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  • 101.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    In-beam Study of Extremely Neutron deficient Nuclei Using the Recoil-Decay Tagging Technique2008Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The low-lying structures of the extremely neutron-deficient nuclei 106Te, 107Te, 110Xe, 170Ir and 172Au have been investigated experimentally. Prompt gamma rays emitted in fusion-evaporation reactions were detected by the Jurogam HPGe array. The gamma rays were assigned to specific reaction channels using the recoil-decay tagging technique provided by the gas-filled separator RITU and the GREAT focal-plane spectrometer. The experimental set-up and the technique used to extract the information from the experimental data are described in detail.

    Results were interpreted in terms of the nuclear shell model and Total Routhian Surface calculations. In addition, decay studies on 170Ir, 172Au and 164Re led to the discovery of new alpha-decay branches in these nuclei.

  • 102.
    Hadinia, Baharak
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Blomqvist, Jan
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ganioglu, Ela
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Greenlees, P. T.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Darby, I. G.
    Eeckhaudt, S.
    Ideguchi, E.
    Jones, P. M.
    Joso, D. T.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Lagergren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Leppanen, A. -P
    Leino, M.
    Nyman, M.
    Pakarinen, J.
    Paul, E. S.
    Petri, M.
    Rahkila, P.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Saren, J.
    Scholey, C.
    Uusitalo, J.
    Wadsworth, R.
    First identification of gamma-rays in Te-106 using recoil decay tagging technique2006In: Frontiers in Nuclear Structure Astrophysics, and Reactions: FINUSTAR / [ed] Harissopulos, S; Demetriou, P; Julin, R, MELVILLE, NY: AMER INST PHYSICS , 2006, Vol. 831, p. 457-459Conference paper (Refereed)
    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.

  • 103.
    Hadinia, Baharak
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Blomqvist, Jan
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ganioğlu, Ela
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Greenlees, Paul
    Department of Physics, University of Jyväskylä.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Lagergren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    et al.,
    First identification of excited states in 106Te and evidence for isoscalar-enhanced vibrational collectivity2005In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 72, no 4, p. 041303-1-041303-5Article in journal (Refereed)
    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.

  • 104.
    Hadinia, Baharak
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Joss, Dave
    CCLRC, Daresbury Laboratory, Warrington.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Page, Robert
    Oliver Lodge Laboratory, Department of Physics, University of Liverpool.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Lagergren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ganioğlu, Ela
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    et al.,
    In-beam gamma-ray and alpha-decay spectroscopy of 170Ir2007In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 76, no 4, p. 044312-1-044312-8Article in journal (Refereed)
    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.

  • 105.
    Hadinia, Baharak
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Page, R. D.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Scholey, C.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ganioglu, E.
    Hornillos, M. B. G.
    Grahn, T.
    Greenlees, P. T.
    Ideguchi, E.
    Jakobsson, U.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jones, P. M.
    Julin, R.
    Juutinen, J.
    Ketelhut, S.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Leino, M.
    Niikura, M.
    Nyman, M.
    Ozgur, I.
    Paul, E. S.
    Peura, P.
    Rahkila, P.
    Saren, J.
    Sorri, J.
    Uusitalo, J.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Identification of gamma rays from Au-172 and alpha decays of Au-172, Ir-168, and Re-1642009In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 80, no 6, p. 064310-Article in journal (Refereed)
    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.

  • 106. Hadynska-Klek, K.
    et al.
    Napiorkowski, P. J.
    Zielinska, M.
    Srebrny, J.
    Maj, A.
    Azaiez, F.
    Dobon, J. J. Valiente
    Kicinska-Habior, M.
    Nowacki, F.
    Naidja, H.
    Bounthong, B.
    Rodriguez, T. R.
    de Angelis, G.
    Abraham, T.
    Kumar, G. Anil
    Bazzacco, D.
    Bellato, M.
    Bortolato, D.
    Bednarczyk, P.
    Benzoni, G.
    Berti, L.
    Birkenbach, B.
    Bruyneel, B.
    Brambilla, S.
    Camera, F.
    Chavas, J.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Charles, L.
    Ciemala, M.
    Cocconi, P.
    Coleman-Smith, P.
    Colombo, A.
    Corsi, A.
    Crespi, F. C. L.
    Cullen, D. M.
    Czermak, A.
    Desesquelles, P.
    Doherty, D. T.
    Dulny, B.
    Eberth, J.
    Farnea, E.
    Fornal, B.
    Franchoo, S.
    Gadea, A.
    Giaz, A.
    Gottardo, A.
    Grave, X.
    Grebosz, J.
    Gorgen, A.
    Gulmini, M.
    Habermann, T.
    Hess, H.
    Isocrate, R.
    Iwanicki, J.
    Jaworski, G.
    Judson, D. S.
    Jungclaus, A.
    Karkour, N.
    Kmiecik, M.
    Karpinski, D.
    Kisielinski, M.
    Kondratyev, N.
    Korichi, A.
    Komorowska, M.
    Kowalczyk, M.
    Korten, W.
    Krzysiek, M.
    Lehaut, G.
    Leoni, S.
    Ljungvall, J.
    Lopez-Martens, A.
    Lunardi, S.
    Maron, G.
    Mazurek, K.
    Menegazzo, R.
    Mengoni, D.
    Merchan, E.
    Eczynski, W. M.
    Michelagnoli, C.
    Mierzejewski, J.
    Million, B.
    Myalski, S.
    Napoli, D. R.
    Nicolini, R.
    Niikura, M.
    Obertelli, A.
    Ozmen, S. F.
    Palacz, M.
    Prochniak, L.
    Pullia, A.
    Quintana, B.
    Rampazzo, G.
    Recchia, F.
    Redon, N.
    Reiter, P.
    Rosso, D.
    Rusek, K.
    Sahin, E.
    Salsac, M. -D
    Soderstrom, P. -A
    Stefan, I.
    Stezowski, O.
    Styczen, J.
    Theisen, Ch.
    Toniolo, N.
    Ur, C. A.
    Vandone, V.
    Wadsworth, R.
    Wasilewska, B.
    Wiens, A.
    Wood, J. L.
    Wrzosek-Lipska, K.
    Zieblinski, M.
    Superdeformed and Triaxial States in Ca-422016In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 117, no 6, article id 062501Article in journal (Refereed)
    Abstract [en]

    Shape parameters of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in Ca-42 were determined from E2 matrix elements measured in the first low-energy Coulomb excitation experiment performed with AGATA. The picture of two coexisting structures is well reproduced by new state-of-the-art large-scale shell model and beyond-mean-field calculations. Experimental evidence for superdeformation of the band built on 0(2)(+) has been obtained and the role of triaxiality in the A similar to 40 mass region is discussed. Furthermore, the potential of Coulomb excitation as a tool to study superdeformation has been demonstrated for the first time.

