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  • 101. Jeppesen, H. B.
    et al.
    Dragojevic, I.
    Clark, R. M.
    Gregorich, K. E.
    Ali, M. N.
    Allmond, J. M.
    Beausang, C. W.
    Bleuel, D. L.
    Cromaz, M.
    Deleplanque, M. A.
    Ellison, P. A.
    Fallon, P.
    Garcia, M. A.
    Gates, J. M.
    Greene, J. P.
    Gros, S.
    Lee, I. Y.
    Liu, H. L.
    Macchiavelli, A. O.
    Nelson, S. L.
    Nitsche, H.
    Pavan, J. R.
    Stavsetra, L.
    Stephens, F. S.
    Wiedeking, M.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Xu, F. R.
    Multi-quasiparticle states in (256)Rf2009In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 79, no 3, p. 031303-Article in journal (Refereed)
    Abstract [en]

    Excited states in (256)Rf were populated via the Pb-208(Ti-50,2n) fusion-evaporation reaction. Delayed gamma-ray and electron decay spectroscopy was performed and three isomeric states in (256)Rf have been identified. A fourth low-energy nonyrast state was identified from the gamma-ray decay of one of the higher lying isomers. The states are interpreted as multi-quasiparticle excitations.

  • 102.
    Jiang, Haowei
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Pan, F.
    Zhao, Y. M.
    Arima, A.
    Number of spin-I states for three identical particles in a single-j shell2013In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 87, no 3, p. 034313-Article in journal (Refereed)
    Abstract [en]

    In this paper we derive the analytical formulas of the number of spin-I states (denoted as D-I) for three identical particles, in a unified form for both fermions and bosons. This is done by using (n) over bar virtual bosons with spin 3/2, where (n) over bar equals 2j - 2 if one studies fermions in a single-j shell or 2l if one studies bosons with spin l. We first obtain a reduction rule from U(4) to O(3) for such virtual bosons and thereby derive the formulas of D-I. The formulas thus obtained are proved to be consistent with previous empirical formulas.

  • 103.
    Jiang, Hui
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Lei, Y.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Zhao, Y. M.
    Magnetic moments of low-lying states in tin isotopes within the nucleon-pair approximation2014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 89, no 1, p. 014320-Article in journal (Refereed)
    Abstract [en]

    The magnetic moments of the first excited 2(+) state in even-even nuclei Sn102-130 and the low-lying yrast states in odd-mass nuclei Sn-101-109,Sn-123-131 are calculated within the framework of the nucleon-pair approximation (NPA) of the shell model, by using the standard multipole-multipole interaction. Our calculations agree reasonably well with available experimental data. The g(2(1)(+)) values, as well as the contributions from their spin and orbital angular momentum components, are evaluated in terms of the small NPA subspace spanned by S and D nucleon pairs. The magnetic moment is suggested to be a sensitive probe of the nuclear wave function in this region.

  • 104.
    Jiang, Hui
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Lei, Y.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Zhao, Y. M.
    Nucleon pair approximation description of the low-lying structure of Te-108,Te-109 and I-1092013In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 88, no 4, p. 044332-Article in journal (Refereed)
    Abstract [en]

    The low-lying level schemes and electromagnetic transitions of Te-109, I-109, and the neighboring even-even nucleus Te-108 are calculated within the framework of the SD-pair approximation of the nuclear shell model. Good agreement is obtained between the calculated results and experimental data. The favored components of low-lying bands are discussed in the collective nucleon-pair subspace. The weak-coupling picture shown in these nuclei and its relationship with residual quadrupole-quadrupole interaction between valence protons and neutrons are analyzed.

  • 105. Jiao, L. F.
    et al.
    Sun, Z. H.
    Xu, Z. X.
    Xu, F. R.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Correlated-basis method for shell-model calculations2014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 90, no 2, p. 024306-Article in journal (Refereed)
    Abstract [en]

    We present a basis selection method for truncated shell-model calculations. In this method, the correlated basis is constructed with the eigenvectors of the Hamiltonian that is diagonalized in each partition of the shell model. A truncation scheme is established by naturally taking the low-lying correlated-basis vectors in different partitions, which is equivalent to the jj-coupling scheme of the shell model when all the correlated-basis vectors are considered. The results are compared with standard shell-model calculations. The convergence properties of the correlated-basis method are discussed.

  • 106.
    Johansson, C.
    et al.
    Department of Neutron Research, Uppsala University, Box 525, S-75120 Uppsala, Sweden.
    Blomgren, J.
    Department of Neutron Research, Uppsala University, Box 525, S-75120 Uppsala, Sweden.
    Ataç, Ayşe
    Department of Neutron Research, Uppsala University, Box 525, S-75120 Uppsala, Sweden.
    Bergenwall, B.
    Department of Neutron Research, Uppsala University, Box 525, S-75120 Uppsala, Sweden.
    Dangtip, S.
    Elmgren, K.
    Hildebrand, A.
    Jonsson, O.
    Klug, J.
    Mermod, P.
    Nadel-Turonski, P.
    Nilsson, L.
    Olsson, N.
    Pomp, S.
    Prokofiev, A. V.
    Renberg, P. U.
    Tippawan, U.
    Österlund, M.
    Forward-angle neutron-proton scattering at 96 MeV.2005In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 71Article in journal (Refereed)
  • 107. John, P. R.
    et al.
    Modamio, V.
    Valiente-Dobon, J. J.
    Mengoni, D.
    Lunardi, S.
    Rodriguez, T. R.
    Bazzacco, D.
    Gadea, A.
    Wheldon, C.
    Alexander, T.
    de Angelis, G.
    Ashwood, N.
    Barr, M.
    Benzoni, G.
    Birkenbach, B.
    Bizzeti, P. G.
    Bizzeti-Sona, A. M.
    Bottoni, S.
    Bowry, M.
    Bracco, A.
    Browne, F.
    Bunce, M.
    Camera, F.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Corradi, L.
    Crespi, F. C. L.
    Desesquelles, P.
    Eberth, J.
    Farnea, E.
    Fioretto, E.
    Goergen, A.
    Gottardo, A.
    Grebosz, J.
    Grente, L.
    Hess, H.
    Jungclaus, A.
    Kokalova, Tz.
    Korichi, A.
    Korten, W.
    Kusoglu, A.
    Lenzi, S.
    Leoni, S.
    Ljungvall, J.
    Maron, G.
    Meczynski, W.
    Melon, B.
    Menegazzo, R.
    Michelagnoli, C.
    Mijatovic, T.
    Million, B.
    Molini, P.
    Montagnoli, G.
    Montanari, D.
    Napoli, D. R.
    Nolan, P.
    Oziol, Ch.
    Podolyak, Zs.
    Pollarolo, G.
    Pullia, A.
    Quintana, B.
    Recchia, F.
    Reiter, P.
    Roberts, O. J.
    Rosso, D.
    Sahin, E.
    Salsac, M. -D
    Scarlassara, F.
    Sferrazza, M.
    Simpson, J.
    Soderstrom, P. -A
    Stefanini, A. M.
    Stezowski, O.
    Szilner, S.
    Theisen, Ch.
    Ur, C. A.
    Walshe, J.
    Shape evolution in the neutron-rich osmium isotopes: Prompt gamma-ray spectroscopy of Os-1962014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 90, no 2, p. 021301-Article in journal (Refereed)
    Abstract [en]

    The shape transition in the neutron-rich Os isotopes is studied by investigating the neutron-rich Os-196 nucleus through in-beam gamma-ray spectroscopy using a two-proton transfer reaction from a Pt-198 target to a Se-82 beam. The beam-like recoils were detected and identified with the large-acceptance magnetic spectrometer PRISMA, and the coincident gamma rays were measured with the advanced gamma tracking array (AGATA) demonstrator. The de-excitation of the low-lying levels of the yrast-band of Os-196 were identified for the first time. The results are compared with state-of-the-art beyond-mean-field calculations, performed for the even-even Os188-198 isotopes. The new results suggest a smooth transition in the Os isotopes from a more axial rotational behavior towards predominately vibrational nuclei through triaxial configurations. An almost perfect gamma-unstable/triaxial rotor yrast band is predicted for Os-196 which is in agreement with the experimentally measured excited states.

