shape with a gamma value of -15(p).

  • 9. Ashley, S. F.
    et al.
    Linnemann, A.
    Jolie, J.
    Regan, P. H.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik. University of Surrey, United Kingdom .
    Dewald, A.
    McCutchan, E. A.
    Melon, B.
    Moeller, O.
    Zamfir, N. V.
    Amon, L.
    Boelaert, N.
    Cakirli, R. B.
    Casten, R. F.
    Clark, R. M.
    Fransen, C.
    Gelletly, W.
    Gurdal, G.
    Heidemann, M.
    Keyes, K. L.
    Erduran, M. N.
    Meyer, D. A.
    Papenberg, A.
    Plettner, C.
    Rainovski, G.
    Ribas, R. V.
    Thomas, Nathaniel J.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Vinson, J.
    Warner, D. D.
    Werner, V.
    Williams, E.
    Zell, K. O.
    Lifetime determination of excited states in Cd-1062007Inngår i: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 38, nr 4, s. 1385-1388Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Two separate experiments using the Differential Decay Curve Method have been performed to extract mean lifetimes of excited states in 106 Cd. The inedium-spin states of interest were populated by the Mo-98(C-12, 4n) Cd-106 reaction performed at the Wright Nuclear Structure Lab., Yale University. From this experiment, two isomeric state mean lifetimes have been deduced. The low-lying states were populated by the Mo-96(C-13, 3n)Cd-106 reaction performed at the Institut fur Kernphysik, Universitat zu Koln. The mean lifetime of the I-pi = 2(1)(+) state was deduced, tentatively, as 16.4(9) ps. This value differs from the previously accepted literature value from Coulomb excitation of 10.43(9) ps.

  • 10. Ashley, S. F.
    et al.
    Regan, P. H.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    McCutchan, E. A.
    Zamfir, N. V.
    Amon, L.
    Cakirli, R. B.
    Casten, R. F.
    Clark, R. M.
    Gelletly, W.
    Gürdal, G.
    Keyes, K. L.
    Meyer, D. A.
    Erduran, M. N.
    Papenberg, A.
    Pietralla, N.
    Plettner, C.
    Rainovski, G.
    Ribas, R. V.
    Thomas, N. J.
    Vinson, J.
    Warner, D. D.
    Werner, V.
    Williams, E.
    Liu, H. L.
    Xu, F. R.
    Intrinsic state lifetimes in Pd-103 and Cd-106,Cd-1072007Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 76, nr 6, s. 064302-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The mean-lifetimes, tau, of various medium-spin excited states in Pd-103 and Cd-106,Cd-107 have been deduced using the Recoil Distance Doppler Shift technique and the Differential Decay Curve Method. In Cd-106, the mean-lifetimes of the I-pi=12(+) state at E-x=5418 keV and the I-pi=11(-) state at E-x=4324 keV have been deduced as 11.4(17)ps and 8.2(7)ps, respectively. The associated beta(2) deformation within the axially-symmetric deformed rotor model for these states are 0.14(1) and 0.14(1), respectively. The beta(2) deformation of 0.14(1) for the I-pi=12(+) state in Cd-106 compares with a predicted beta(2) value from total Routhian surface (TRS) calculations of 0.17. In addition, the mean-lifetimes of the yrast I-pi = 15(-)/2 states in Pd-103 (at E-x=1262 keV) and Cd-107 (at E-x=1360 keV) have been deduced to be 31.2(44)ps and 31.4(17)ps, respectively, corresponding to beta(2) values of 0.16(1) and 0.12(1) assuming axial symmetry. Agreement with TRS calculations are good for Pd-103 but deviate for that predicted for Cd-107.

  • 11. Caceres, L.
    et al.
    Gorska, M.
    Jungclaus, A.
    Pfutzner, M.
    Grawe, H.
    Nowacki, F.
    Sieja, K.
    Pietri, S.
    Rudolph, D.
    Podolyak, Zs.
    Regan, P. H.
    Werner-Malento, E.
    Detistov, P.
    Lalkovski, S.
    Modamio, V.
    Walker, J.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Bednarczyk, P.
    Benlliure, J.
    Benzoni, G.
    Bruce, A. M.
    Casarejos, E.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Crespi, F. C. L.
    Doornenbal, P.
    Geissel, H.
    Gerl, J.
    Grebosz, J.
    Hadinia, Bahrak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Hellstrom, M.
    Hoischen, R.
    Ilie, G.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Kmiecik, M.
    Kojouharov, I.
    Kumar, R.
    Kurz, N.
    Maj, A.
    Mandal, S.
    Montes, F.
    Martinez-Pinedo, G.
    Myalski, S.
    Prokopowicz, W.
    Schaffner, H.
    Simpson, G. S.
    Steer, S. J.
    Tashenov, S.
    Wieland, O.
    Wollersheim, H. J.
    Spherical proton-neutron structure of isomeric states in Cd-1282009Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 79, nr 1, s. 011301-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The gamma-ray decay of isomeric states in the even-even nucleus Cd-128 has been observed. The nucleus of interest was produced both by the fragmentation of Xe-136 and the fission of U-238 primary beams. The level scheme was unambiguously constructed based on.. coincidence relations in conjunction with detailed lifetime analysis employed for the first time on this nucleus. Large-scale shell-model calculations, without consideration of excitations across the N = 82 shell closure, were performed and provide a consistent description of the experimental level scheme. The structure of the isomeric states and their decays exhibit coexistence of proton, neutron, and strongly mixed configurations due to p. interaction in overlapping orbitals for both proton and neutron holes.

