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  • 1.
    Andgren, Karin
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    gamma-ray spectroscopy of At-1972008In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 78, no 4, p. 044328-1-044328-8Article in journal (Refereed)
    Abstract [en]

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

  • 2. Axelsson, A
    et al.
    Nyberg, J
    Atac, A
    Bergstrom, M H
    Herskind, B
    de Angelis, G
    Back, T
    Bazzacco, D
    Bracco, A
    Camera, F
    Cederwall, B
    Fahlander, C
    Huijnen, J H
    Lunardi, S
    Million, B
    Napoli, D R
    Persson, J
    Piiparinen, M
    Alvarez, C R
    Sletten, G
    Varmette, P G
    Weiszflog, M
    Excited superdeformed band in Eu-1431999In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 6, no 2, p. 175-183Article in journal (Refereed)
    Abstract [en]

    A new superdeformed band has been discovered in a EUROBALL experiment and assigned to Eu-143. It has a maximum intensity of 35% of the Eu-143 yrast superdeformed band and the transition energies of the two bands are very similar. Based on comparison with cranked shell model calculations the new band is tentatively assigned the high-N intruder configuration pi 6(2)nu 7(0) and the parity and signature quantum numbers (pi, alpha) = (-1, +1/2). In addition to the already known high-energy transition at 3361 keV another discrete line at 2715 keV was found to be in coincidence with the yrast superdeformed band. However, it was not possible to connect the decay out of either of the superdeformed bands to, known normally deformed states.

  • 3. Bark, R A
    et al.
    Tormanen, S
    Bäck, Torbjörn
    Cederwall, Bo
    Odegard, S W
    Cocks, J F C
    Helariutta, K
    Jones, P
    Julin, R
    Juutinen, S
    Kankaanpaa, H
    Kettunen, H
    Kuusiniemi, P
    Leino, M
    Muikku, M
    Rahkila, P
    Savelius, A
    Bandcrossings in Os-1711999In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 646, no 4, p. 399-413Article in journal (Refereed)
    Abstract [en]

    The nucleus Os-171 has been populated using the reaction Sn-116(Ni-58,2pn). Four new bands are identified, and the previously known bands are extended in spin, to a maximum of 53/2 (h) over bar. One- and three-quasiparticle configurations are identified, and beta, gamma, and octupole configurations are assigned tentatively. The effects of a possible intruder configuration on the negative parity bands are tested using band-mixing calculations.

  • 4. Bark, R A
    et al.
    Tormanen, S
    Bäck, Torbjörn
    Cederwall, Bo
    Odegard, S W
    Cocks, J F C
    Helariutta, K
    Jones, P
    Julin, R
    Juutinen, S
    Kankaanpaa, H
    Kettunen, H
    Kuusiniemi, P
    Leino, M
    Muikku, M
    Rahkila, P
    Savelius, A
    Bergstrom, M
    Ingebretsen, F
    Maj, A
    Mattiuzzi, M
    Mueller, W
    Riedinger, L L
    Saitoh, T
    Tjom, P O
    Coexistence of triaxial and prolate shapes in Ir-1711999In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 657, no 2, p. 113-133Article in journal (Refereed)
    Abstract [en]

    Excited states in Ir-171 have been observed for the first time. Gamma-rays were assigned to the nucleus by the recoil-decay tagging method, The ground-state band has a structure consistent with an h(11/2) proton coupled to a core of large triaxial deformation. At high spins, a bandcrossing occurs which is interpreted as a change in shape to a prolate deformation, Band-mixing calculations are performed for Ir171-175. These show that shape-coexistence between triaxial and prolate states in these nuclei follows the same systematics found in their Pt and Os neighbours. The systematics are also compared with deformations calculated for Ir171-179 using the code "Ultimate Cranker". Dipole bands were also observed, but tilted axis cranking calculations suggest that they are associated with a collective rotation.