  • 108. Joss, D. T.
    et al.
    Lagergren, Karin
    KTH, Superseded Departments, Physics.
    Appelbe, D. E.
    Barton, C. J.
    Simpson, J.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Hadinia, Baharak
    KTH, Superseded Departments, Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Eeckhaudt, S.
    Grahn, T.
    Greenlees, P. T.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Kettunen, H.
    Leino, M.
    Leppanen, A. P.
    Nieminen, P.
    Pakarinen, J.
    Rahkila, P.
    Scholey, C.
    Uusitalo, J.
    Page, R. D.
    Paul, E. S.
    Wiseman, D. R.
    Recoil decay tagging of gamma rays in the extremely neutron-deficient nucleus Os-1622004In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 70, no 1Article in journal (Refereed)
    Abstract [en]

    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.

  • 109. Joss, D T
    et al.
    Paul, E S
    Clark, R M
    Lee, I Y
    Asztalos, S J
    Becker, J A
    Bernstein, L
    Cederwall, Bo
    Deleplanque, M A
    Diamond, R M
    Fallon, P
    Farris, L P
    Hauschild, K
    Hibbert, I M
    Kelly, W H
    Macchiavelli, A O
    Nolan, P J
    O'Brien, N J
    Semple, A T
    Stephens, F S
    Wadsworth, R
    Lifetime measurements of a triaxial band in Ce-1331998In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 58, no 6, p. 3219-3222Article in journal (Refereed)
    Abstract [en]

    Lifetimes of states within a triaxial band belonging to;the gamma-soft nucleus Ce-133 have been determined through a Doppler-broadened line shape analysis. A value, Q(t)approximate to 2.2 eb, has been found for the transition quadrupole moment which is considerably smaller than that of superdeformed structures (Q(t)approximate to 7.4 e b) in this mass region. The results are discussed in terms of deformation self-consistent calculations based on the total Routhian surface formalism. [S0556-2813(98)01912-8].

  • 110. Joss, D. T.
    et al.
    Simpson, J.
    Appelbe, D. E.
    Barton, C. J.
    Warner, D. D.
    Lagergren, K.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hadinia, B.
    Eeckhaudt, S.
    Grahn, T.
    Greenlees, P. T.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Kettunen, H.
    Leino, M.
    Leppanen, A. P.
    Nieminen, P.
    Pakarinen, J.
    Perkowski, J.
    Rahkila, P.
    Scholey, C.
    Uusitalo, J.
    de Vel, K. Van
    Page, R. D.
    Paul, E. S.
    Wiseman, D. R.
    Riley, M. A.
    Yrast states and band crossings in the neutron-deficient platinum isotopes Pt169-1732006In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 74, no 1Article in journal (Refereed)
    Abstract [en]

    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.

  • 111. Joss, D. T.
    et al.
    Simpson, J.
    Page, R. D.
    King, S. L.
    Amzal, N.
    Appelbe, D. E.
    Bäck, Torbjörn
    KTH, Superseded Departments, Physics.
    Bentley, M. A.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Cocks, J. F. C.
    Cullen, D. M.
    Greenlees, P. T.
    Helariutta, K.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Kankaanpää, H.
    Keenan, A.
    Kettunen, H.
    Kuusiniemi, P.
    Leino, M.
    Muikku, M.
    Savelius, A.
    Uusitalo, J.
    Warner, D. D.
    Williams, S. J.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Yrast spectroscopy in the neutron-deficient nucleus Os-1692002In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 66, no 5Article in journal (Refereed)
    Abstract [en]

    Excited states in the neutron-deficient isotope Os-169 have been identified for the first time in an experiment using the Jurosphere gamma-ray spectrometer in conjunction with the Ritu gas-filled recoil separator. The problems associated with identifying neutron-deficient isotopes produced with low fusion cross sections against a high background of competing channels, including fission, have been overcome by using the recoil-decay tagging technique. The band structures observed in Os-169 are interpreted in the context of the systematics of neighboring nuclei and the predictions of cranked Woods-Saxon calculations. The systematics of the second (i(13/2))(2) neutron alignment in this region are discussed.

  • 112. Joss, D. T.
    et al.
    Simpson, J.
    Paul, E. S.
    Page, R. D.
    Amzal, N.
    Appelbe, D. E.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Cocks, J. F. C.
    Cullen, D. M.
    Greenlees, P. T.
    Helariutta, K.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Kankaanpää, H.
    Keenan, A.
    Kettunen, H.
    King, S. L.
    Kuusiniemi, P.
    Leino, M.
    Muikku, M.
    Savelius, A.
    Uusitalo, J.
    Strongly coupled bands in the neutron-deficient nucleus Re-1672003In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 68, no 1Article in journal (Refereed)
    Abstract [en]

    Excited states in the neutron-deficient nucleus Re-167 have been observed in a recoil-tagging experiment performed with the Jurosphere gamma-ray spectrometer in conjunction with the RITU gas-filled recoil separator. The low-spin yrast band, based on a proton h(11/2) orbital, comprises a strongly coupled band and exhibits significant signature splitting, indicative of a triaxial shape with gamma<0degrees. At higher spin the rotational alignment of a pair of i(13/2) neutrons induces a transition to an axial prolate shape resulting in a drastic reduction of the signature splitting. Two other strongly coupled bands have been established and their structures are discussed in terms of quasiparticle configurations.