  • 12. Carroll, R. J.
    et al.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Cederwal, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Doncel, Maria
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik. Department of Physics, University of Guelph, Guelph, ON, Canada.
    Jacobsson, Ulrika
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik. University of Jyväskylä, Department of Physics, Jyväskylä, Finland.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Taylor, M. J.
    Thornthwaite, A.
    et al.,
    Excited states in the proton-unbound nuclide Ta-1582016Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 93, nr 3, artikkel-id 034307Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Excited states in the neutron-deficient odd-odd proton-unbound nuclide Ta-158 have been investigated in two separate experiments. In the first experiment, Ir-166 nuclei were produced in the reactions of 380 MeV Kr-78 ions with an isotopically enriched Mo-92 target. The alpha-decay chain of the 9(+) state in Ir-166 was analyzed. Fine structure in the a decay of the 9(+) state in Re-162 established a 66 keV difference in excitation energy between the lowest-lying 9(+) and 10(+) states in Ta-158. Higher-lying states in Ta-158 were populated in the reactions of 255 MeV Ni-58 ions with an isotopically enriched Pd-102 target. Gamma-ray decay paths that populate, depopulate, and bypass a 19(-) isomeric state have been identified. The general features of the deduced level scheme are discussed and the prospects for observing proton emission branches from excited states are considered.

  • 13. Carroll, R. J.
    et al.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Qi, Chong
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Joss, D. T.
    Page, R. D.
    Uusitalo, J.
    Andgren, K.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Darby, I. G.
    Eeckhaudt, S.
    Grahn, T.
    Gray-Jones, C.
    Greenlees, P. T.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Leino, M.
    Leppanen, A. -P
    Nyman, M.
    Pakarinen, J.
    Rahkila, P.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Saren, J.
    Scholey, C.
    Seweryniak, D.
    Simpson, J.
    Multiparticle configurations of excited states in Lu-1552016Inngår i: PHYSICAL REVIEW C, ISSN 2469-9985, Vol. 94, nr 6, artikkel-id 064311Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Excited states in the neutron-deficient N = 84 nuclide Lu-155 have been populated by using the Pd-102(Ni-58, alpha p) reaction. The Lu-155 nuclei were separated by using the gas-filled recoil ion transport unit (RITU) separator and implanted into the Si detectors of the gamma recoil electron alpha tagging (GREAT) spectrometer. Prompt gamma-ray emissions measured at the target position using the JUROGAM Ge detector array were assigned to Lu-155 through correlations with alpha decays measured in GREAT. Structures feeding the (11/2(-)) and (25/2(-)) alpha-decaying states have been revised and extended. Shell-model calculations have been performed and are found to reproduce the excitation energies of several of the low-lying states observed to within an average of 71 keV. In particular, the seniority inversion of the 25/2(-) and 27/2(-) states is reproduced.

  • 14. Carroll, R. J.
    et al.
    Page, R. D.
    Joss, D. T.
    Uusitalo, J.
    Darby, I. G.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Eeckhaudt, S.
    Grahn, T.
    Gray-Jones, C.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Leino, M.
    Leppänen, A. -P
    Nyman, M.
    O'Donnell, D.
    Pakarinen, J.
    Rahkila, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Seweryniak, D.
    Simpson, J.
    Blurring the Boundaries: Decays of Multiparticle Isomers at the Proton Drip Line2014Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 112, nr 9, s. 092501-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A multiparticle spin-trap isomer has been discovered in the proton-unbound nucleus 158 73 Ta 85. The isomer mainly decays by (h) over bar -ray emission with a half-life of 6.1d(1) mu s. Analysis of the gamma-ray data shows that the isomer lies 2668 keV above the known 9(+) state and has a spin 10h higher and negative parity. This 19(-) isomer also has an 8644(11) keV, 1.4(2)% alpha-decay branch that populates the 9(+) state in Lu-154. No proton-decay branch from the isomer was identified, despite the isomer being unbound to proton emission by 3261(14) keV. This remarkable stability against proton emission is compared with theoretical predictions, and the implications for the extent of observable nuclides are considered.

  • 15. Carroll, R. J.
    et al.
    Page, R. D.
    Joss, D. T.
    Uusitalo, J.
    Darby, I. G.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Eeckhaudt, S.
    Grahn, T.
    Gray-Jones, C.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Leino, M.
    Leppänen, A. -P
    Nyman, M.
    O'Donnell, D.
    Pakarinen, J.
    Rahkila, P.
    Sandzelius, M.
    Sarén, J.
    Scholey, C.
    Seweryniak, D.
    Simpson, J.
    Competing decay modes of a high-spin isomer in the proton-unbound nucleus 158Ta2015Inngår i: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 46, nr 3, s. 695-698Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An isomeric state at high spin and excitation energy was recently observed in the proton-unbound nucleus 158Ta. This state was observed to decay by both α and γ decay modes. The large spin change required to decay via γ-ray emission incurs a lifetime long enough for α decay to compete. The α decay has an energy of 8644(11) keV, which is among the highest observed in the region, a partial half-life of 440(70) μs and changes the spin by 11h. In this paper, additional evidence supporting the assignment of this α decay to the high-spin isomer in 158Ta will be presented.