  • 107.
    Haefner, G.
    et al.
    Univ Cologne, Inst Kernphys, Cologne, Germany. outachkov, P.; Ameil, F.; Gerl, J.; Gorska, M.; Grawe, H.; Kojouharov, I; Kurz, N.; Schaffner, H..
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Zhu, Y.
    Tokyo Univ Sci, Shinjuku City, Tokyo, Japan.
    et al.,
    PROPERTIES OF gamma-DECAYING ISOMERS IN THE Sn-100 REGION REVISITED2019In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 50, no 3, p. 431-437Article in journal (Refereed)
    Abstract [en]

    The study of nuclei in the region around the N = Z doubly-magic nucleus -100 has been of long standing interest for the nuclear structure and clear astrophysics. Recently, Park et al. have reported on properties gamma-decaying isomers and isomeric ratios in the vicinity of Sn-100. at experiment was performed at the Radioactive Ion Beam Factory (RIBF) the RIKEN Nishina Center in Japan as a part of the EURICA campaign. utron-deficient nuclei were produced in a fragmentation reaction of a -124 primary beam on a 9 Be target at an energy of 345 MeV/A. condary ions were separated and identified in the BigRIPS fragment parator and implanted in the silicon detector array WAS3ABi. The data esented here were obtained in another experiment performed at the RIBF ing the same reaction but slightly different separator settings. New sults of ratios of isomeric population and half-lives of mma-decaying isomers populated in the experiment are presented.

  • 108. Hartman, H.
    et al.
    Gurell, J.
    Lundin, P.
    Schef, P.
    Hibbert, A.
    Lundberg, H.
    Mannervik, S.
    Norlin, Lars - Olov
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Royen, P.
    The FERRUM project: experimental and theoretical transition rates of forbidden [Sc II] lines and radiative lifetimes of metastable ScII levels2008In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 480, no 2, p. 575-580Article in journal (Refereed)
    Abstract [en]

    Context. In many plasmas, long-lived metastable atomic levels are depopulated by collisions (quenched) before they decay radiatively. In low-density regions, however, the low collision rate may allow depopulation by electric dipole (E1) forbidden radiative transitions, so-called forbidden lines (mainly M1 and E2 transitions). If the atomic transition data are known, these lines are indicators of physical plasma conditions and used for abundance determination. Aims. Transition rates can be derived by combining relative intensities between the decay channels, so-called branching fractions (BFs), and the radiative lifetime of the common upper level. We use this approach for forbidden [Sc II] lines, along with new calculations. Methods. Neither BFs for forbidden lines, nor lifetimes of metastable levels, are easily measured in a laboratory. Therefore, astrophysical BFs measured in Space Telescope Imaging Spectrograph (STIS) spectra of the strontium filament of Eta Carinae are combined with lifetime measurements using a laser probing technique on a stored ion-beam (CRYRING facility, MSL, Stockholm). These quantities are used to derive the absolute transition rates (A-values). New theoretical transition rates and lifetimes are calulated using the CIV3 code. Results. We report experimental lifetimes of the Sc II levels 3d(2) a(3)P(0,1,2) with lifetimes 1.28, 1.42, and 1.24 s, respectively, and transition rates for lines from these levels down to 3d4s a(3)D in the region 8270-8390 angstrom. These are the most important forbidden [Sc II] transitions. New calculations for lines and metastable lifetimes are also presented, and are in good agreement with the experimental data.

  • 109. Hartman, H
    et al.
    Schef, P
    Lundin, P
    Ellmann, A
    Johansson, S
    Lundberg, H
    Mannervik, S
    Norlin, Lars-Olov
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Rostohar, D
    Royen, P
    The FERRUM project: experimentally determined metastable lifetimes and transition probabilities for forbidden [Ti II] lines observed in eta Carinae2005In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 361, no 1, p. 206-210Article in journal (Refereed)
    Abstract [en]

    In the spectrum of an emission-line region ejected from the massive star Eta Carinae, called the strontium filament (SrF), forbidden lines from many elements, in particular [Sr II] and [Ti II], are observed. These lines are strong in this specific region and valuable for plasma diagnostics. Forbidden lines are not easily produced in laboratory light sources and the atomic parameters for these lines can thus not be measured in a straightforward way. We use a combination of laboratory and astrophysical measurements to determine transition probabilities for the [Ti II] lines. Lifetimes for metastable levels in Ti II are measured using a laser probing technique on a stored ion beam at CRYRING, MSL, Stockholm. Branching fractions from some of these levels are derived from Hubble Space Telescope/STIS spectra of the SrF. The astrophysical branching fractions are combined with the experimental lifetimes to determine absolute transition probabilities. We report lifetimes for the Ti II levels b(4)P(3/2), b(2)P(1/2), c(2)D(3/2) and c(2)D(5/2), in the range 0.29-17 s, and transition probabilities for eight parity-forbidden lines from the levels c(2)D(3/2) and c(2)D(5/2), along with uncertainty estimates.

  • 110. Hempelmann, N.
    et al.
    Hejny, V.
    Pretz, J.
    Stephenson, E.
    Augustyniak, W.
    Bagdasarian, Z.
    Bai, M.
    Barion, L.
    Berz, M.
    Chekmenev, S.
    Ciullo, G.
    Dymov, S.
    Etzkorn, F. -J
    Eversmann, D.
    Gaisser, M.
    Gebel, R.
    Grigoryev, K.
    Grzonka, D.
    Guidoboni, G.
    Hanraths, T.
    Heberling, D.
    Hetzel, J.
    Hinder, F.
    Kacharava, A.
    Kamerdzhiev, V.
    Keshelashvili, I.
    Koop, I.
    Kulikov, A.
    Lehrach, A.
    Lenisa, P.
    Lomidze, N.
    Lorentz, B.
    Maanen, P.
    Macharashvili, G.
    Magiera, A.
    Mchedlishvili, D.
    Mey, S.
    Mueller, F.
    Nass, A.
    Nikolaev, N. N.
    Pesce, A.
    Prasuhn, D.
    Rathmann, F.
    Rosenthal, M.
    Saleev, A.
    Schmidt, V.
    Semertzidis, Y.
    Shmakova, V.
    Silenko, A.
    Slim, J.
    Soltner, H.
    Stahl, A.
    Stassen, R.
    Stockhorst, H.
    Stroeher, H.
    Tabidze, M.
    Tagliente, G.
    Talman, R.
    Thörngren Engblom, Pia
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Trinkel, F.
    Uzikov, Yu.
    Valdau, Yu.
    Valetov, E.
    Vassiliev, A.
    Weidemann, C.
    Wronska, A.
    Wuestner, P.
    Zupranski, P.
    Zurek, M.
    Locking the Spin Precession in a Storage Ring2017In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 119, no 1, article id 014801Article in journal (Refereed)
    Abstract [en]