  • 113.
    Karlgren, Daniel
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Clark, R. M.
    Ragnarsson, I.
    Svensson, C. E.
    Ward, D.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Andreoiu, C.
    Austin, R. A. E.
    Carpenter, M. P.
    Cromaz, M.
    Deleplanque, M. A.
    Diamond, R. M.
    Fallon, P.
    Gorgen, A.
    Janssens, R. V. F.
    Khoo, T. L.
    Kondev, F.
    Lane, G. J.
    Lauritsen, T.
    Lee, I. Y.
    Macchiavelli, A. O.
    Rodinger, T.
    Rudolph, D.
    Sarantites, D. G.
    Seweryniak, D.
    Steinhardt, T.
    Stephens, F. S.
    Thelen, O.
    Vetter, K.
    Waddington, J. C.
    High-angular-momentum structures in Zn-642004In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 69, no 3, p. 034330-Article in journal (Refereed)
    Abstract [en]

    High-angular-momentum states in Zn-64 were populated in the Ca-40(Si-28,4p) reaction at a beam energy of 122 MeV. Evaporated, light, charged particles were identified by the Microball, while gamma rays were detected using the Gammasphere array. The main focus of this paper is on two strongly coupled, collective bands. The yrast band, which was previously known, has been linked to lower-lying states establishing the excitation energies and angular momenta of in-band states for the first time. The newly identified excited band decays to the yrast band but firm angular-momentum assignments could not be made. In order to interpret these structures cranked-Nilsson-Strutinsky calculations have been performed. The calculations have been extended to account for the distribution of nucleons within a configuration. The yrast collective band is interpreted as based on the pi(f(7/2))(-1)(p(3/2)f(5/2))(2)(g(9/2))(1)nu(p(3/2)f(5/2))(4)(g(9/2))(2) configuration. There are several possible interpretations of the second band but it is difficult to distinguish between the different possibilities.

  • 114.
    Karlgren, Daniel
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Huyse, M.
    Van de Vel, K.
    Van Duppen, P. B
    Alpha-decay hindrance factors: A probe of mean-field wave function2006In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 73, no 6, p. 064304-Article in journal (Refereed)
    Abstract [en]

    A simple model to calculate alpha-decay hindrance factors (HF) with special emphasis on the shape coexistence in the Pb-Po region is presented. Using deformation values obtained from potential energy surface (PES) calculations as the only input, hindrance factors for the alpha decay of Rn and Po isotopes are calculated. The fair agreement between experimental and theoretical hindrance factors suggest that the wave function obtained from the energy minima of the PES calculations contains an important part of the correlations that play a role for the alpha decay. The model is applicable to shape coexistence in the Po and Pb region when minima are well defined. The calculated HF that emerge from these calculations render a different interpretation than the commonly assumed n-particle n-hole picture of the intruder states in the Pb region.

  • 115. Kelsall, N. S.
    et al.
    Fischer, S. M.
    Balamuth, D. P.
    Ball, G. C.
    Carpenter, M. P.
    Clark, R. M.
    Durell, J.
    Fallon, P.
    Freeman, S. J.
    Hausladen, P. A.
    Janssens, R. V. F.
    Jenkins, D. G.
    Leddy, M. J.
    Lister, C. J.
    Macchiavelli, A. O.
    Sarantites, D. G.
    Schmidt, D. C.
    Seweryniak, D.
    Svensson, C. E.
    Varley, B. J.
    Vincent, S.
    Wadsworth, R.
    Wilson, A. N.
    Afanasjev, A. V.
    Frauendorf, S.
    Ragnarsson, I.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Testing mean-field models near the N=Z line: gamma-ray spectroscopy of the T-z=1/2 nucleus Kr-732002In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 65, no 4Article in journal (Refereed)
    Abstract [en]

    Excited states in the N=Z+1 nucleus Kr-73 have been investigated using the Ca-40(Ar-36,2pn) and Ca-40(Ca-40,alpha2pn) reactions at 145 and 160 MeV, respectively. gamma rays were detected using the Gammasphere array and events were recorded in coincidence with charged-particle and neutron detectors. The three previously observed bands were extended to high spin, and a new unfavored positive-parity band has been observed. The alignment characteristics and decay properties of the bands are all consistent with large-deformation prolate rotation, with no clear evidence for oblate bands or shape coexistence. This is quite different from neighboring Kr-72,Kr-74, indicating a strong shape-stabilizing role for the valence neutron. The experimental results are compared to extended total Routhian surface, cranked Nilsson Strutinsky, and cranked relativistic mean-field calculations. The results suggest that the paired calculations lack some important physics. Neutron-proton correlations may be the missing ingredient. There is also evidence for an unusual band crossing in the negative-parity bands, which may indicate the presence of T=0 pairing correlations. At high spin all the models can reproduce the experimental data.

  • 116. Khan, E
    et al.
    Sandulescu, Nicolae
    KTH, School of Engineering Sciences (SCI), Physics.
    Van Giai, N
    Grasso, M
    Two-neutron transfer in nuclei close to the drip line2004In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 69, no 1, p. 014314-Article in journal (Refereed)
    Abstract [en]

    We investigate the two-neutron transfer modes induced by (t,p) reactions in neutron-rich oxygen isotopes. The nuclear response to the pair transfer is calculated in the framework of continuum quasiparticle random phase approximation (cQRPA). The cQRPA allows a consistent determination of the residual interaction and an exact treatment of the continuum coupling. The (t,p) cross sections are calculated within the distorted wave Born approximation approach and the form factors are evaluated by different methods: macroscopically, following the Bayman and Kallio method, and fully microscopically. A significant part of the cross section corresponds to a high-lying collective mode built entirely upon continuum quasiparticle states.

  • 117. Kobyakov, D.
    et al.
    Pethick, Christopher
    KTH, Centres, Nordic Institute for Theoretical Physics NORDITA.
    Dynamics of the inner crust of neutron stars: Hydrodynamics, elasticity, and collective modes2013In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 87, no 5, p. 055803-Article in journal (Refereed)
    Abstract [en]

    We present calculations of the hydrodynamics of the inner crust of neutron stars, where a superfluid neutron liquid coexists with a lattice of neutron-rich nuclei. The long-wavelength collective oscillations are combinations of phonons in the lattice and phonons in the superfluid neutrons. Velocities of collective modes are calculated from information about effective nucleon-nucleon interactions derived from Lattimer and Swesty's microscopic calculations based on a compressible liquid drop picture of the atomic nuclei and the surrounding neutrons.

  • 118. Koester, U.
    et al.
    Stone, N. J.
    Flanagan, K. T.
    Stone, J. Rikovska
    Fedosseev, V. N.
    Kratz, K. L.
    Marsh, B. A.
    Materna, T.
    Mathieu, L.
    Molkanov, P. L.
    Seliverstov, M. D.
    Serot, O.
    Sjödin, Anna Marica
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Volkov, Yu. M.
    In-source laser spectroscopy of (75,77,78)Cu: Direct evidence for a change in the quasiparticle energy sequence in (75,77)Cu and an absence of longer-lived isomers in (78)Cu2011In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 84, no 3, p. 034320-Article in journal (Refereed)
    Abstract [en]

    This paper describes measurements on the isotopes (75,77,78)Cu by the technique of in-source laser spectroscopy, at the ISOLDE facility, CERN. The role of this technique is briefly discussed in the context of this and other, higher resolution, methods applied to copper isotopes in the range (57-78)Cu. The data, analyzed in comparison with previous results on the lighter isotopes (59,63)Cu, establish the ground-state nuclear spin of (75,77)Cu as 5/2 and yield their magnetic dipole moments as +1.01(5)mu(N) and +1.61(5)mu(N), respectively. The results on (78)Cu show no evidence for long-lived isomerism at this mass number and are consistent with a spin in the range 3-6 and moment of 0.0(4) mu(N).