  • 16.
    Cederwall, Bo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Ghazi Moradi, Farnaz
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Bäck, Torbjörn
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Johnson, Arne
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Blomqvist, Jan-Erik
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Clément, E.
    Grand Accélérateur National d´lons Lourds, Cean Cedex, France.
    de France, G.
    Grand Accélérateur National d´lons Lourds, Cean Cedex, France.
    Wadsworth, R.
    Department of Physics, University of York, UK.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Lagergren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Dijon, A.
    Grand Accélérateur National d´lons Lourds, Cean Cedex, France.
    Jaworski, G.
    Heavy Ion Laboratory, Univeristy of Warsaw, Warsaw, Poland.
    Liotta, Roberto
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Qi, Chong
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Nyakó, B. M.
    Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary.
    Nyberg, J.
    Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.
    Palacz, M.
    Heavy Ion Laboratory, Univeristy of Warsaw, Warsaw, Poland.
    Al-Azri, H.
    Department of Physics, University of York, UK.
    Algora, A.
    IFIC, CSIC University of Valencia, Valencia, Spain.
    de Angelis, G.
    Instituto Nazionael di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, Italy.
    Atac, Ayse
    KTH, Skolan för teknikvetenskap (SCI).
    Bhattacharyya, S.
    Grand Accélérateur National d´lons Lourds, Cean Cedex, France.
    Brock, T.
    Department of Physics, University of York, York, UK.
    Brown, J. R.
    Department of Physics, University of York, York, UK.
    Davies, P.
    Department of Physics, University of York, York, UK.
    Di Nitto, A.
    Dipartimento di Scienze Fisiche, Universitá di Napoli and Instituto Nazionale di Fisica Nucleare, Napoli, Italy.
    Dombrádi, Zs.
    Institute of Nuclear Research of the Hungarian Academy of Science, Debrecen, Hungary.
    Gadea, A.
    IFIC, CSIC, University of Valencia, Valencia, Spain.
    Gál, J.
    Institute of Nuclear Research of the Hungarian Academy of Science, Debrecen, Hungary.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Johnston-Theasby, F.
    Department of Physics, University of York, York, UK.
    Joshi, P.
    Department of Physics, University of York, York, UK.
    Juhász, K.
    Department of Information Technology, Universty of Debrecen, Debrecen, Hungary.
    Julin, R.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Jungclaus, A.
    Instituto de Estructura de la Materia, Madrid, Spain .
    Kalinka, G.
    Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary.
    Kara, S. O.
    Department of Physics, Ankara University, Tandogan Ankarar, Turkey.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Kownacki, J.
    Heavy Ion Laboratory, Universty of Warsaw, Warsaw, Poland.
    La Rana, G.
    Dipartimento di Scienze Fisiche, Universitá di Napoli and Instituto Nazionale di Fisica Nucleare, Napoli, Italy.
    Lenzi, S. M.
    Dipartimento di Fisica dell'Universitá di Padova and Instituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova, Italy.
    Molnár, J.
    Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary.
    Moro, R.
    Dipartimento di Scienze Fisiche, Universitá di Napoli and Instituto Nazionale di Fisica Nucleare, Napoli, Italy.
    Napoli, D. R.
    Instituto Nazionale di Fisica Nucleare, Laboratori Natzionali di Legnaro, Legnaro, Italy.
    Nara Singh, B. S.
    Department of Physics, University of York, York, UK.
    Persson, Andreas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Recchia, F.
    Dipartimento di Fisica dell'Universitá di Padova and Instituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova, Italy.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Scheurer, J. -N
    Université Bordeaux, Centre d'Etudes Nucléaires de Bordeaux Gradignan, Gradignan, France.
    Sletten, G.
    The Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.
    Sohler, D.
    Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary.
    Söderström, P. -A
    Department of Physics and Astromony, Uppsala University, Uppsala, Sweden.
    Taylor, M. J.
    Department of Physics, University of York, York, UK.
    Timár, J.
    Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary.
    Valiente-Dobón, J. J.
    instituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, Italy.
    Vardaci, E.
    Dipartimento di Scienze Fisiche, Universitá di Napoli and Instituto Nazionale di Fisica Nucleare, Napoli, Italy.
    Williams, S.
    TRIUMF, Vancouver, British Columbia, Canada.
    Evidence for a spin-aligned neutron-proton paired phase from the level structure of 92Pd2011Inngår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 469, nr 7328, s. 68-71Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work(1) that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing(2-6), in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus Pd-92. Gamma rays emitted following the Ni-58(Ar-36,2n)Pd-92 fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution c-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction(2-6). We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling(7,8)) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis.

  • 17.
    Cederwall, Bo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Wyss, Ramon
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Evidence for enhanced collectivity in Te-I-Xe nuclei near the N=Z=50 double shell closure2007Inngår i: PROTON EMITTING NUCLEI AND RELATED TOPICS / [ed] Ferreira, LS; Arumugam, P, MELVILLE, USA: AMER INST PHYSICS , 2007, Vol. 961, s. 156-162Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Gamma-ray transitions have been identified for the first time in the extremely neutron-deficient T-z = 1 nuclide Xe-110 and the energies of the three lowest excited states in the ground-state band have been deduced. A level scheme has also been constructed for the proton-unbound, T-z = 3/2 nuclide I-109, exhibiting band structures built on g(7/2) and h(11/2) states in a weakly deformed, triaxial nucleus. In addition, a third band is proposed to be bui It oil a g(7/2) orbital coupled to an octupole-vibrational phonon of the Te-108 core. The results were obtained in a recoil-decay tagging experiment using the Ni-58(Fe-54,2n/p2n) reaction at a beam energy of 195 MeV. The experiment was performed using the highly efficient JUROGAM y-ray spectrometer in conjunction with the RITU gas-filled recoil separator and the GREAT focal -plane spectrometer. The results on Xe-110 establish a breaking of the normal trend of increasing first excited 2(+) and 4(+) level energies as a function of decreasing neutron number as the N = 50 major shell gap is approached for the neutron-deficient Xe isotopes. This unusual feature is suggested to be an effect of enhanced collectivity, possibly arising from isoscalar n-p interactions becoming increasingly important close to the N = Z line. Features in the low-lying levels of Te-106 and I-109, showing similar trends, are also discussed.