    This Letter reports the successful use of feedback from a spin polarization measurement to the revolution frequency of a 0.97 GeV= c bunched and polarized deuteron beam in the Cooler Synchrotron (COSY) storage ring in order to control both the precession rate (approximate to 121 kHz) and the phase of the horizontal polarization component. Real time synchronization with a radio frequency (rf) solenoid made possible the rotation of the polarization out of the horizontal plane, yielding a demonstration of the feedback method to manipulate the polarization. In particular, the rotation rate shows a sinusoidal function of the horizontal polarization phase (relative to the rf solenoid), which was controlled to within a 1 standard deviation range of sigma= 0.21 rad. The minimum possible adjustment was 3.7 mHz out of a revolution frequency of 753 kHz, which changes the precession rate by 26 mrad/s. Such a capability meets a requirement for the use of storage rings to look for an intrinsic electric dipole moment of charged particles.

  • 111. Herskind, B.
    et al.
    Hagemann, G. B.
    Dossing, Th
    Hansen, C. Ronn
    Schunck, N.
    Sletten, C.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Lagergren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Petrache, D.
    et al.,
    Light charged particles as gateway to hyperdeformation2007In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 38, no 4, p. 1421-1430Article in journal (Refereed)
    Abstract [en]

    The Euroball-IV gamma-detector array, equipped with the ancillary charged particle detector array DIAMANT was used to study the residues of the fusion reaction Ni-64 + Ni-64 double right arrow Ba-128 at E-beam. = 255 and 261 MeV, in an attempt to reach the highest angular momentum and verify the existence of predicted hyperdeformed rotational bands. No discrete hyperdeformed bands were identified, but nevertheless a breakthrough was obtained through a systematic search for rotational ridge structures with very large moments of inertia J(2) >= 100 h(2) MeV((-1)), in agreement with theoretical predictions for hyperdeformed shapes. Evidence for hyperdeformation was obtained by charged particle + gamma-ray gating, selecting triple correlated ridge structures in the continuum of each of the nuclei, Te-118, Xe-124 and Cs-124,Cs-125. In 7 additional nuclei, rotational ridges were also identified with J(2) = 71-77h(2) MeV((-1)), which most probably correspond to superdeformed shape. The angular distributions of the emitted charged particles show an excess in forward direction over expectations from pure compound evaporation, which may indicate that in-complete fusion plays an important role in the population of very elongated shapes.

  • 112. Herskind, B.
    et al.
    Hagemann, G. B.
    Sletten, G.
    Dossing, Th
    Hansen, C. Ronn
    Schunck, N.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Lagergren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    et al,
    Charged particle feeding of hyperdeformed nuclei in the A=118-126 region2006In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T125, p. 108-114Article in journal (Refereed)
    Abstract [en]

    A breakthrough was recently obtained in the analysis of the so-called Hyper-Long-HyperDeformed (HLHD) experiment made at the EUROBALL-IV gamma-detector array (EB). The Ni-64 + Ni-64 double right arrow Ba-128* fusion reaction was studied at E-beam = 255 and 261 MeV, reaching the highest angular momentum that the compound nuclei can accommodate. To date no discrete HD rotational bands have been identified. However, rotational patterns in the form of ridge-structures in three-dimensional (3D) rotational mapped spectra are identified with dynamic moments of inertia J((2)) ranging from 71 to 111h(2) MeV-1 in 12 different nuclei selected by charged particle- and/or gamma-gating. The four nuclei, Te-118, Cs-124, Cs-125 and Xe-124 found with moment of inertia J((2)) >= 100h(2) MeV-1, are most likely hyperdeformed, the remaining nuclei with smaller values of J((2)), are considered to be superdeformed, in qualitative agreement with recent theoretical calculations.

  • 113. Herzáň, A.
    et al.
    Juutinen, S.
    Auranen, K.
    Grahn, T.
    Greenlees, P. T.
    Hauschild, K.
    Jakobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. University of Jyvaskyla, Department of Physics, P.O. Box 35, Jyvaskyla, Finland.
    Jones, P.
    Julin, R.
    Ketelhut, S.
    Leino, M.
    Lopez-Martens, A.
    Nieminen, P.
    Nyman, M.
    Peura, P.
    Rahkila, P.
    Rinta-Antila, S.
    Ruotsalainen, P.
    Sandzelius, M.
    Sarén, J.
    Scholey, C.
    Sorri, J.
    Uusitalo, J.
    Detailed spectroscopy of Bi 1932015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 4Article in journal (Refereed)
    Abstract [en]

    An experiment aiming to study shape coexistence in Bi193 has been performed. Due to its transitional character, it has an exceptionally large number of structures identified close to the yrast line. Many new states have been found, significantly extending the previously known level scheme of Bi193, including several new rotational bands. The πi13/2 band was extended to Iπ=45/2+. The Iπ=31/2+ member of the πi13/2 band was found to de-excite also to a long-lived isomeric state. This isomeric state is located at 2350 keV and has a spin and parity of 29/2+. The half-life of the isomeric state was measured to be 85(3) μs and it decays via the emission of an 84 keV E2 transition. A level structure feeding this isomeric state was constructed. A low-energy, 49 keV transition has been identified to depopulate the (29/2-) isomeric state, which places it at an energy 2405 keV in the level scheme. This is the first time such a decay has been observed in the neutron-deficient Bi isotopes. A superdeformed band almost identical to that present in the neighboring isotope Bi191, based on the 1/2[651] Nilsson orbital, has also been identified.

  • 114. Hidvégi, A.
    et al.
    Eriksson, D.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Silverstein, S.
    Bohm, C.
    A high-speed data acquisition system for segmented Ge-detectors2007In: 2007 IEEE Nuclear Science Symposium Conference Record, IEEE , 2007, p. 536-537Conference paper (Refereed)
    Abstract [en]

    When using segmented Ge-detectors for gamma ray tracking it is necessary to determine the segment pulse shapes with high accuracy. A high-speed data acquisition system with many channels, high precision and with high sampling rate is required. There are also many other applications for such a system. Our system uses high performance FPGAs (Xilinx Virtex-V [2]) to cope with the data rates delivered by the high speed ADC chosen (Atmel 2Gsps, 10 bits) and to make all the data processing onboard in real time. Each board contains four such ADCs, which can either handle four channels up to full speed, or achieve higher sampling rates with interleaving. The boards can communicate with each other over different types of high-speed communication links. Control and monitoring is implemented with embedded processors. The processed result will be transmitted over Ethernet to final storage. The project introduces many challenging issues: signal integrity, ADC performance, interfacing ADCs to the FPGA, synchronisation of ADCs across the entire system, implementing flexible processing algorithms, high speed interconnection between boards and managing the significant heat generation. This is an ongoing project with interesting potentials for the future.