  • 119. LaFosse, D R
    et al.
    Sarantites, D G
    Baktash, C
    Asztalos, S
    Brinkman, M J
    Cederwall, Bo
    Clark, R M
    Devlin, M
    Fallon, P
    Gross, C J
    Jin, H Q
    Lee, I Y
    Lerma, F
    Macchiavelli, A O
    MacLeod, R
    Rudolph, D
    Stracener, D W
    Yu, C H
    Search for hyperdeformation in Gd-146,Gd-1471996In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 54, no 4, p. 1585-1588Article in journal (Refereed)
    Abstract [en]

    A search was undertaken to look for evidence of hyperdeformation in Gd-146,Gd-147. Three experiments employing Gammasphere for gamma-ray detection coupled with the Microball for channel selection via charged particle detection were carried out with increasing detection sensitivity and statistics. No definitive evidence for band structures that could be assigned to hyperdeformation could be found. Candidates previously reported are shown not to have properties consistent with a band structure.

  • 120.
    Lagergren, Karin
    et al.
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Clark, R. M.
    Fallon, P.
    Gorgen, A.
    Issa, Tomas
    KTH, Superseded Departments, Physics.
    Janssens, R. V. F.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Macchiavelli, A. O.
    Milechina, L.
    KTH, Superseded Departments, Physics.
    Sarantites, D. G.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Shape evolution in the superdeformed A approximate to 80-90 mass region2003In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 68, no 6, p. 643091-643095Article in journal (Refereed)
    Abstract [en]

    Superdeformed bands in Mo-88, Tc-89, and Tc-91 were populated using a Ca-40 beam with an energy of 185 MeV, impinging on a backed Ni-58 target. gamma rays and charged particles emitted in the reactions were detected using the Gammasphere Ge detector array and the CsI(TI) array Microball. Average transition quadrupole moments Q(t) with significantly improved accuracy compared to earlier work, were deduced for the bands using the residual doppler shift technique. The experimental results were included into a systematic study of the Q(t) values throughout the superdeformed mass 80-90 region. The superdeformed shell gaps are predicted to move towards larger deformations with increasing Z and N in this mass region. This trend is confirmed by the experimental Q(t) values.

  • 121.
    Lagergren, Karin
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Joss, D. T.
    Paul, E. S.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Simpson, J.
    Appelbe, D. E.
    Barton, C. J.
    Eeckhaudt, S.
    Grahn, T.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jones, P.
    Julin, R.
    Juutinen, S.
    Kettunen, H.
    Leino, M.
    Leppanen, A. -P
    Nieminen, P.
    Page, R. D.
    Pakarinen, J.
    Perkowski, J.
    Rahkila, P.
    Scholey, C.
    Uusitalo, J.
    Warner, D. D.
    Wiscman, D. R.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    gamma-soft shapes and quasiparticle excitations in Ta-161(73)882011In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 83, no 1, p. 014313-Article in journal (Refereed)
    Abstract [en]

    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.

  • 122.
    Lagergren, Karin
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Joss, D. T.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Barton, C. J.
    Eeckhaudt, S.
    Grahn, T.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Karlgren, Daniel
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Kettunen, H.
    Leino, M.
    Leppanen, A. P.
    Nieminen, P.
    Nyman, M.
    Page, R. D.
    Pakarinen, J.
    Paul, E. S.
    Rahkila, P.
    Scholey, C.
    Simpson, J.
    Uusitalo, J.
    Wiseman, D. R.
    High-spin states in the proton-unbound nucleus Re-1612006In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 74, no 2, p. 024316-Article in journal (Refereed)
    Abstract [en]

    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.

  • 123. 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, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    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, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    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 Ag122-1262013In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 87, no 3, p. 034308-Article in journal (Refereed)
    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.

  • 124. Lee, I Y
    et al.
    Asztalos, S
    Deleplanque, M A
    Cederwall, Bo
    Diamond, R M
    Fallon, P
    Macchiavelli, A O
    Phair, L
    Stephens, F S
    Wozniak, G J
    Frauendorf, S G
    Becker, J A
    Hendry, E A
    Hua, P F
    Sarantites, D G
    Saladin, J X
    Yu, C H
    Study of neutron-rich nuclei using deep-inelastic reactions1997In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 56, no 2, p. 753-759Article in journal (Refereed)
    Abstract [en]

    We have used the Ca-48+Yb-176 reaction to study the population of high-spin states in neutron-rich nuclei by deep-inelastic reactions. Using Gammasphere, we observed gamma transitions from nuclei several neutrons richer than the target. Yrast states with spin up to 20 were populated in this reaction. High-spin states in Yb-175,Yb-177,Yb-178 were observed. In this region of reduced pairing, a reference based on experimental data was used to derive experimental Routhians. Systematics of experimental Routhians in neutron-rich Yb nuclei compare well with cranked shell-model calculations.

  • 125. Lerma, F.
    et al.
    Reviol, W.
    Chiara, C. J.
    Devlin, M.
    LaFosse, D. R.
    Sarantites, D. G.
    Baktash, C.
    Jin, H. Q.
    Clark, R. M.
    Lee, I. Y.
    Macchiavelli, A. O.
    Satula, W.
    Soltysik, D.
    Tabor, S. L.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Superdeformed bands in Sr80-83, Y82-84, Zr-83,Zr-84: Transition quadrupole moments, moments of inertia, and configuration assignments2003In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 67, no 4, p. 044310-Article in journal (Refereed)
    Abstract [en]

    Multiple superdeformed bands in the nuclei Sr80-83, Y82-84, and Zr-83,Zr-84 have been studied in a backed-target experiment, using the Gammasphere and the Microball 4pi detector arrays. For 15 bands in these nuclei, average transition quadrupole moments have been measured with high accuracy, using the Doppler-shift attenuation method. Among these are the newly observed superdeformed bands in Y-83,Y-84, which are isospectral with the bands in Sr-82,Sr-83. These isospectral bands have nearly identical transition quadrupole moments. Two of the bands in Sr-81 interact and cross transitions between them are observed. The present measurements place stringent conditions on configuration assignments for the bands obtained from two types of mean-field calculations, leading to a consistent understanding of the mass similar to80 superdeformed bands. The assignments for different bands arise from one or more nucleons occupying the N-0=5h(11/2) intruder orbital.