  • 18. Drummond, M. C.
    et al.
    Joss, D. T.
    Page, R. D.
    Simpson, J.
    O'Donnell, D.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Bianco, L.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Darby, I. G.
    Eeckhaudt, S.
    Gomez-Hornillos, M. B.
    Grahn, T.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Leppaenen, A. -P
    Leino, M.
    Nyman, M.
    Pakarinen, J.
    Rahkila, P.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Sapple, P. J.
    Saren, J.
    Saygi, B.
    Scholey, C.
    Sorri, J.
    Thomson, J.
    Uusitalo, J.
    Venhart, M.
    Low-lying excited states in the neutron-deficient isotopes Os-163 and Os-1652013Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 87, nr 5, s. 054309-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 19. Garnsworthy, A. B.
    et al.
    Thompson, N. J.
    Podolyak, Z.
    Walker, P. M.
    Williams, S. J.
    Dracoulis, G. D.
    de France, G.
    Lane, G. J.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Bruce, A. M.
    Byrne, A. P.
    Catford, W. N.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Jones, G. A.
    McGuirk, B.
    Mandal, S.
    Paul, E. S.
    Pucknell, V.
    Redon, N.
    Rosse, B.
    Senior, R. J.
    Sletten, G.
    Spectroscopy of Po-212 and At-213 using a He-8 radioactive beam and EXOGAM2005Inngår i: Journal of Physics G: Nuclear and Particle Physics, ISSN 0954-3899, E-ISSN 1361-6471, Vol. 31, nr 10, s. S1851-S1854Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A beam of 28 MeV He-8 particles with an average intensity 2 x 10(5) ions s(-1), produced by the SPIRAL facility at GANIL, was used to initiate fusion-evaporation reactions in thick targets of Pb-201 and Bi-209. Excited states of Po-212 and At-213 were populated in (He-8,4n) reactions. The emitted gamma-rays were detected using the EXOGAM array composed of four Compton suppressed germanium Clover detectors in a close geometry configuration. Preliminary results show that Po-212 has been populated to high spin (I similar or equal to 14) with a significantly increased yield compared with our previous He-8 beam experiment. An apparently increased relative population of states up to 12(+) was observed compared with published results from a Pb-208(Be-9,alpha n)(212) Po reaction at 48 MeV. Evidence is presented for a previously unreported de-excitation pathway: 69 keV (13(-) -> 12(+)). States up to I-pi = (39/2(-)) have also been observed in At-213.

  • 20.
    Ghazi Moradi, Farnaz
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Bäck, Torbjörn
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Atac, Ayse
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Johnson, Arne
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Qi, Chong
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Liotta, Roberto
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Wyss, Ramon
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Eeckhaudt, S.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Grahn, T.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Greenlees, P. T.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Jones, P. M.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Julin, R.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Juutinen, S.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Ketelhut, S.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Leino, M.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Nyman, M.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Rahkila, P.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Sarén, J.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Scholey, C.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Sorri, J.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Uusitalo, J.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Ganioglu, E.
    Science Faculty, Physics Department, Istanbul University, Istanbul, Turkey.
    Thomson, J.
    Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK.
    Joss, D. T.
    Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK.
    Page, R. D.
    Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK.
    Ertürk, S.
    CCLRC Daresbury Laboratory, Daresbury, Warrington, UK.
    Simpson, J.
    CCLRC Daresbury Laboratory, Daresbury, Warrington, UK.
    Gomez Hornillos, M. B.
    Seccio d'Enginyeria Nuclear, Universitat Politecnica de Catalunya, Barcelona, Spain.
    Bianco, L.
    Department of Physics, University of Guelph, Ontario, Canada.
    High-spin study of 162Ta2011Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 84, nr 6, s. 064312-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Excited states in the odd-odd neutron deficient nucleus (162)Ta (Z = 73, N = 89) have been studied for the first time. The gamma spectroscopy analysis using gamma - gamma - gamma coincidences revealed a strongly coupled rotational structure that was established up to large angular momentum states. The rotational band was assigned to the configuration pi h(11/2)[514]9/2 circle times nu i(13/2)[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 gamma-softminimum at beta(2) approximate to 0.16 and gamma approximate to 6 degrees. 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.

  • 21. Gorska, M.
    et al.
    Caceres, L.
    Grawe, H.
    Pfuetzner, M.
    Jungclaus, A.
    Pietri, S.
    Werner-Malento, E.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Evolution of the N=82 shell gap below Sn-132 inferred from core excited states in In-1312009Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 672, nr 4-5, s. 313-316Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The gamma-ray decay of ail excited state in In-131, the one proton hole neighbor of the doubly magic (132)sn has been measured. A high-spin, core-excited isomer with T-1/2 = 630(60) us was identified following production by both relativistic fragmentation of a Xe-136 beam and fission Of a U-238 beam. This state deexcites by a single gamma-ray branch of 3782(2) keV from which direct evidence for the size of the N = 82 shell gal) is inferred. The results are discussed in comparison to a shell-model Calculation including configurations across the closed shells at N = 82 and Z = 50.

  • 22. Grahn, T.
    et al.
    Stolze, S.
    Joss, D. T.
    Page, R. D.
    Saygi, B.
    O'Donnell, D.
    Akmali, M.
    Andgren, K.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Bianco, L.
    Cullen, D. M.
    Dewald, A.
    Greenlees, P. T.
    Heyde, K.
    Iwasaki, H.
    Jakobsson, U.
    Jones, P.
    Judson, D. S.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Leino, M.
    Lumley, N.
    Mason, P. J. R.
    Moeller, O.
    Nomura, K.
    Nyman, M.
    Petts, A.
    Peura, P.
    Pietralla, N.
    Pissulla, Th.
    Rahkila, P.
    Sapple, P. J.
    Saren, J.
    Scholey, C.
    Simpson, J.
    Sorri, J.
    Stevenson, P. D.
    Uusitalo, J.
    Watkins, H. V.
    Wood, J. L.
    Excited states and reduced transition probabilities in Os-1682016Inngår i: PHYSICAL REVIEW C, ISSN 2469-9985, Vol. 94, nr 4, artikkel-id 044327Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The level scheme of the neutron-deficient nuclide Os-168 has been extended and mean lifetimes of excited states have been measured by the recoil distance Doppler-shift method using the JUROGAM gamma-ray spectrometer in conjunction with the IKP Koln plunger device. The 168Os. rays were measured in delayed coincidence with recoiling fusion-evaporation residues detected at the focal plane of the RITU gas-filled separator. The ratio of reduced transition probabilities B(E2; 4(1)(+)-> 2(1)(+))/B(E2; 2(1)(+)-> 0(1)(+)) is measured to be 0.34(18), which is very unusual for collective band structures and cannot be reproduced by interacting boson model (IBM-2) calculations based on the SkM* energy-density functional.