  • 5.
    Bäck, Torbjörn
    KTH, Superseded Departments, Physics.
    Spectroscopy of neutron deficient nuclei in the A=90 and A=170 mass regions2002Doctoral thesis, comprehensive summary (Other scientific)
  • 6.
    Bäck, Torbjörn
    KTH, Superseded Departments, Physics.
    Superdeformed states in A90 nuclei1999Licentiate thesis, comprehensive summary (Other scientific)
  • 7.
    Bäck, Torbjörn
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederkall, J.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    van der Marel, J.
    Molnar, J.
    Novak, D.
    Sohler, D.
    Steen, M.
    Uhlen, P.
    A TOF-PET system for educational purposes2002In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 477, no 03-jan, p. 82-87Article in journal (Refereed)
    Abstract [en]

    A TOF-PET system has been designed and constructed for educational purposes. The aim of this system is to demonstrate the possibilities of positron emission tomography in general and the time-of-flight method in particular to the students of various courses at the Royal Institute of Technology, Stockholm, Sweden. The set-up consists of 48 small BaF2 crystals coupled to fast photomultipliers placed in a ring geometry. The signals of the photomultipliers are fed into fast constant fraction discriminators (CFD). The outputs of these are directed to a specially designed logic VME unit. which combines the CFD signals of 6 neighbouring channels to one signal by adding a different delay to each channel. The logic circuitry produces a prompt pulse for each event that serves as the start pulse for the 8-channel fast TDC. The delayed pulses act as the stop pulses for the TDC. In a computer. the measured times are converted into information about which the photomultipliers fired with the difference in the time of flight. The set-up is described and the results are presented.

  • 8.
    Bäck, Torbjörn
    et al.
    KTH, Superseded Departments, Physics.
    Cederkäll, Joakim
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    van der Marel, J
    Molnar, J
    Novak, D
    Sohler, D
    Steen, M
    Uhlen, P
    An educational tool for demonstrating the TOF-PET technique2001In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 471, no 1-2, p. 200-204Article in journal (Refereed)
    Abstract [en]

    A detector system for positron emission tomography with time-of-flight capability has been built to serve as an educational tool for undergraduate students. The set-up consists of 48 BaF2 scintillator crystals, each coupled to a fast photo-multiplier tube, mounted in a circular geometry. The analogue detector pulses are handled by fast constant fraction discriminators. A dedicated unit reduces the 48 channels to eight channels via delay-fine encoding, and the signals are then fed to an eight channel fast time-to-digital converter. A VME processor sorts the events and sends them to a workstation where the coincident events are extracted. The time resolution of the detectors together with fast VME based electronics allows for time-of-flight measurements to improve on the signal-to-noise ratio in the, reconstructed images. The system can be used for different types of exercises for the students, varying from the fundamentals of scintillator detectors to advanced image reconstruction. The set-up is described and some results are presented. (C) 2001 Elsevier Science B.V. All rights reserved.

  • 9.
    Bäck, Torbjörn
    et al.
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Lagergren, Karin
    KTH, Superseded Departments, Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Greenlees, P
    Jenkins, D
    Jones, P
    Joss, T
    Julin, R
    Juutinen, S
    Keenan, A
    Kettunen, H
    Kuusiniemi, P
    Leino, M
    Leppanen, P
    Muikku, M
    Nieminen, P
    Pakarinen, J
    Rahkila, P
    Uusitalo, J
    Spectroscopy of the neutron-deficient nuclide Pt-1712003In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 17, no 1, p. 1-5Article in journal (Refereed)
    Abstract [en]

    A number of previously unobserved gamma-rays emitted from the neutron-deficient nuclide Pt-171 have been identified using the recoil decay tagging technique. The level scheme has been updated using information from gamma-gamma coincidences and angular distribution measurements. To further confirm the assignments of the gamma-rays to Pt-171, the events were correlated with the alpha-decay of the daughter nucleus Os-167.

  • 10.
    Bäck, Torbjörn
    et al.
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Lagergren, Karin
    KTH, Superseded Departments, Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Karlgren, Daniel
    KTH, Superseded Departments, Physics.
    Greenlees, P
    Jenkins, D
    Jones, P
    Joss, T
    Julin, R
    Juutinen, S
    Keenan, A
    Kettunen, H
    Kuusiniemi, P
    Leino, M
    Leppanen, P
    Muikku, M
    Nieminen, P
    Pakarinen, J
    Rahkila, P
    Uusitalo, J
    First observation of gamma-rays from the proton emitter Au-1712003In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 16, no 4, p. 489-494Article in journal (Refereed)
    Abstract [en]

    Gamma-rays from the alpha- and proton-unstable nuclide Au-171 have been observed for the first time. The gamma-rays were correlated with both a proton- and an alpha-particle decay branch, confirming that the nucleus decays by alpha and proton emission from a single (11/2(-)) state. The measurement confirms the previously determined half-lives for these particle decays but the present values are of higher precision. In addition, a longer half-life than determined in previous work was measured for the proton-unstable tentative ground state. The results are discussed in relation to structures in neighbouring nuclei and compared with a Strutinsky-type TRS calculation.