  • 115. Hodge, D.
    et al.
    Cullen, D. M.
    Taylor, M. J.
    Procter, M. G.
    Nieminen, P.
    Grahn, T.
    Greenlees, P. T.
    Hauschild, K.
    Herzan, A.
    Jakobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. University of Jyväskylä, Department of Physics, P.O. Box 35, Jyvaskyla, Finland.
    Jones, P.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Leino, M.
    Lopez-Martens, A.
    Partanen, J.
    Peura, P.
    Rahkila, P.
    Rinta-Antila, S.
    Ruotsalainen, P.
    Sandzelius, M.
    Sarén, J.
    Scholey, C.
    Sorri, J.
    Stolze, S.
    Uusitalo, J.
    Identification of a dipole band above the Iπ=31/2- isomeric state in Pb 1892015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 5Article in journal (Refereed)
    Abstract [en]

    A dipole band of six transitions built upon a firmly established Iπ=31/2- isomeric state has been identified in Pb189 using recoil-isomer tagging. This is the lightest odd-mass Pb nucleus in which a dipole band is known. The dipole nature of the new transitions has been confirmed through angular-intensity arguments. The evolution of the excitation energy and the aligned-angular momentum of the states in the new dipole band are compared with those of dipole bands in heavier, odd-mass lead isotopes. This comparison suggests that the new band in Pb189 is based upon a π[s1/2-2h9/2i13/2]11- - ν[i13/2+-1]13/2+ configuration. However, the increased aligned-angular momentum in Pb189 may suggest evidence for a reduced repulsive proton/neutron-hole interaction compared to dipole bands in the heavier mass isotopes.

  • 116. Hornillos, M. B. G.
    et al.
    O'Donnell, D.
    Simpson, J.
    Joss, D. T.
    Bianco, L.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Grahn, T.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jones, P.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Labiche, M.
    Leino, M.
    Nyman, M.
    Page, R. D.
    Paul, E. S.
    Petri, M.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Sapple, P. J.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Thomson, J.
    Uusitalo, J.
    gamma-ray spectroscopy approaching the limits of existence of atomic nuclei: A study of the excited states of Pt-168 and Pt-1692009In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 79, no 6Article in journal (Refereed)
    Abstract [en]

    Excited states in the N=90 and N=91 Pt nuclei have been investigated using the JUROGAM and GREAT spectrometers in conjunction with the RITU gas-filled separator. These nuclei were populated via the reactions Mo-92(Kr-78,2n) and Mo-94(Kr-78,3n) at 335 and 348 MeV, respectively. The recoil-decay tagging technique has been used to correlate prompt gamma radiation with the characteristic alpha decays of Pt-168 and Pt-169. A gamma-gamma analysis has allowed a level scheme for Pt-168 to be reported for the first time and the level scheme for Pt-169 to be extended. The excitation energies of the proposed positive-parity yrast states of Pt-168 are compared with calculations based on the interacting boson model and found to be in excellent agreement. These data show a continuation of the trend toward vibrational nuclei as the N=82 shell gap is approached. In addition, new excited states constituting two decay paths have been discovered in Pt-169.

    .

     

  • 117. Huang, Y.
    et al.
    Xiao, Z. G.
    Zhu, S. J.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Xu, Q.
    Cheng, W. J.
    Li, H. J.
    Lyu, L. M.
    Wang, R. S.
    Yan, W. H.
    Yi, H.
    Zhang, Y.
    Chen, Q. M.
    He, C. Y.
    Hu, S. P.
    Li, C. B.
    Li, H. W.
    Luo, P. W.
    Wu, X. G.
    Wu, Y. H.
    Zheng, Y.
    Zhong, J.
    High-spin structures in the Xe-129 nucleus2016In: Physical Review C, ISSN 2469-9985, Vol. 93, no 6, article id 064315Article in journal (Refereed)
    Abstract [en]

    High-spin states in the Xe-129 nucleus are studied with the reaction Sn-124(Be-9,4n) at a beam energy of 36 MeV. The level scheme is extended significantly. For the positive-parity band, the alpha = +1/2 and the alpha = -1/2 signature components are combined to form a complete band structure based on the 3/2(+) state with spin and parity up to 21/2(+). For the negative-parity band based on the 11/2(-) state, the alpha = +1/2 signature component is newly established and both the alpha = +1/2 and the alpha = -1/2 signature components also form a complete band structure up to the 35/2(-) state. The positive-and negative-parity bands are proposed to originate from nu d(3/2) 3/2(+)[402] and nu h(11/2)11/2(-)[505] Nilsson configurations, respectively. A backbending is observed in the negative-parity band, which originates from the alignments of two h(11/2) protons according to crank shell model calculations. Based on the total Routhian surface and quasiparticle triaxial rotor model calculations, the negative-parity band is interpreted as a triaxially deformed shape with gamma approximate to -30 degrees, while the positive-parity band is associated with. softness, in accordance with previous studies. In the high-spin states, three decoupled bands and one oblate band with gamma approximate to -60 degrees are newly identified. The systematics and other characteristics of these bands are discussed.

  • 118. Hueyuek, Tayfun
    et al.
    Di Nitto, Antonio
    Jaworski, Grzegorz
    Gadea, Andres
    Valiente-Dobon, Jose Javier
    Nyberg, Johan
    Palacz, Marcin
    Soederstroem, Paer-Anders
    Jose Aliaga-Varea, Ramon
    de Angelis, Giacomo
    Ataç, Ayşe
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Collado, Javier
    Domingo-Pardo, Cesar
    Egea, Francisco Javier
    Erduran, Nizamettin
    Ertuerk, Sefa
    de France, Gilles
    Gadea, Rafael
    Gonzalez, Vicente
    Herrero-Bosch, Vicente
    Kaskas, Ayse
    Modamio, Victor
    Moszynski, Marek
    Sanchis, Enrique
    Triossi, Andrea
    Wadsworth, Robert
    Conceptual design of the early implementation of the NEutron Detector Array (NEDA) with AGATA2016In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 52, no 3, article id 55Article in journal (Refereed)
    Abstract [en]

    The NEutron Detector Array (NEDA) project aims at the construction of a new high-efficiency compact neutron detector array to be coupled with large gamma-ray arrays such as AGATA. The application of NEDA ranges from its use as selective neutron multiplicity filter for fusion-evaporation reaction to a large solid angle neutron tagging device. In the present work, possible configurations for the NEDA coupled with the Neutron Wall for the early implementation with AGATA has been simulated, using Monte Carlo techniques, in order to evaluate their performance figures. The goal of this early NEDA implementation is to improve, with respect to previous instruments, efficiency and capability to select multiplicity for fusion-evaporation reaction channels in which 1, 2 or 3 neutrons are emitted. Each NEDA detector unit has the shape of a regular hexagonal prism with a volume of about 3.23 l and it is filled with the EJ301 liquid scintillator, that presents good neutron-gamma discrimination properties. The simulations have been performed using a fusion-evaporation event generator that has been validated with a set of experimental data obtained in the Ni-58 + Fe-56 reaction measured with the Neutron Wall detector array.