  • 126.
    Li, Hongjie
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. Tsinghua University, People's Republic of China.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Doncel, Maria
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jakobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. University of Jyvaskyla, Finland.
    Auranen, K.
    Boenig, S.
    Drummond, M. C.
    Grahn, T.
    Greenlees, P.
    Herzan, A.
    Julin, R.
    Juutinen, S.
    Konki, J.
    Kroell, T.
    Leino, M.
    McPeake, C.
    O'Donnell, D.
    Page, R. D.
    Pakarinen, J.
    Partanen, J.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Saren, J.
    Saygi, B.
    Scholey, C.
    Sorri, J.
    Stolze, S.
    Taylor, M. J.
    Thornthwaite, A.
    Uusitalo, J.
    Xiao, Z. G.
    Recoil-decay tagging spectroscopy of W-162(74)882015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 1, article id 014326Article in journal (Refereed)
    Abstract [en]

    Excited states in the highly neutron-deficient nucleus W-162 have been investigated via the Mo-92(Kr-78, 2 alpha) W-162 reaction. Prompt gamma rays were detected by the JUROGAM II high-purity germanium detector array and the recoiling fusion-evaporation products were separated by the recoil ion transport unit (RITU) gas-filled recoil separator and identified with the gamma recoil electron alpha tagging (GREAT) spectrometer at the focal plane of RITU. gamma rays from W-162 were identified uniquely using mother-daughter and mother-daughter-granddaughter alpha-decay correlations. The observation of a rotational-like ground-state band is interpreted within the framework of total Routhian surface (TRS) calculations, which suggest an axially symmetric ground-state shape with a gamma-soft minimum at beta(2) approximate to 0.15. Quasiparticle alignment effects are discussed based on cranked shell model calculations. New measurements of the W-162 ground-state alpha-decay energy and half-life were also performed. The observed alpha-decay energy agrees with previous measurements. The half-life of W-162 was determined to be t(1/2) = 990(30) ms. This value deviates significantly from the currently adopted value of t(1/2) = 1360(70) ms. In addition, the alpha-decay energy and half-life of Os-166 were measured and found to agree with the adopted values.

  • 127.
    Li, Hongjie
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. Tsinghua Univ, Dept Phys, Beijing 100084, Peoples R China.
    Doncel, Maria
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Patial, Maria
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jakobsson, U.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland.
    Auranen, K.
    Boenig, S.
    Drummond, M.
    Grahn, T.
    Greenlees, P.
    Herzan, A.
    Joss, D. T.
    Julin, R.
    Juutinen, S.
    Konki, J.
    Kroell, T.
    Leino, M.
    McPeake, C.
    O'Donnell, D.
    Page, R. D.
    Pakarinen, J.
    Partanen, J.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Saren, J.
    Saygi, B.
    Scholey, C.
    Sorri, J.
    Stolze, S.
    Taylor, M. J.
    Thornthwaite, A.
    Uusitalo, J.
    Xiao, Z. G.
    First identification of rotational band structures in Re-166(75)912015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 1, article id 014310Article in journal (Refereed)
    Abstract [en]

    Excited states in the odd-odd, highly neutron-deficient nucleus Re-166 have been investigated via the Mo-92(Kr-78, 3p1n)Re-166 reaction. Prompt gamma rays were detected by the JUROGAM II. gamma-ray spectrometer, and the recoiling fusion-evaporation products were separated by the recoil ion transport unit (RITU) gas-filled recoil separator and implanted into the Gamma Recoil Electron Alpha Tagging spectrometer located at the RITU focal plane. The tagging and coincidence techniques were applied to identify the gamma-ray transitions in Re-166, revealing two collective, strongly coupled rotational structures, for the first time. The more strongly populated band structure is assigned to the pi h(11/2)[514]9/2(-) circle times vi(13/2)[660]1/2(+) Nilsson configuration, while the weaker structure is assigned to be built on a two-quasiparticle state of mixed pi h(11/2)[514]9/2(-) circle times v[h(9/2)f(7/2)]3/2(-) character. The configuration assignments are based on the electromagnetic characteristics and rotational properties, in comparison with predictions from total Routhian surface and particle-rotor model calculations.

  • 128.
    Li, Hongjie
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    et al,
    Recoil-decay tagging spectroscopy of 16274W88In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490XArticle in journal (Refereed)
  • 129.
    Li, Hongjie J.
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Xiao, Z. G.
    Zhu, S. J.
    Patial, Monika
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Zhang, Z.
    Wang, R. S.
    Yi, H.
    Yan, W. H.
    Cheng, W. J.
    Huang, Y.
    Lyu, L. M.
    Zhang, Y.
    Wu, X. G.
    He, C. Y.
    Zheng, Y.
    Li, G. S.
    Li, C. B.
    Li, H. W.
    Liu, J. J.
    Luo, P. W.
    Hu, S. P.
    Wang, J. L.
    Wu, Y. H.
    Collective band structures in the Tc-99 nucleus2015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 91, no 5, article id 054314Article in journal (Refereed)
    Abstract [en]

    Excited states in Tc-99 with energies up to 6 MeV have been populated using the Zr-96(Li-7, 4n)Tc-99 reaction with a laboratory beam energy of 35 MeV. Coincident gamma rays from excited nuclei produced in the reactions were detected using an array of coaxial, planar, and clover-type high-purity germanium detectors. A total of 60 new gamma-ray transitions and 21 new levels are identified and placed into a new level scheme. Two collective bands assigned to be built on the pi g(9/2)[422]5/2(+) and pi p(1/2)[301]1/2(-) Nilsson configurations have been extended with spins up to 35/2 and 33/2 h, respectively. Backbending and signature inversion have been observed in the yrast band. The large signature splitting of the positive-parity band in Tc-99 may be caused by a triaxial deformation, which agrees well with the electromagnetic properties, theoretical calculations based on total Routhian surface, and triaxial particle-rotor model calculations.

  • 130. Litzinger, J.
    et al.
    Blazhev, A.
    Dewald, A.
    Didierjean, F.
    Duchene, G.
    Fransen, C.
    Lozeva, R.
    Sieja, K.
    Verney, D.
    de Angelis, G.
    Bazzacco, D.
    Birkenbach, B.
    Bottoni, S.
    Bracco, A.
    Braunroth, T.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Corradi, L.
    Crespi, F. C. L.
    Desesquelles, P.
    Eberth, J.
    Ellinger, E.
    Farnea, E.
    Fioretto, E.
    Gernhaeuser, R.
    Goasduff, A.
    Goergen, A.
    Gottardo, A.
    Grebosz, J.
    Hackstein, M.
    Hess, H.
    Ibrahim, F.
    Jolie, J.
    Jungclaus, A.
    Kolos, K.
    Korten, W.
    Leoni, S.
    Lunardi, S.
    Maj, A.
    Menegazzo, R.
    Mengoni, D.
    Michelagnoli, C.
    Mijatovic, T.
    Million, B.
    Moeller, O.
    Modamio, V.
    Montagnoli, G.
    Montanari, D.
    Morales, A. I.
    Napoli, D. R.
    Niikura, M.
    Pollarolo, G.
    Pullia, A.
    Quintana, B.
    Recchia, F.
    Reiter, P.
    Rosso, D.
    Sahin, E.
    Salsac, M. D.
    Scarlassara, F.
    Soederstroem, P. -A
    Stefanini, A. M.
    Stezowski, O.
    Szilner, S.
    Theisen, Ch.
    Dobon, J. J. Valiente
    Vandone, V.
    Vogt, A.
    Transition probabilities in neutron-rich Se-84,Se-862015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 6, article id 064322Article in journal (Refereed)
    Abstract [en]

    Reduced quadrupole transition probabilities for low-lying transitions in neutron-rich Se-84,Se-86 are investigated with a recoil distance Doppler shift (RDDS) experiment. The experiment was performed at the Istituto Nazionale di Fisica Nucleare (INFN) Laboratori Nazionali di Legnaro using the Cologne Plunger device for the RDDS technique and the AGATA Demonstrator array for the gamma-ray detection coupled to the PRISMA magnetic spectrometer for an event-by-event particle identification. In Se-86 the level lifetime of the yrast 2(1)(+) state and an upper limit for the lifetime of the 4(1)(+) state are determined for the first time. The results of Se-86 are in agreement with previously reported predictions of large-scale shell-model calculations using Ni78-I and Ni78-II effective interactions. In addition, intrinsic shape parameters of lowest yrast states in Se-86 are calculated. In semimagic Se-84 level lifetimes of the yrast 4(1)(+) and 6(1)(+) states are determined for the first time. Large-scale shell-model calculations using effective interactions Ni78-II, JUN45, jj4b, and jj4pna are performed. The calculations describe B(E2; 2(1)(+) -> 0(1)(+)) and B(E2; 6(1)(+) -> 4(1)(+)) fairly well and point out problems in reproducing the experimental B(E2; 4(1)(+) -> 2(1)(+)).