  • 11.
    Bäck, Torbjörn
    et al.
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Cederkäll, Joakim
    KTH, Superseded Departments, Physics.
    Devlin, M
    Elson, J
    LaFosse, R
    Lerma, F
    Sarantites, G
    Clark, M
    Fallon, P
    Lee, Y
    Macchiavelli, O
    Macleod, W
    Observation of superdeformed states in Mo-881999In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 6, no 4, p. 391-397Article in journal (Refereed)
    Abstract [en]

    High-spin states in Mo-88 were studied using the GAMMASPHERE germanium detector array in conjunction with the MICROBALL CsI(TI) charged-particle detector system. Three gamma-ray cascades with dynamic moments of inertia showing similar characteristics to superdeformed rotational bands observed in the neighbouring A = 80 region have been identified and assigned to the nucleus Mo-88. The quadrupole moment of the strongest band, deduced by the Residual Doppler Shift Method, corresponds to a quadrupole deformation of beta(2) approximate to 0.6. This confirms the superdeformed nature of this band. The experimental data are interpreted in the framework of total routhian surface calculations. All three hands are assigned to two-quasi-particle proton configurations at superdeformed shape.

  • 12.
    Bäck, Torbjörn
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ghazi Moradi, Farnaz
    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.
    Wadsworth, R.
    Transition probabilities near Sn-100 and the stability of the N, Z=50 shell closure2013In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 87, no 3, p. 031306-Article in journal (Refereed)
    Abstract [en]

    Recent B(E2; 0(g.s.)(+) -> 2(1)(+)) measurements in light tin isotopes have revealed surprisingly large values relative to standard shell model predictions, generating an unexpected asymmetry in the B(E2) values with respect to the neutron midshell. This effect has triggered various speculations as to its origin, such as a possible weakening of the N, Z = 50 shell closure. Here we present new shell model calculations to investigate the origin of the observed asymmetric character of the B(E2) values in the tin isotopes. By including the effects of the neutron g(9/2) orbital below the N = 50 shell gap it is shown that Pauli blocking effects may play an important role near the N = 50 shell closure. A new set of single-particle energies and monopole interactions, fitted to the experimental data in the region, together with the isospin-dependent effective charge suggested by Bohr and Mottelson is shown to reproduce the experimental transition rate values in the Sn isotopic chain.

  • 13.
    Bäck, Torbjörn
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Moradi, Farnaz Ghazi
    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.
    Wadsworth, R.
    The B(E2;0(gs)(+) -> 2(+)) systematics of Sn and Te isotopes in light of data in the light Sn region including a recent measurement in Te-108 using the combined recoil-decay-tagging-recoil-distance Doppler technique2012In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T150, p. 014003-Article in journal (Refereed)
    Abstract [en]

    An experimental technique combining the well-established alpha/p-decay-recoil-tagging method with a differential plunger has recently been successful in producing results in the neutron-deficient region near Sn-100. This experimental technique is briefly presented here and the result of a recent measurement for Te-108 is put in the context of the systematics of B(E-2) values for the Te and Sn isotopic chains. New state-of-the-art shell-model calculations are presented for the Sn data, and possible explanations for the unusually large B(E-2) values for the Sn isotopes near the N = 50 shell closure are given.

  • 14.
    Bäck, Torbjörn
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ghazi Moradi, Farnaz
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    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.
    Al-Azri, H.
    Bloor, D.
    Brock, T.
    Wadsworth, R.
    Grahn, T.
    Greenlees, P. T.
    Hauschild, K.
    Herzan, A.
    Jacobsson, U.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Leino, M.
    Lopez-Martens, A.
    Nieminen, P.
    Peura, P.
    Rahkila, P.
    Rinta-Antila, S.
    Ruotsalainen, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Uusitalo, J.
    Go, S.
    Ideguchi, E.
    Cullen, D. M.
    Procter, M. G.
    Braunroth, T.
    Dewald, A.
    Fransen, C.
    Hackstein, M.
    Litzinger, J.
    Rother, W.
    Lifetime measurement of the first excited 2(+) state in (108)Te2011In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 84, no 4, p. 041306-Article in journal (Refereed)
    Abstract [en]

    The lifetime of the first excited 2(+) state in the neutron deficient nuclide (108)Te has been measured for the first time, using a combined recoil decay tagging and recoil distance Doppler shift technique. The deduced reduced transition probability is B(E2;0(g.s.)(+) -> 2(+)) = 0.39(-0.04)(+0.05)e(2)b(2). Compared to previous experimental data on neutron deficient tellurium isotopes, the new data point constitutes a large step (six neutrons) toward the N = 50 shell closure. In contrast to what has earlier been reported for the light tin isotopes, our result for tellurium does not show any enhanced transition probability with respect to the theoretical predictions and the tellurium systematics including the new data is successfully reproduced by state-of-the-art shell model calculations.