  • 23.
    Hadinia, Baharak
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Blomqvist, Jan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Ganioglu, Ela
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Greenlees, P. T.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Darby, I. G.
    Eeckhaudt, S.
    Ideguchi, E.
    Jones, P. M.
    Joso, D. T.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Lagergren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Leppanen, A. -P
    Leino, M.
    Nyman, M.
    Pakarinen, J.
    Paul, E. S.
    Petri, M.
    Rahkila, P.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Saren, J.
    Scholey, C.
    Uusitalo, J.
    Wadsworth, R.
    First identification of gamma-rays in Te-106 using recoil decay tagging technique2006Inngår i: Frontiers in Nuclear Structure Astrophysics, and Reactions: FINUSTAR / [ed] Harissopulos, S; Demetriou, P; Julin, R, MELVILLE, NY: AMER INST PHYSICS , 2006, Vol. 831, s. 457-459Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Gamma-ray transitions from excited states in Te-106 have been identified using the recoil decay tagging technique. The experiment which was the reaction Fe-54(Fe-54,2n)Te-106* was performed at the JYFL accelerator facility at the University of Jyvaskyla, Finland. The production cross section was estimated at 25 nb, a new limit for in-beam gamma-ray spectroscopy. A tentative level structure for the ground state band of Te-106 is proposed.

  • 24.
    Hadinia, Baharak
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Blomqvist, Jan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Ganioğlu, Ela
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Greenlees, Paul
    Department of Physics, University of Jyväskylä.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Lagergren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Wyss, Ramon
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    et al.,
    First identification of excited states in 106Te and evidence for isoscalar-enhanced vibrational collectivity2005Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 72, nr 4, s. 041303-1-041303-5Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Gamma-ray transitions in the extremely neutron-deficient nucleus Te-106 have been identified for the first time. The experiment utilized the Fe-54(Fe-54,2n)Te-106(*) reaction, and the gamma-ray transitions from excited states in Te-106 were selected by use of the recoil-decay-tagging technique. The production cross section was estimated at 25 nb, a new limit for in-beam gamma-ray spectroscopy. A ground-state band tentatively extending up to I-pi=10(+) is proposed. The systematics of low-lying yrast states in the Te isotopes is discussed within the context of vibrational excitations and residual nucleon-nucleon interactions.

  • 25.
    Hadinia, Baharak
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Joss, Dave
    CCLRC, Daresbury Laboratory, Warrington.
    Wyss, Ramon
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Page, Robert
    Oliver Lodge Laboratory, Department of Physics, University of Liverpool.
    Johnson, Arne
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Lagergren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Ganioğlu, Ela
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Bäck, Torbjörn
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Liotta, Roberto
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    et al.,
    In-beam gamma-ray and alpha-decay spectroscopy of 170Ir2007Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 76, nr 4, s. 044312-1-044312-8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Excited states in the highly neutron deficient odd-odd nucleus Ir-170 have been investigated. The experiment was performed using the Sn-112(Ni-60, pn)Ir-170 reaction and employing the recoil-decay tagging technique. Gamma rays were detected using the JUROGAM gamma-ray spectrometer and those belonging to Ir-170 were selected based on recoil identification provided by the RITU gas-filled recoil separator and the GREAT spectrometer at the RITU focal plane. A partial level scheme of Ir-170 is presented for the first time. New alpha-decay branches are assigned to Ir-170 and a tentative level structure for Re-166 is deduced from a study of the alpha-decay fine structure and the associated alpha-gamma correlations.

  • 26.
    Hadinia, Baharak
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Page, R. D.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Scholey, C.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Bäck, Torbjörn
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Ganioglu, E.
    Hornillos, M. B. G.
    Grahn, T.
    Greenlees, P. T.
    Ideguchi, E.
    Jakobsson, U.
    Johnson, Arne
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Jones, P. M.
    Julin, R.
    Juutinen, J.
    Ketelhut, S.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Leino, M.
    Niikura, M.
    Nyman, M.
    Ozgur, I.
    Paul, E. S.
    Peura, P.
    Rahkila, P.
    Saren, J.
    Sorri, J.
    Uusitalo, J.
    Wyss, Ramon
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Identification of gamma rays from Au-172 and alpha decays of Au-172, Ir-168, and Re-1642009Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 80, nr 6, s. 064310-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The very neutron deficient odd-odd nucleus Au-172 was studied in reactions of 342 and 348 MeV Kr-78 beams with an isotopically enriched Ru-96 target. The alpha decays previously reported for Au-172 were confirmed and the decay chain extended down to Tm-152 through the discovery of a new alpha-decaying state in Re-164 [E-alpha=5623(10) keV; t(1/2)=864(-110)(+150) ms; b(alpha)=3(1)%]. Fine structure in these alpha decays of Au-172 and Ir-168 were identified. A new alpha-decaying state was also observed and assigned as the ground state in Au-172 [E-alpha=6762(10) keV; t(1/2)=22(-5)(+6) ms]. This decay chain was also correlated down to Tm-152 through previously reported alpha decays. Prompt gamma rays from excited states in Au-172 have been identified using the recoil-decay tagging technique. The partial level scheme constructed for Au-172 indicates that it has an irregular structure. Possible configurations of the alpha-decaying states in Au-172 are discussed in terms of the systematics of nuclei in this region and total Routhian surface calculations.