  • 131. Liu, H. L.
    et al.
    Xu, F. R.
    Xu, S. W.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Walker, P. M.
    High-spin isomeric structures in exotic odd-odd nuclei: Exploration of the proton drip line and beyond2007In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 76, no 3, p. 034313-Article in journal (Refereed)
    Abstract [en]

    We investigate the role of two-quasiparticle isomeric states along the proton drip line, using configuration-constrained potential-energy-surface calculations. In contrast to even-even nuclei, odd-odd nuclei can have coexisting low-lying two-quasiparticle states. The low excitation energy and high angular momentum can lead to long-lived isomers. Also, because of the hindrance by spin selection, the probabilities of beta and proton decays from high-spin isomers can be reduced significantly. The present calculations reproduce reasonably well the available data for observed isomers in such nuclei. Unobserved high-spin isomers are predicted, which could be useful for future experimental studies of exotic nuclei at and beyond the proton drip line.

  • 132. MACCHIAVELLI, AO
    et al.
    CEDERWALL, BO
    CLARK, RM
    DELEPLANQUE, MA
    DIAMOND, RM
    FALLEN, P
    LEE, IY
    STEPHENS, FS
    ASZTALOS, S
    C-4 SYMMETRY EFFECTS IN NUCLEAR ROTATIONAL MOTION1995In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 51, no 1, p. R1-R4Article in journal (Refereed)
  • 133. Mason, P.
    et al.
    Benzoni, G.
    Bracco, A.
    Camera, F.
    Million, B.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Lagergen, K.
    et al,
    Evidence for octupole correlations in Ba-124,Ba-1252005In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 72, no 6Article in journal (Refereed)
    Abstract [en]

    The gamma decay of the nuclei Ba-124,Ba-125 has been investigated by means of the EUROBALL spectrometer, coupled to the DIAMANT array of charged-particle detectors, using the reaction Ni-64 + Ni-64 at E-beam=255 and 261 MeV. In the nucleus Ba-125 six new E1 transitions have been found to link opposite-parity bands currently interpreted as nu d(5/2)(+g(7/2)),nu h(11/2) structures. The previously unknown J(pi) = 3(-) level in the nucleus Ba-124 has also been identified; its excitation energy is accurately reproduced by a microscopic calculation including octupole correlations. Both issues are bolstered by sizable B(E1)/B(E2) ratios.

  • 134. McNabb, D P
    et al.
    Baldsiefen, G
    Bernstein, L A
    Cizewski, J A
    Jin, H Q
    Younes, W
    Becker, J A
    Farris, L P
    Henry, E A
    Hughes, J R
    Lee, C S
    Asztalos, S J
    CEDERWALL, BO
    Clark, R M
    Deleplanque, M A
    Diamond, R M
    Fallon, P
    Lee, I Y
    Macchiavelli, A O
    Stephens, F S
    Superdeformation in Po-1981996In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 53, no 2, p. R541-R543Article in journal (Refereed)
    Abstract [en]

    The Yb-174(Si-29,5n) reaction at 148 MeV with thin targets was used to populate high-angular momentum states in Po-198. Resulting gamma rays were observed with Gammasphere. A weakly populated superdeformed band of 10 gamma-ray transitions was found and has been assigned to Po-198. This is the first observation of an SD band in the A approximate to 190 region in a nucleus with Z > 83. The J((2))) of the new band is very similar to those of the yrast SD bands in Hg-194 and Pb-196. The intensity profile suggests that this band is populated through states close to where the SD band crosses the yrast line and the angular momentum at which the fission process dominates.

  • 135. Naguleswaran, S.
    et al.
    Chakrawarthy, R. S.
    Garg, U.
    Lamkin, K. L.
    Smith, G.
    Walpe, J. C.
    Galindo-Uribarri, A.
    Janzen, V. P.
    Radford, D. C.
    Kaczarowski, R.
    Fossan, D. B.
    Lafosse, D. R.
    Vaska, P.
    Droste, C.
    Morek, T.
    Pilotte, S.
    DeGraaf, J.
    Drake, T.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Magnetic and intruder rotational bands in In-1132005In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 72, no 4, p. 044304-Article in journal (Refereed)
    Abstract [en]

    Excited states in In-113 were populated via the reactions Mo-100(O-18,p4n)In-113 and Pd-110(Li-7,4n)In-113. The two known Delta J=2 intruder bands, based on the pi g(7/2)circle times d(5/2) and pi h(11/2) orbitals, have been extended by 8h to spins (49/2(+))h and (55/2(-))h, respectively. The previous finding of three sequences of Delta J=1 gamma-ray transitions has been confirmed. A self-consistent cranked shell-model calculation gives a good description of the contrasting alignment patterns of the two Delta J=2 intruder bands. The intruder bands, the known sequences of M1 transitions, and spherical levels together represent a coexistence of three different excitation modes in this nucleus.

  • 136. 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, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Beck, T.
    Bednarczyk, P.
    Benlliure, J.
    Benzoni, G.
    Bruce, A. M.
    Casarejos, E.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Crespi, F. C. L.
    Detistov, P.
    Dombradi, Zs.
    Doornenbal, P.
    Geissel, H.
    Gerl, J.
    Grebosz, J.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hellstrom, M.
    Hoischen, R.
    Ilie, G.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    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)Cd2010In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 82, no 3, p. 034323-Article in journal (Refereed)
    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.

  • 137. Nieminen, P.
    et al.
    Juutinen, S.
    Andreyev, A. N.
    Cocks, J. F. C.
    Dorvaux, O.
    Eskola, K.
    Greenlees, P. T.
    Hauschild, K.
    Helariutta, K.
    Huyse, M.
    Jones, P. M.
    Julin, R.
    Kankaanpaa, H.
    Kettunen, H.
    Kuusiniemi, P.
    Le Coz, Y.
    Leino, M.
    Lonnroth, T.
    Muikku, M.
    Rahkila, P.
    Savelius, A.
    Uusitalo, J.
    Amzal, N.
    Hammond, N. J.
    Scholey, C.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    gamma-ray spectroscopy of Bi-191,Bi-1932004In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 69, no 6, p. 064326-Article in journal (Refereed)
    Abstract [en]

    Prompt and delayed gamma rays from Bi-191,Bi-193 have been identified using the recoil-decay tagging, isomer tagging, and recoil gating techniques, resulting in extensive level schemes for both nuclei. Excitation energies of the isomeric 13/2(+) states have been established and oblate strongly coupled bands built on them have been observed. The nearly spherical 9/2(-) ground-state bands appear to be crossed by more oblate-deformed low-lying structures. The properties of the bands feeding the 1/2(+) intruder states indicate some structural change between Bi-193 and Bi-191. The deformation associated with each of these states has been extracted from total Routhian surface calculations which also reveal the development of prolate minima with decreasing neutron number. B(M1)/B(E2) ratios have been measured for the observed strongly coupled bands in order to resolve the intrinsic excitations. The observed quasiparticle structures in Bi-193 and high-spin isomers both in Bi-193 and Bi-191 are interpreted based on the coupling of the odd proton to the even-even Pb core.