  • 119. Häfner, G.
    et al.
    Moschner, K.
    Blazhev, A.
    Boutachkov, P.
    Davies, P. J.
    Wadsworth, R.
    Ameil, F.
    Baba, H.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Dewald, M.
    Doornenbal, P.
    Faestermann, T.
    Gengelbach, A.
    Gerl, J.
    Gernhaüser, R.
    Go, S.
    Górska, M.
    Grawe, H.
    Gregor, E.
    Hotaka, H.
    Isobe, T.
    Jenkins, D. G.
    Jolie, J.
    Jung, H. S.
    Kojouharov, I.
    Kurz, N.
    Lewitowicz, M.
    Lorusso, G.
    Lozeva, R.
    Merchan, E.
    Naqvi, F.
    Nishibata, H.
    Nishimura, D.
    Nishimura, S.
    Pietralla, N.
    Schaffner, H.
    Söderström, P. -A
    Steiger, K.
    Sumikama, T.
    Taprogge, J.
    Thöle, P.
    Watanbe, H.
    Warr, N.
    Werner, V.
    Xu, Z. Y.
    Yagi, A.
    Yoshinaga, K.
    Zhu, Y.
    Properties of γ-decaying isomers in the Sn 100 region populated in fragmentation of a Xe 124 beam2019In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 100, no 2, article id 024302Article in journal (Refereed)
    Abstract [en]

    A systematic study was performed of microsecond γ-decaying isomers around Sn100 produced in a fragmentation reaction of a Xe124 beam at 345 MeV/u at the Radioactive Ion Beam Factory of the RIKEN Nishina Center in Saitama, Japan. Half-lives of isomeric states in that region were remeasured allowing us to improve the currently available experimental information. Reduced transition probabilities were deduced and compared to shell-model calculations in various model spaces. The recently reported low-energy transitions in Rh92 and Ag96 were remeasured with improved precision. Additionally, experimental information on isomeric ratios, including five new ones, were extracted and compared to a previous experimental study and the sharp cutoff model of fragmentation reaction.

  • 120. Id Betan, R.
    et al.
    Dussel, G. G.
    Liotta, Roberta
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Assessment of the importance of the pairing interaction in the continuum2008In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 78, no 4, p. 044325-Article in journal (Refereed)
    Abstract [en]

    A pairing interaction fitted to be applied in nuclei with active particles moving close to the continuum threshold or even immersed in the continuum itself is introduced. It is found that the effects of the nonresonant continuum upon physically meaningful quantities is unimportant. We applied the theory to heavy tin isotopes and good agreement between theory and the very few available experimental data is found.

  • 121.
    Id Betan, Rodolfo M
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Sandulescu, N.
    Vertse, T.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Complex shell model representation including antibound states2005In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 72, no 5, p. 054322-Article in journal (Refereed)
    Abstract [en]

    A generalization of the complex shell model formalism is presented that includes antibound states in the basis. These states, together with bound states, Gamow states, and the continuum background, represented by properly chosen scattering waves, form a representation in which all states are treated on the same footing. Two-particle states are evaluated within this formalism, and observable two-particle resonances are defined. The formalism is illustrated in the well-known case of Li-11 in its bound ground state and in Ca-70(g.s.), which is also bound. Both cases are found to have a halo structure. These halo structures are described within the generalized complex shell model. We investigated the formation of two-particle resonances in these nuclei, but no evidence of such resonances was found.

  • 122. Ideguchi, E.
    et al.
    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.
    Lagergren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Eeckhaudt, S.
    Grahn, T.
    Greenlees, P.
    Julin, R.
    Juutinen, S.
    Kettunen, H.
    Leino, M.
    Leppanen, A. P.
    Nieminen, P.
    Nyman, M.
    Pakarinen, J.
    Rahkila, P.
    Scholey, C.
    Uusitalo, J.
    Joss, D. T.
    Paul, E. S.
    Wiseman, D. R.
    Wadsworth, R.
    Afanasjev, A. V.
    Ragnarsson, I.
    High-spin intruder band in In-1072010In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 81, no 3, p. 034303-Article in journal (Refereed)
    Abstract [en]

    High-spin states in the neutron-deficient nucleus In-107 were studied via the Ni-58(Cr-52,3p) reaction. In-beam gamma rays were measured using the JUROGAM detector array. A rotational cascade consisting of ten gamma-ray transitions, which decays to the 19/2(+) level at 2.002 MeV, was observed. The band exhibits the features typical for smooth terminating bands that also appear in rotational bands of heavier nuclei in the A similar to 100 region. The results are compared with total Routhian surface and cranked Nilsson-Strutinsky calculations.

  • 123. Ideguchi, E
    et al.
    Niikura, M
    Ishida, C
    Fukuchi, T
    Baba, H
    Hokoiwa, N
    Iwasaki, H
    Koike, T
    Komatsubara, T
    Kubo, T
    Kurokawa, M
    Michimasa, S
    Miyakawa, K
    Morimoto, K
    Ohnishi, T
    Ota, S
    Ozawa, A
    Shimoura, S
    Suda, T
    Tarnaki, M
    Tanihata, I
    Wakabayashi, Y
    Yoshida, K
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Study of high-spin states in the Ca-48 region by using secondary fusion reactions2005In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 25, p. 429-430Article in journal (Refereed)
    Abstract [en]

    An in-beam gamma-ray spectroscopy study, following a fusion reaction induced by a neutronrich secondary beam, Ar-46 + Be-9, is presented. A low-energy secondary beam of Ar-46 at similar to 5 MeV/A was developed in order to induce fusion reactions. Gamma-gamma coincidence and excitation function analysis was performed to study high-spin states in the vicinity of Ca-48, Ti49-52.