  • 27. Jakobsson, U.
    et al.
    Uusitalo, J.
    Juutinen, S.
    Leino, M.
    Nieminen, P.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Jones, P.
    Julin, R.
    Ketelhut, S.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Nyman, M.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Prompt and delayed spectroscopy of At-1992010Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 82, nr 4, s. 044302-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The neutron-deficient nucleus At-199 has been studied through gamma-ray and electron spectroscopy, using the recoil-decay tagging technique. Two experiments were conducted, using a gas-filled recoil separator with a focal-plane spectrometer alone and together with a germanium-detector array at the target position. The resulting level scheme for 199At includes a new isomer with a half-life of 0.80(5) mu s and a spin and parity of (29/2(+)). The 13/2(+) isomer, which de-excites via an M2 transition to the 9/2 ground state, was measured to have a half-life of 70(20) ns. Our earlier version of the level scheme for At-197 has been updated as well.

  • 28. Joss, D. T.
    et al.
    Page, R. D.
    Herzán, A.
    Donosa, L.
    Uusitalo, J.
    Carroll, R. J.
    Darby, I. G.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Eeckhaudt, S.
    Grahn, T.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Jakobsson, Ulrika
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik. University of Jyvaskyla, Finland.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Leino, M.
    Leppanen, A. -P
    Nyman, M.
    O'Donnell, D.
    Pakarinen, J.
    Rahkila, P.
    Sandzelius, M.
    Sarén, J.
    Scholey, C.
    Seweryniak, D.
    Simpson, J.
    Sorri, J.
    Spectroscopy at the two-proton drip line: Excited states in 158W2017Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 772, s. 703-707Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Excited states have been identified in the heaviest known even-Z N=84 isotone 158W, which lies in a region of one-proton emitters and the two-proton drip line. The observation of γ-ray transitions feeding the ground state establishes the excitation energy of the yrast 6+ state confirming the spin-gap nature of the α-decaying 8+ isomer. The 8+ isomer is also expected to be unbound to two-proton emission but no evidence for this decay mode was observed. An upper limit for the two-proton decay branch has been deduced as b2p≤ 0.17% at the 90% confidence level. The possibility of observing two-proton emission from multiparticle isomers in nearby nuclides is considered.

  • 29. Lalkovski, S.
    et al.
    Bruce, A. M.
    Jungclaus, A.
    Gorska, M.
    Pfuetzner, M.
    Caceres, L.
    Naqvi, F.
    Pietri, S.
    Podolyak, Zs.
    Simpson, G. S.
    Andgren, Karin
    KTH.
    Bednarczyk, P.
    Beck, T.
    Benlliure, J.
    Benzoni, G.
    Casarejos, E.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Crespi, F. C. L.
    Cuenca-Garcia, J. J.
    Cullen, I. J.
    Bacelar, A. M. Denis
    Detistov, P.
    Doornenbal, P.
    Farrelly, G. F.
    Garnsworthy, A. B.
    Geissel, H.
    Gelletly, W.
    Gerl, J.
    Grebosz, J.
    Hadinia, Baharak
    KTH.
    Hellström, M.
    Hinke, C.
    Hoischen, R.
    Ilie, G.
    Jaworski, G.
    Jolie, J.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Kisyov, S.
    Kmiecik, M.
    Kojouharov, I.
    Kumar, R.
    Kurz, N.
    Maj, A.
    Mandal, S.
    Modamio, V.
    Montes, F.
    Myalski, S.
    Palacz, M.
    Prokopowicz, W.
    Reiter, P.
    Regan, P. H.
    Rudolph, D.
    Schaffner, H.
    Sohler, D.
    Steer, S. J.
    Tashenov, S.
    Walker, J.
    Walker, P. M.
    Weick, H.
    Werner-Malento, E.
    Wieland, O.
    Wollersheim, H. J.
    Zhekova, M.
    Core-coupled states and split proton-neutron quasiparticle multiplets in Ag122-1262013Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 87, nr 3, s. 034308-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Neutron-rich silver isotopes were populated in the fragmentation of a Xe-136 beam and the relativistic fission of U-238. The fragments were mass analyzed with the GSI Fragment Separator and subsequently implanted into a passive stopper. Isomeric transitions were detected by 105 high-purity germanium detectors. Eight isomeric states were observed in Ag122-126 nuclei. The level schemes of Ag-122,Ag-123,Ag-125 were revised and extended with isomeric transitions being observed for the first time. The excited states in the odd-mass silver isotopes are interpreted as core-coupled states. The isomeric states in the even-mass silver isotopes are discussed in the framework of the proton-neutron split multiplets. The results of shell-model calculations, performed for the most neutron-rich silver nuclei are compared to the experimental data.