  • 138. O'Donnell, D.
    et al.
    Grahn, T.
    Joss, D. T.
    Simpson, J.
    Scholey, C.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Bianco, L.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ganioglu, Ela
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Spectroscopy of the neutron-deficient nucleus Os-167(91)2009In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 79, no 6Article in journal (Refereed)
    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.

    .

     

  • 139. O'Donnell, D.
    et al.
    Simpson, J.
    Scholey, C.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Greenlees, P. T.
    Jakobsson, U.
    Jones, P.
    Joss, D. T.
    Judson, D. S.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Labiche, M.
    Leino, M.
    Nyman, M.
    Page, R. D.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Sapple, P. J.
    Saren, J.
    Thomson, J.
    Uusitalo, J.
    Watkins, H. V.
    First observation of excited states in Hg-175(95)2009In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 79, no 5, p. 051304-Article in journal (Refereed)
    Abstract [en]

    Excited states of the neutron-deficient nucleus Hg-175, populated using fusion-evaporation reactions, are reported for the first time. The spin and parity of the ground state has been determined to be I-pi=7/2(-) through measurements of the alpha decay to the daughter nucleus Pt-171. A structure based on an isomeric state [T-1/2=0.34(3) mu s] with I-pi=13/2(+) and its decay path to the ground state have been established. The observed structures are interpreted in terms of single-particle configurations, and the trends of coexisting shapes in neighboring nuclei are discussed.

  • 140. OLIVEIRA, JRB
    et al.
    FRAUENDORF, S
    DELEPLANQUE, MA
    CEDERWALL, BO
    DIAMOND, RM
    MACCHIAVELLI, AO
    STEPHENS, FS
    BURDE, J
    DRAPER, JE
    DUYAR, C
    RUBEL, E
    BECKER, JA
    HENRY, EA
    BRINKMAN, MJ
    KUHNERT, A
    STOYER, MA
    WANG, TF
    HIGH-K BANDS IN THE YB-166 REGION1994In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 50, no 3, p. 1360-1369Article in journal (Refereed)
    Abstract [en]

    High-K bands have been observed in the Yb-166,Yb-167,Yb-168 isotopes following the Sn-124(Ca-48,xn gamma) reaction. The nu h(11/2) bend in Yb-167 has been extended to higher spins. The high-K bands in the even-even isotopes were observed for the first time and show very high B(M1)/B(E2) ratios. Configuration assignments for the new bands are proposed. The results are interpreted within the tilted cranking model.

  • 141. Page, R. D.
    et al.
    Bianco, L.
    Darby, I. G.
    Uusitalo, J.
    Joss, D. T.
    Grahn, T.
    Herzberg, R. -D
    Pakarinen, J.
    Thomson, J.
    Eeckhaudt, S.
    Greenlees, P. T.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Leino, M.
    Leppanen, A. -P
    Nyman, M.
    Rahkila, P.
    Saren, J.
    Scholey, C.
    Steer, A.
    Hornillos, M. B. Gomez
    Al-Khalili, J. S.
    Cannon, A. J.
    Stevenson, P. D.
    Erturk, S.
    Gall, B.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Venhart, M.
    Simpson, J.
    alpha decay of Re-159 and proton emission from Ta-1552007In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 75, no 6, p. 061302-Article in journal (Refereed)
    Abstract [en]

    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.

  • 142. Pauwels, D.
    et al.
    Radulov, D.
    Walters, W. B.
    Darby, I. G.
    De Witte, H.
    Diriken, J.
    Fedorov, D. V.
    Fedosseev, V. N.
    Fraile, L. M.
    Huyse, M.
    Koester, U.
    Marsh, B. A.
    Popescu, L.
    Seliverstov, M. D.
    Sjödin, A. Marica
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Van den Bergh, P.
    Van de Walle, J.
    Van Duppen, P.
    Venhart, M.
    Wimmer, K.
    Gamow-Teller decay population of Ni-64 levels in the decay of 1(+) Co-642012In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 86, no 6, p. 064318-Article in journal (Refereed)
    Abstract [en]

    The Co-64 beta-decay feeding levels in the well-studied Ni-64 nucleus were investigated. Whereas the previously known Co-64 decay scheme merely contained 2 gamma rays, the decay scheme established in this work contains 18, of which 5 are observed in this work and 6 were previously observed in an (n, gamma) study but not placed in the Ni-64 level scheme. Surprisingly, one additional level-placed at an excitation energy of 3578.7 keV-could be determined. The observed beta-decay paths involve allowed nu f(5/2) -> pi f(7/2) and nu p(1/2) -> pi p(3/2) transitions. Three strongly fed levels around 4 MeV are interpreted to possess possible proton-intruder character.

  • 143. Perries, S
    et al.
    Astier, A
    Ducroux, L
    Meyer, M
    Redon, N
    Petrache, C M
    Bazzacco, D
    Falconi, G
    Lunardi, S
    Lunardon, M
    Alvarez, C R
    Ur, C A
    Venturelli, R
    Viesti, G
    Deloncle, I
    Porquet, M G
    de Angelis, G
    de Poli, M
    Fahlander, C
    Farnea, E
    Foltescu, D
    Gadea, A
    Napoli, D R
    Podolyak, Z
    Bracco, A
    Frattini, S
    Leoni, S
    CEDERWALL, BO
    Johnson, A
    Wyss, Ramon A
    Decay-out of the yrast superdeformed band in Nd-136: Towards an experimental extraction of the neutron pairing gap at large deformation1999In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 60, no 6, article id 064313Article in journal (Refereed)
    Abstract [en]

    A study of the Nd-136 nucleus has been performed with the EUROBALL III multidetector to establish the decay-out of the yrast superdeformed (SD) band. Three discrete linking transitions (754, 1456, and 1493 keV) have been discovered, establishing the position of the SD band at 7.03 MeV excitation energy with proposed spin and parity 17((-)) for the lowest observed SD state. Neutron pairing gap parameters for SD shapes have been extracted in Nd isotopes, using the strong-coupling model and odd-even mass difference formulas. The major conclusion of our phenomenological analysis is that the pairing correlations do subsist in the SD configurations of nuclei in the A = 130 mass region. [S0556-2813(99)01312-6].