  • 124.
    Jakobsson, U.
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Uusitalo, J.
    Auranen, K.
    Badran, H.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cox, D. M.
    Grahn, T.
    Greenlees, P. T.
    Julin, R.
    Juutinen, S.
    Herzan, A.
    Konki, J.
    Leino, M.
    Mallaburn, M.
    Pakarinen, J.
    Papadakis, P.
    Partanen, J.
    Rahkila, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Stolze, S.
    Spectroscopy of Low-lying States in Neutron-deficient Astatine and Francium Nuclei2015In: NUCLEAR STRUCTURE AND DYNAMICS '15, American Institute of Physics (AIP), 2015, article id UNSP 030014Conference paper (Refereed)
    Abstract [en]

    Low-lying states in neutron-deficient astatine and francium nuclei have been studied by means of in-beam and delayed spectroscopy. The 13/2(+) state has been observed in francium nuclei with a similar down-sloping trend as in neighbouring astatine and bismuth isotopes, as a function of decreasing neutron number. A systematic trend can also now be seen for the 1/2(+) state both in astatine and francium nuclei, where the level energy decreases steeply as a function of neutron number when moving further away from the neutron shell closure. This trend is very similar between astatine nuclei and their francium isotones. Moreover, shape coexistence has been observed between the 13/2(+) state and the spherical 9/2(-) ground state in Fr-203 and Fr-205.

  • 125. Jakobsson, U.
    et al.
    Uusitalo, J.
    Juutinen, S.
    Leino, M.
    Nieminen, P.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jones, P.
    Julin, R.
    Ketelhut, S.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Nyman, M.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Prompt and delayed spectroscopy of At-1992010In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 82, no 4, p. 044302-Article in journal (Refereed)
    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.

  • 126. Jentschel, M.
    et al.
    Blanc, A.
    de France, G.
    Koster, U.
    Leoni, S.
    Mutti, P.
    Simpson, G.
    Soldner, T.
    Ur, C.
    Urban, W.
    Ahmed, S.
    Astier, A.
    Augey, L.
    Back, T.
    Baczyk, P.
    Bajoga, A.
    Balabanski, D.
    Belgya, T.
    Benzoni, G.
    Bernards, C.
    Biswas, D. C.
    Bocchi, G.
    Bottoni, S.
    Britton, R.
    Bruyneel, B.
    Burnett, J.
    Cakirli, R. B.
    Carroll, R.
    Catford, W.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Celikovic, I.
    Cieplicka-Oryn'czak, N.
    Clement, E.
    Cooper, N.
    Crespi, F.
    Csatlos, M.
    Curien, D.
    Czerwinski, M.
    Danu, L. S.
    Davies, A.
    Didierjean, F.
    Drouet, F.
    Duche'ne, G.
    Ducoin, C.
    Eberhardt, K.
    Erturk, S.
    Fraile, L. M.
    Gottardo, A.
    Grente, L.
    Grocutt, L.
    Guerrero, C.
    Guinet, D.
    Hartig, A. -L
    Henrich, C.
    Ignatov, A.
    Ilieva, S.
    Ivanova, D.
    John, B. V.
    John, R.
    Jolie, J.
    Kisyov, S.
    Krticka, M.
    Konstantinopoulos, T.
    Korgul, A.
    Krasznahorkay, A.
    Kroell, T.
    Kurpeta, J.
    Kuti, I.
    Lalkovski, S.
    Larijani, C.
    Leguillon, R.
    Lica, R.
    Litaize, O.
    Lozeva, R.
    Magron, C.
    Mancuso, C.
    Martinez, E. Ruiz
    Massarczyk, R.
    Mazzocchi, C.
    Melon, B.
    Mengoni, D.
    Michelagnoli, C.
    Million, B.
    Mokry, C.
    Mukhopadhyay, S.
    Mulholland, K.
    Nannini, A.
    Napoli, D. R.
    Olaizola, B.
    Orlandi, R.
    Patel, Z.
    Paziy, V.
    Petrache, C.
    Pfeiffer, M.
    Pietralla, N.
    Podolyak, Z.
    Ramdhane, M.
    Redon, N.
    Regan, P.
    Regis, J. M.
    Regnier, D.
    Oliver, R. J.
    Rudigier, M.
    Runke, J.
    Rzaca-Urban, T.
    Saed-Samii, N.
    Salsac, M. D.
    Scheck, M.
    Schwengner, R.
    Sengele, L.
    Singh, P.
    Smith, J.
    Stezowski, O.
    Szpak, B.
    Thomas, T.
    Thuerauf, M.
    Timar, J.
    Tom, A.
    Tomandl, I.
    Tornyi, T.
    Townsley, C.
    Tuerler, A.
    Valenta, S.
    Vancraeyenest, A.
    Vandone, V.
    Vanhoy, J.
    Vedia, V.
    Warr, N.
    Werner, V.
    Wilmsen, D.
    Wilson, E.
    Zerrouki, T.
    Zielinska, M.
    EXILL - a high-efficiency, high-resolution setup for gamma-spectroscopy at an intense cold neutron beam facility2017In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 12, article id P11003Article in journal (Refereed)
    Abstract [en]

    In the EXILL campaign a highly efficient array of high purity germanium (HPGe) detectors was operated at the cold neutron beam facility PF1B of the Institut Laue-Langevin (ILL) to carry out nuclear structure studies, via measurements of gamma-rays following neutron-induced capture and fission reactions. The setup consisted of a collimation system producing a pencil beam with a thermal capture equivalent flux of about 10(8) ns(-1)cm(2) at the target position and negligible neutron halo. The targetwas surrounded by an array of eight to ten anti-Compton shielded EXOGAMClover detectors, four to six anti-Compton shielded large coaxial GASP detectors and two standard Clover detectors. For a part of the campaign the array was combined with 16 LaBr3:(Ce) detectors from the FATIMA collaboration. The detectorswere arranged in an array of rhombicuboctahedron geometry, providing the possibility to carry out very precise angular correlation and directional-polarization correlation measurements. The triggerless acquisition system allowed a signal collection rate of up to 6 x 10(5) Hz. The data allowed to set multi-fold coincidences to obtain decay schemes and in combination with the FATIMA array of LaBr3:(Ce) detectors to analyze half-lives of excited levels in the pico-to microsecond range. Precise energy and efficiency calibrations of EXILL were performed using standard calibration sources of Ba-133, Co-60 and Eu-152 as well as data from the reactions Al-27(n, gamma)Al-28 and Cl-35(n,gamma)Cl-36 in the energy range from 30 keV up to 10MeV.

  • 127. 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.

  • 128. Jia, L. Y.
    et al.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Generalized-seniority pattern and thermal properties in even Sn isotopes2016In: PHYSICAL REVIEW C, ISSN 2469-9985, Vol. 94, no 4, article id 044312Article in journal (Refereed)
    Abstract [en]

    Even tin isotopes of mass number A = 108-124 are calculated with realistic interactions in the generalized-seniority approximation of the nuclear shell model. For each nucleus, we compute the lowest 10 000 states (5000 of each parity) up to around 8 MeV in excitation energy, by allowing as many as four broken pairs. The lowest 50 eigen energies of each parity are compared with the exact results of the large-scale shell-model calculation. The wave functions of the midshell nuclei show a clear pattern of the stepwise breakup of condensed coherent pairs with increasing excitation energy. We also compute in the canonical ensemble the thermal properties-level density, entropy, and specific heat-in relation to the thermal pairing phase transition.