  • 30. Naqvi, F.
    et al.
    Gorska, M.
    Caceres, L.
    Jungclaus, A.
    Pfuetzner, M.
    Grawe, H.
    Nowacki, F.
    Sieja, K.
    Pietri, S.
    Werner-Malento, E.
    Regan, P. H.
    Rudolf, D.
    Podolyak, Z.
    Jolie, J.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Beck, T.
    Bednarczyk, P.
    Benlliure, J.
    Benzoni, G.
    Bruce, A. M.
    Casarejos, E.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Crespi, F. C. L.
    Detistov, P.
    Dombradi, Zs.
    Doornenbal, P.
    Geissel, H.
    Gerl, J.
    Grebosz, J.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Hellstrom, M.
    Hoischen, R.
    Ilie, G.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Kojouharov, I.
    Kmiecik, M.
    Kurz, N.
    Lalkovski, S.
    Maj, A.
    Mandal, S.
    Modamio, V.
    Montes, F.
    Myalski, S.
    Prokopowicz, W.
    Reiter, P.
    Schaffner, H.
    Simpson, G.
    Sohler, D.
    Steer, S. J.
    Tashenov, S.
    Walker, J.
    Wieland, O.
    Wollersheim, H. J.
    Isomer spectroscopy of (127)Cd2010Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 82, nr 3, s. 034323-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The spin and configurational structure of excited states of (127)Cd, the two-proton and three-neutron hole neighbor of (132)Sn, has been studied. An isomeric state with a half-life of 17.5(3) mu s was populated in the fragmentation of a (136)Xe beam on a (9)Be target at a beam energy of 750 MeV/u. Time distributions of the delayed gamma transitions and gamma gamma coincidence relations were exploited to construct a decay scheme. The observed yrast (19/2)(+) isomer is proposed to have dominant configurations of nu(h(11/2)(-3))pi(g(9/2)(-1), p(1/2)(-1)), nu(h(11/2)(-2)d(3/2)(-1))pi(g(9/2)(-2)), and nu(h(11/2)(-2), s(1/2)(-1))pi(g(9/2)(-2)) and to decay by two competing stretched M2 and E3 transitions. Experimental results are compared with the isotone (129)Sn. The new information provides input for the proton-neutron interaction and the evolution of neutron hole energies in nuclei around the doubly magic (132)Sn core.

  • 31. O'Donnell, D.
    et al.
    Grahn, T.
    Joss, D. T.
    Simpson, J.
    Scholey, C.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Bianco, L.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Ganioglu, Ela
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Sandzelius, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Spectroscopy of the neutron-deficient nucleus Os-167(91)2009Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 79, nr 6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Excited states of the nucleus Os-167 have been populated by the reaction Mo-92(Kr-78,2pn). The JUROGAM gamma-ray detector array has been used in conjunction with the RITU gas-filled separator and the GREAT spectrometer to observe prompt gamma rays in coincidence with recoiling fusion-evaporation residues and their subsequent decay by alpha particle emission. By correlating prompt gamma radiation with the characteristic alpha radioactivity of Os-167, it has been possible to extend the level scheme for this nucleus significantly. In particular, an extension of the yrast band and four previously unobserved bands are reported. In addition, the recoil distance Doppler-shift method was used to determine a lifetime of tau=20(4) ps for The I-pi=17/2(+) state in Os-167. Hence, the level of collectivity and magnitude of deformation of the low spin yrast band of this nucleus is established.

    .

     

  • 32. Pietri, S.
    et al.
    Jungclaus, A.
    Gorska, M.
    Grawe, H.
    Pfuetzner, M.
    Caceres, L.
    Detistov, P.
    Lalkovski, S.
    Modamio, V.
    Podolyak, Z.
    Regan, P. H.
    Rudolph, D.
    Walker, J.
    Werner-Malento, E.
    Bednarczyk, P.
    Doornenbal, P.
    Geissel, H.
    Gerl, J.
    Grebosz, J.
    Kojouharov, I.
    Kurz, N.
    Prokopowicz, W.
    Schaffner, H.
    Wollersheim, H. J.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Benlliure, J.
    Benzoni, G.
    Bruce, A. M.
    Casarejos, E.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Crespi, F. C. L.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Hellström, M.
    Hoischen, R.
    Ilie, G.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Kmiecik, M.
    Kumar, R.
    Maj, A.
    Mandal, S.
    Montes, F.
    Myalski, S.
    Simpson, G.
    Steer, S. J.
    Tashenov, S.
    Wieland, O.
    First observation of the decay of a 15(-) seniority v=4 isomer in Sn-1282011Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 83, nr 4, s. 044328-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Isomeric states in the semimagic Sn128-130 isotopes were populated in the fragmentation of a Xe-136 beam on a Be-9 target at an energy of 750 A.MeV. The decay of an isomeric state in Sn-128 at an excitation energy of 4098 keV has been observed. Its half live has been determined to be T-1/2 = 220(30) ns from the time distributions of the delayed gamma rays emitted in its decay. gamma gamma coincidence relations were analyzed in order to establish the decay pattern of the newly established state toward the known (7(-)) and (10(+)) isomers at excitation energies of 2092 and 2492 keV, respectively. Based on a comparison with results of state-of-the-art shell-model calculations the new isomeric state is proposed to have the nu h(11/2)(-3)d(3/2)(-1) configuration with the four neutron holes in Sn-132 maximally aligned to a total spin of I-pi = 15(-).

  • 33. Regan, P H
    et al.
    Wheldon, C
    Yamamoto, A D
    Valiente-Dobon, J J
    Cline, D
    Wu, C Y
    Macchiavelli, A O
    Xu, F R
    Smith, J F
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Chakrawarthy, R S
    Cromaz, M
    Fallon, P
    Freeman, S J
    Gorgen, A
    Hayes, A
    Hua, H
    Langdown, S D
    Lee, I Y
    Pearson, C J
    Podolyak, Z
    Teng, R
    Vibrational and rotational sequences in Mo-101 and Ru-103,Ru-4 studied via multinucleon transfer reactions2005Inngår i: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 36, nr 4, s. 1313-1322Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The near-yrast states of Mo-101(42)59 and Ru-103,4(44)59,60 have been studied following their population via heavy-ion multinucleon transfer reactions between a Xe-136 beam and a thin, self-supporting Mo-100 target. The ground state sequence in Ru-104 can be understood as demonstrating a simple evolution from a quasi-vibrational structure at lower spins to statically deformed, quasi-rotational excitation involving the population of a pair of low-Omega h(11/2) neutron orbitals. The effect of the decoupled h(11/2) orbital on this vibration-to-rotational evolution is demonstrated by an extension of the "E-GOS" prescription to include odd-A nuclei. The experimental results are also compared with self-consistent Total Routhian Surface calculations which also highlight the polarising role of the highly aligned neutron h(11/2) orbital in these nuclei.