  • 144. Petrache, C. M.
    et al.
    Ragnarsson, I.
    Naidja, H.
    Nowacki, F.
    Leguillon, R.
    Zerrould, T.
    Greenlees, P. T.
    Jacobsson, Ulla
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Jones, P.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Leino, M.
    Nyman, M.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Uusitalo, J.
    Search for the terminating 27(-) state in Nd-1402015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 3, article id 034314Article in journal (Refereed)
    Abstract [en]

    In the search for the fully aligned 27(-) state in Nd-140 predicted by cranked Nilsson-Strutinsky calculations, new close-to-spherical high-spin states have been discovered. Both the close-to-spherical and the triaxial calculated states are in good agreement with the experimental results, supporting the existence of shape coexistence up to very high spins. Shell-model calculations using a newly developed effective interaction for the 50 <= N, Z <= 82 mass region are in good agreement with the observed spherical states. The comparison between the experimental and calculated level energies allowed the relative energy to be established between several proton and neutron orbitals at high energy and spins.

  • 145. Petri, M.
    et al.
    Paul, E. S.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Darby, I. G.
    Dimmock, M. R.
    Eeckhaudt, S.
    Ganioglu, E.
    Grahn, T.
    Greenlees, P. T.
    Hadinia, B.
    Jones, P.
    Joss, D. T.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Khaplanov, A.
    Leino, M.
    Nelson, L.
    Nyman, M.
    Page, R. D.
    Rahkila, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Uusitalo, J.
    Wadsworth, R.
    Nuclear levels in proton-unbound I-109: Relative single-particle energies beyond the proton drip line2007In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 76, no 5Article in journal (Refereed)
    Abstract [en]

    A level scheme has been constructed for the proton-unbound, T-z=3/2 nuclide I-109(53)56 following a recoil-decay-tagging experiment using the Ni-58(Fe-54, p2n gamma) reaction at a beam energy of 195 MeV. The experiment was performed using the highly efficient JUROGAM gamma-ray spectrometer in conjunction with the RITU gas-filled recoil separator and the GREAT focal-plane spectrometer. Cranking calculations are used to interpret band structures built on pi g(7/2) and pi h(11/2) states in a weakly deformed, triaxial nucleus.

  • 146. Peura, P.
    et al.
    Scholey, C.
    Joss, D. T.
    Juutinen, S.
    Julin, R.
    Baeck, T.
    CEDERWALL, BO
    Greenlees, P. T.
    Jakobsson, U.
    Jones, P.
    Judson, D. S.
    Ketelhut, S.
    Labiche, M.
    Leino, M.
    Nyman, M.
    O'Donnell, D.
    Page, R. D.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Sapple, P. J.
    Saren, J.
    Simpson, J.
    Thomson, J.
    Uusitalo, J.
    Watkins, H. V.
    Quasiparticle alignments and alpha-decay fine structure of Pt-175 (vol 89, 024316, 2014)2014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 89, no 4, article id 049902Article in journal (Refereed)
  • 147. Peura, P.
    et al.
    Scholey, C.
    Joss, D. T.
    Juutinen, S.
    Julin, R.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Greenlees, P. T.
    Jakobsson, U.
    Jones, P.
    Judson, D. S.
    Ketelhut, S.
    Labiche, M.
    Leino, M.
    Nyman, M.
    O'Donnell, D.
    Page, R. D.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Sapple, P. J.
    Sarén, J.
    Simpson, J.
    Thomson, J.
    Uusitalo, J.
    Watkins, H. V.
    Quasiparticle alignments and alpha-decay fine structure of Pt-1752014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 89, no 2, p. 024316-Article in journal (Refereed)
    Abstract [en]

    Excited states and decay properties of Pt-175 have been investigated using the Mo-92(Sr-86, 2pn) fusion-evaporation reaction. The JUROGAM I gamma-ray spectrometer and the GREAT spectrometer were used in conjunction with the gas-filled recoil separator RITU for the measurement of the radiation at the target and focal plane positions, respectively. Two new band structures, assigned to be based on the I-pi = (7/2(-)) ground state in Pt-175, have been established and the known yrast band has been extended up to I-pi = (49/2(+)). Rotational properties of the excited states in Pt-175 have been investigated within the cranked shell-model formalism. The low-frequency changes in the alignments of the positive-and negative-parity bands are interpreted as a sign of proton-pair excitations in the rotating core. Furthermore, the alpha-decay measurements reveal a candidate for a fourth alpha-decay branch in Pt-175, feeding a non-yrast state in Os-171.

  • 148. 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, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Benlliure, J.
    Benzoni, G.
    Bruce, A. M.
    Casarejos, E.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Crespi, F. C. L.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hellström, M.
    Hoischen, R.
    Ilie, G.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    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-1282011In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 83, no 4, p. 044328-Article in journal (Refereed)
    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(-).

  • 149. Procter, M. G.
    et al.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    et al.,,
    Electromagnetic transition strengths in Te-109(52)2012In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 86, no 3, p. 034308-Article in journal (Refereed)
    Abstract [en]

    Lifetime measurements have been made in the neutron-deficient nucleus Te-109 using the coincident recoil distance Doppler-shift method. The experimental B(E2) values have been compared with state-of-the-art shell-model calculations using the monopole-corrected realistic charge-dependent Bonn nucleon-nucleon potential. Lifetimes in the vh(11/2) band are consistent with an interpretation based on the deformation driving properties of a single valence neutron outside of the even-even tellurium core and highlight the unexpected presence of collective behavior as the N = 50 shell closure is approached. Lifetime measurements for the low-lying positive-parity states also appear to correlate well with shell-model calculations. In addition, a comparison with the proton-unbound nucleus I-109 suggests that the presence of a single decoupled valence proton affects the total measured B(E2) strengths in a manner that is not currently well understood.

  • 150. Procter, M. G.
    et al.
    Cullen, D. M.
    Taylor, M. J.
    Pakarinen, J.
    Auranen, K.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Braunroth, T.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Dewald, A.
    Grahn, T.
    Greenlees, P. T.
    Jakobsson, U.
    Julin, R.
    Juutinen, S.
    Herzan, A.
    Konki, J.
    Leino, M.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Partanen, J.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandelius, M.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Stolze, S.
    Uusitalo, J.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Isomer-tagged differential-plunger measurements in Xe-113(54)2013In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 87, no 1, p. 014308-Article in journal (Refereed)
    Abstract [en]

    The 278-keV M2 gamma decay from the vh(11/2) isomeric state in Xe-113 has been observed for the first time using the recoil-isomer tagging technique. The half-life of the isomer has been measured to be 6.9(3) mu s. The derived B(M2) value is in agreement with the trend of systematic measurements of M2 transition strengths in neutron-deficient tellurium and tin isotopes. The lifetime of the first excited state in the vh(11/2) band has been measured using the recoil distance Doppler-shift method. The extracted B(E2) value has been compared to theoretical CD-Bonn calculations and recent lifetime measurements in Te-109. This comparison of B(E2) values has been used to shed light on the possible influence of collective degrees of freedom on M2 transition strengths in the most neutron-deficient xenon nuclei. The vh(11/2) band is deduced to have a degree of deformation comparable with the ground-state bands of the even-mass xenon isotopes. However, the value deduced in this work indicates a loss of collective behavior when compared with the lower-mass Te-109. This result suggests that, while changes in deformation may be partly responsible for the observed trend in B(M2) values for increasing Z, other effects may also be present.

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