  • 129.
    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.

  • 130.
    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.

  • 131. 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.

  • 132. 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.

  • 133. Joss, D. T.
    et al.
    Amzal, N.
    Appelbe, D. E.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hadinia, Baharak
    Lagergren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Probing structural changes in the very neutron-deficient Os isotopes with recoil-decay tagging2005In: Journal of Physics G: Nuclear and Particle Physics, ISSN 0954-3899, E-ISSN 1361-6471, Vol. 31, no 10, p. S1593-S1598Article in journal (Refereed)
    Abstract [en]

    In recent years, the exploitation of the iecoil-decay tagging (RDT) technique with,large arrays of germanium detectors has revealed much information about the structure of heavy nuclei approaching the proton drip line. The yrast bands of the N <= 93 osmium isotopes have been identified in a campaign of tagging experiments using various spectrometer arrays coupled to the RITU gas-filled separator based at the University of Jyvaskyla. Trends in the yrast state excitation energies have indicated a transition from gamma-soft triaxial to near-spherical shapes with decreasing neutron number. Recent experimental results for Os-162 obtained with the JUROGAM and GREAT spectrometers also indicate the importance of configurations involving the h(9/2) neutron states as the N = Z 82 shell gaps are approached.

  • 134. Joss, D. T.
    et al.
    Darby, I. G.
    Page, R. D.
    Uusitalo, J.
    Eeckhaudt, S.
    Grahn, T.
    Greenlees, P. T.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Leino, M.
    Leppänen, A. -P
    Nyman, M.
    Pakarinen, J.
    Rahkila, P.
    Sarén, J.
    Scholey, C.
    Steer, A.
    Cannon, A. J.
    Stevenson, P. D.
    Al-Khalili, J. S.
    Ertürk, S.
    Venhart, M.
    Gall, B.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Simpson, J.
    Probing the limit of nuclear existence: Proton emission from Re-1592006In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 641, no 1, p. 34-37Article in journal (Refereed)
    Abstract [en]

    The observation of the new nuclide Re-159(75)84 provides important insights into the evolution of single-particle structure and the mass surface in heavy nuclei beyond the proton drip line. This nuclide, 26 neutrons away from the nearest stable rhenium isotope, was synthesised in the reaction Cd-106(Ni-58, p4n) and identified via its proton radioactivity using the RITU gas-filled separator and the GREAT focal-plane spectrometer. Comparisons of the measured proton energy (E-p = 1805 +/- 20 keV) and decay half-life (t(1/2) = 21 +/- 4 mu s) with values calculated using the WKB method indicate that the proton is emitted from an h(11/2) state. The implications of these results for future experimental investigations into even more proton unbound nuclei using in-flight separation techniques are considered.

  • 135. Joss, D. T.
    et al.
    Dracoulis, G. D.
    Higgins, E.
    Lewis, M.
    Thomson, J.
    Lane, G. J.
    Page, R. D.
    Simpson, J.
    Bianco, L.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Darby, I. G.
    Davidson, P. M.
    Eeckhaudt, S.
    Erturk, S.
    Fabricius, B.
    Gomez-Hornillos, M. B.
    Grahn, T.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jakobsson, U.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Leino, M.
    Nieminen, P.
    Nyman, M.
    Pakarinen, J.
    Paul, E. S.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Sapple, P. J.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Uusitalo, J.
    Evolving collective structures in the transitional nuclei W-162 and W-1642016In: PHYSICAL REVIEW C, ISSN 2469-9985, Vol. 93, no 2, article id 024307Article in journal (Refereed)
    Abstract [en]

    Excited states in the neutron-deficient nuclides(74)(162)W(88) and W-164(74)90 were investigated by using the gamma-ray spectrometer Jurogam. A change in structure is apparent from the first rotational alignments in W-162 and W-164, whose rotationally aligned bands are interpreted as nu(h(9/2))(2) and nu(i(13/2))(2) configurations, respectively. The level schemes have been extended using recoil (-decay) correlations with the observation of excited collective structures. Configuration assignments have been made on the basis of comparisons of the deduced aligned angular momentum, as a function of rotational frequency, with the predictions of the cranked shell model.

  • 136. Joss, D. T.
    et al.
    Lagergren, K.
    Thomson, J.
    Appelbe, D. E.
    Barton, C. J.
    Bianco, L.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Darby, I. G.
    Grahn, T.
    Eeckhaudt, S.
    Ertürk, S.
    Gomez-Hornillos, M. B.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Kettunen, H.
    Labiche, M.
    Leino, M.
    Leppänen, A. -P
    Nieminen, P.
    Nyman, M.
    O'Donnell, D.
    Page, R. D.
    Pakarinen, J.
    Paul, E. S.
    Perkowski, J.
    Rahkila, P.
    Sandzelius, M.
    Sapple, P. J.
    Sarén, J.
    Scholey, C.
    Simpson, J.
    Sorri, J.
    Uusitalo, J.
    Venhart, M.
    Warner, D. D.
    Wiseman, D. R.
    Wyss, Ramon A.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    The influence of quasineutron configurations on 161Ta and nearby odd-A nuclei2011In: AIP Conf. Proc., 2011, p. 43-48Conference paper (Refereed)
    Abstract [en]

    Several strongly coupled bands in the neutron-deficient nucleus 161Ta have been identified and quasiparticle configuration assignments have been made on the basis of rotational alignments and cranked shell model calculations. The level scheme elucidated for 161Ta highlights the competition between the ν(h 9/2) and ν(i 13/2) orbitals to form the yrast spectrum. The band structures in 161Ta also provide new insights into the structural features of other heavy odd-A nuclei populated with much lower reaction cross sections in this region at the proton drip line.

  • 137. Joss, D. T.
    et al.
    Page, R. D.
    Herzán, A.
    Donosa, L.
    Uusitalo, J.
    Carroll, R. J.
    Darby, I. G.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Eeckhaudt, S.
    Grahn, T.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jakobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. 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 158W2017In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 772, p. 703-707Article in journal (Refereed)
    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.

  • 138. 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.