  • 34.
    Sandzelius, Mikael
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Cedervall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Ganioglu, Ela
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Bäck, Torbjörn
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Johnson, Arne
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Wyss, Ramon
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    (gamma)-ray spectroscopy of 163Ta2009Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 80, nr 5, s. 054316-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Excited states in Ta-163 have been identified for the first time using the Cd-106(Ni-60,3p) fusion evaporation reaction. gamma rays were detected using the JUROGAM gamma-ray spectrometer and recoil discrimination was achieved using the recoil ion transport unit (RITU) gas-filled separator in conjunction with the GREAT spectrometer situated at the focal plane of the RITU. The yrast states are assigned to a strongly coupled rotational band based on a pi h(11/2) configuration. This structure exhibits large signature splitting at low spins that disappears after the paired band crossing because of the alignment of a pair of i(13/2) neutrons. This effect is ascribed to triaxial shape changes induced by the core-polarizing properties of the deformation-aligned h(11/2) proton and the rotation-aligned i(13/2) neutrons. Two additional strongly coupled band structures have been established and are discussed in terms of octupole-vibrational and two-quasiparticle excitations built on the yrast structure. The experimental results are compared with predictions from cranked-shell-model and total-Routhian-surface calculations.

  • 35.
    Sandzelius, Mikael
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Ganioǧlu, Ela
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Bäck, Torbjörn
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Grahn, T.
    Greenlees, P. T.
    Jakobsson, U.
    Johnson, Arne S.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Leino, M.
    Nyman, M.
    Peura, P.
    Rahkila, P.
    Sánre, J.
    Scholey, C.
    Sorri, J.
    Uusitalo, J.
    Wyss, Ramon A.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Probing the collective degrees of freedom at the proton drip line in the extremely neutron deficient 172Hg2011Inngår i: AIP Conf. Proc., 2011, s. 29-34Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Excited states in the extremely neutron-deficient isotope 172Hg have been established for the first time. The 96Ru( 78Kr,2n) reaction was employed to populate excited states in 172Hg with a cross section σ ≈ 15 nb. The highly selective Recoil-Decay Tagging (RDT) technique was used to obtain clean in-beam γ-ray spectra for 172Hg. The yrast ground-state band has tentatively been established up to I=6h̄. The data have been interpreted within the framework of total Routhian surface and quasiparticle random phase approximation calculations. In addition to the well-known features of shape coexistence previously observed in light Hg isotopes, the systematic trends in the energy of the yrast 2 + and 4 + states in the chain of Hg isotopes indicate a pronounced vibrational collectivity which is reduced in strength, but at the same time shows a higher degree of harmonicity, as the neutron number decreases below the neutron midshell.

  • 36.
    Sandzelius, Mikael
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Ganioglu, Ela
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Hadinia, Bahrak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Bäck, Torbjörn
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Johnson, Arne
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Wyss, Ramon
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    First observation of excited states in Hg-1722009Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 79, nr 6, s. 064315-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Excited states in the extremely neutron-deficient isotope Hg-172 have been established for the first time. The Ru-96(Kr-78,2n) reaction was employed to populate excited states in Hg-172 with a cross section sigma approximate to 15 nb. The highly selective recoil-decay tagging (RDT) technique was used to obtain clean in-beam gamma-ray spectra for Hg-172. The yrast ground-state band has tentatively been established up to I=6 h. The data have been interpreted within the framework of total Routhian surface and quasiparticle random phase approximation calculations.

    .

     

  • 37.
    Sandzelius, Mikael
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Wyss, Ramon A
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Indentification of Excited States in the Tz=1 Nucleus 110Xe: Evidence for Enhanced Collectivity Near the N=Z=50 Double Shell Closure2007Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 99, s. 022501-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Gamma-ray transitions have been identified for the first time in the extremely neutron-deficient (N=Z+2) nucleus Xe110, and the energies of the three lowest excited states in the ground-state band have been deduced. The results establish a breaking of the normal trend of increasing first excited 2+ and 4+ level energies as a function of the decreasing neutron number as the N=50 major shell gap is approached for the neutron-deficient Xe isotopes. This unusual feature is suggested to be an effect of enhanced collectivity, possibly arising from isoscalar n-p interactions becoming increasingly important close to the N=Z line.

  • 38.
    Sandzelius, Mikael
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Scholey, Catherine
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Ganioglu, Ela
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Bäck, Torbjörn
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Johnson, Arne
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Lagergren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Wyss, Ramon
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    First identification of excited states in 169Ir2007Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 75, nr 5, s. 054321-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Gamma rays populating the alpha-decaying isomeric state in Ir-169 have been observed for the first time. The experiment employed the recoil-decay tagging method using the JUROGAM gamma-ray spectrometer, the RITU gas-filled recoil separator and the GREAT spectrometer located at the RITU focal plane. The gamma-ray cascade feeding the isomeric alpha-decaying state exhibits a rotational structure consistent with a h(11/2) proton coupled to a triaxially deformed core. The experimental results are compared with predictions from total Routhian surface calculations.

  • 39. Scholey, C.
    et al.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Bianco, L.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Darby, I. G.
    et al,
    Isomeric and ground-state properties of Pt-171(78), Os-167(76), and W-163(74)2010Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 81, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Decay paths, half-lives, and excitation energies of the i(13/2) bandheads of the neutron-deficient nuclei Pt-171, Os-167, and W-163 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 nu f(7/2), nu h(9/2), and nu i(13/2) quasineutron states for all three nuclei. Moreover, ground-state spin assignments have been made for the first time, along with the measurement of the alpha-decay branching ratio for Pt-171. The decay paths of the i(13/2) bandheads were followed by favored alpha decays, indicating that all three nuclei have the same I-pi = 7/2(-) ground state.

1 - 39 of 39
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