  • 139. Joss, D. T.
    et al.
    Simpson, J.
    Appelbe, D. E.
    Lagergren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Barton, C. J.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Eeckhaudt, S.
    Grahn, T.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Kettunen, H.
    Leino, M.
    Leppanen, A. P.
    Nieminen, P.
    Page, R. D.
    Pakarinen, J.
    Paul, E. S.
    Perkowski, J.
    Rahkila, P.
    Riley, M. A.
    Scholey, C.
    Uusitalo, J.
    Van de Vel, K.
    Warner, D. D.
    Wiseman, D. R.
    Yrast structures in the light Pt isotopes Pt169-1732005In: Journal of Physics G: Nuclear and Particle Physics, ISSN 0954-3899, E-ISSN 1361-6471, Vol. 31, no 10, p. S1715-S1718Article in journal (Refereed)
    Abstract [en]

    The exploitation of the recoil-decay tagging (RDT) technique has reinvigorated experimental investigations of the shape coexistence phenomenon in heavy neutron-deficient nuclei. In a recent experiment using the JUROGAM and GREAT spectrometers in conjunction with the RITU gas-filled separator, excited states have been investigated in the light platinum isotopes. In addition to extending the yrast sequences in Pt-170 and Pt-172, the first observation of excited states in the odd-N isotopes, Pt-169 and Pt-173, is reported. The bands are discussed in terms of trends in level excitation energies as a function of neutron number.

  • 140. Jungclaus, A.
    et al.
    Caceres, L.
    Gorska, M.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    et al,
    Observation of isomeric decays in the r-process waiting-point nucleus Cd-130(82)2007In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 99, no 13Article in journal (Refereed)
    Abstract [en]

    The gamma decay of excited states in the waiting-point nucleus Cd-130(82) has been observed for the first time. An 8(+) two-quasiparticle isomer has been populated both in the fragmentation of a Xe-136 beam as well as in projectile fission of U-238, making Cd-130 the most neutron-rich N=82 isotone for which information about excited states is available. The results, interpreted using state-of-the-art nuclear shell-model calculations, show no evidence of an N=82 shell quenching at Z=48. They allow us to follow nuclear isomerism throughout a full major neutron shell from Cd-98(50) to Cd-130(82) and reveal, in comparison with Ni-76(48) one major proton shell below, an apparently abnormal scaling of nuclear two-body interactions.

  • 141.
    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.

  • 142.
    Karlgren, Daniel
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Mixing of wave functions at different shapes: A study of Alpha Decay Hindrance Factors within the Generator Coordinate MethodManuscript (preprint) (Other academic)
  • 143. Ketelhut, S.
    et al.
    Greenlees, P. T.
    Ackermann, D.
    Antalic, S.
    Clement, E.
    Darby, I. G.
    Dorvaux, O.
    Drouart, A.
    Eeckhaudt, S.
    Gall, B. J. P.
    Goergen, A.
    Grahn, T.
    Gray-Jones, C.
    Hauschild, K.
    Herzberg, R. -D
    Hessberger, F. P.
    Jakobsson, U.
    Jones, G. D.
    Jones, P.
    Julin, R.
    Juutinen, S.
    Khoo, T. -L
    Korten, W.
    Leino, M.
    Leppaenen, A. -P
    Ljungvall, J.
    Moon, S.
    Nyman, M.
    Obertelli, A.
    Pakarinen, J.
    Parr, E.
    Papadakis, P.
    Peura, P.
    Piot, J.
    Pritchard, A.
    Rahkila, P.
    Rostron, D.
    Ruotsalainen, P.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Steer, A.
    Sulignano, B.
    Theisen, Ch.
    Uusitalo, J.
    Venhart, M.
    Zielinska, M.
    Bender, M.
    Heenen, P. -H
    gamma-Ray Spectroscopy at the Limits: First Observation of Rotational Bands in Lr-2552009In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 102, no 21, p. 212501-Article in journal (Refereed)
    Abstract [en]

    The rotational band structure of Lr-255 has been investigated using advanced in-beam gamma-ray spectroscopic techniques. To date, Lr-255 is the heaviest nucleus to be studied in this manner. One rotational band has been unambiguously observed and strong evidence for a second rotational structure was found. The structures are tentatively assigned to be based on the 1/2(-)[521] and 7/2(-)[514] Nilsson states, consistent with assignments from recently obtained alpha decay data. The experimental rotational band dynamic moment of inertia is used to test self-consistent mean-field calculations using the Skyrme SLy4 interaction and a density-dependent pairing force.

  • 144. 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).

  • 145. Kovtun, Oleksiy
    et al.
    Tioukine, Valeri
    Surzhykov, Andrey
    Yerokhin, Vladimir A.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Tashenov, Stanislav
    Spin-orbit interaction in bremsstrahlung and its effect on the electron motion in a strong Coulomb field2015In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 92, no 6, article id 062707Article in journal (Refereed)
    Abstract [en]

    Linear polarization of bremsstrahlung x rays produced in collisions of longitudinally polarized 2.1-MeV electrons with gold atoms was studied using the Compton scattering technique. We observed that the angle of x-ray polarization is strongly correlated with the incoming electron polarization. This correlation reveals the dominance of the spin-orbit interaction in bremsstrahlung and indicates a striking effect of the electron spin on the electron motion in a strong Coulomb field. The results confirm the validity of the theoretical predictions in a computationally challenging energy regime.

  • 146. Kovtun, Oleksiy
    et al.
    Tioukine, Valery
    Surzhykov, Andrey
    Yerokhin, Vladimir A.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Tashenov, Stanislav
    Strong effect of the electron spin on bremsstrahlung observed in the relativistic regime2015In: XXIX INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC, AND ATOMIC COLLISIONS (ICPEAC2015), PTS 1-12, Institute of Physics Publishing (IOPP), 2015, article id UNSP 052089Conference paper (Refereed)
    Abstract [en]

    We have studied bremsstrahlung produced by polarized 2.1 MeV electrons colliding with a thin gold target. We have observed a strong correlation between the orientation of the electron spin and the angle of x-ray linear polarization at the x-ray high energy tip region. This indicates a dominance of the spin-orbit interaction in bremsstrahlung.

  • 147.
    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.

  • 148.
    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.

  • 149. 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.

  • 150.
    Lenisa, P.
    et al.
    Univ Ferrara, I-44122 Ferrara, Italy.;INFN, I-44122 Ferrara, Italy..
    Thörngren Engblom, Pia
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Zupranski, P.
    Natl Ctr Nucl Res, PL-00681 Warsaw, Poland..
    Low-energy spin-physics experiments with polarized beams and targets at the COSY storage ring2019In: EPJ TECHNIQUES AND INSTRUMENTATION, ISSN 2195-7045, Vol. 6, no 1, article id 2Article in journal (Refereed)
    Abstract [en]

    A low-energy spin-physics program is being developed at the COSY storage ring. To support the planned experimental activities, several experimental tools for polarized beams and targets have been developed. The paper presents the physics case and the readiness of the setup for its realization.

1234567 101 - 150 of 322
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