  • 15.
    Cederwall, Bo
    et al.
    KTH, Superseded Departments, Physics.
    Bäck, Torbjörn
    KTH, Superseded Departments, Physics.
    Bark, R
    Tormanen, S
    Odegard, S
    King, L
    Simpson, J
    Page, D
    Amzal, N
    Cullen, M
    Greenlees, T
    Keenan, A
    Lemmon, R
    Cocks, C
    Helariutta, K
    Jones, M
    Julin, R
    Juutinen, S
    Kettunen, H
    Kankaanpaa, H
    Kuusiniemi, P
    Leino, M
    Muikku, M
    Rahkila, P
    Savelius, A
    Uusitalo, J
    Magierski, P
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Collective rotational-vibrational transition in the very neutron-deficient nuclei (171,172)-Pt1998In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 443, no 1-4, p. 69-76Article in journal (Refereed)
    Abstract [en]

    Excited states have been identified for the first time in very neutron deficient Pt-171.172 nuclei using the recoil-or-decay tagging technique. The ground-state band in Pt-172 has been established up to I-pi = 8+. A similar level sequence, presumably built on the I-pi = 13/2(+) state, is observed for Pt-171. The data are compared with theoretical calculations based on the mean field approach and the random phase approximation and are put into the context of the systematics of platinum isotopes. (C) 1998 Elsevier Science B.V. All rights reserved.

  • 16. Cederwall, Bo
    et al.
    Bäck, Torbjörn
    Cederkall, J
    Johnson, A
    LaFosse, D R
    Devlin, M
    Elson, J
    Lerma, F
    Sarantites, D G
    Clark, R M
    Lee, I Y
    Macchiavelli, A O
    Macleod, R W
    Bark, R
    Tormanen, S
    Odegard, S
    King, S L
    Simpson, J
    Page, R D
    Amzal, N
    Cullen, D M
    Greenlees, P T
    Keenan, A
    Lemmon, R
    Cocks, J F C
    Helariutta, K
    Jones, P M
    Julin, R
    Juutinen, S
    Hettunen, H
    Kankaanp, H
    Kuusiniemi, P
    Leino, M
    Muikko, M
    Savelius, A
    Uusitalo, J
    Coexistence in proton rich A-90 and A-170 nuclei.1998In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 215, p. U955-U955Article in journal (Refereed)
  • 17.
    Cederwall, Bo
    et al.
    KTH, Superseded Departments, Physics.
    Bäck, Torbjörn
    KTH, Superseded Departments, Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Cederkäll, Joakim
    KTH, Superseded Departments, Physics.
    Devlin, M
    Elson, J
    LaFosse, R
    Lerma, F
    Sarantites, G
    Clark, M
    Fallon, P
    Lee, Y
    Macchiavelli, O
    Macleod, W
    Favoured superdeformed states in 89TC1999In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 6, no 3, p. 251-255Article in journal (Refereed)
    Abstract [en]

    A superdeformed band consisting of a cascade of ten gamma-ray transitions has been identified and assigned to the nucleus Tc-89, close to the proton dripline. The quadrupole moment of the band (Q(t) = 6.7(-2.3)(+3.0) eb, as measured by the Residual Doppler Shift Method) as well as a large dynamic moment of inertia point to a highly elongated shape. With a relative population of approximately 15% of the gamma-ray flux in the Tc-89 exit channel, thp band is among the most intense superdeformed bands observed to date.

  • 18.
    Cederwall, Bo
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ghazi Moradi, Farnaz
    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.
    Blomqvist, Jan-Erik
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Clément, E.
    Grand Accélérateur National d´lons Lourds, Cean Cedex, France.
    de France, G.
    Grand Accélérateur National d´lons Lourds, Cean Cedex, France.
    Wadsworth, R.
    Department of Physics, University of York, UK.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Lagergren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Dijon, A.
    Grand Accélérateur National d´lons Lourds, Cean Cedex, France.
    Jaworski, G.
    Heavy Ion Laboratory, Univeristy of Warsaw, Warsaw, Poland.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Nyakó, B. M.
    Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary.
    Nyberg, J.
    Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.
    Palacz, M.
    Heavy Ion Laboratory, Univeristy of Warsaw, Warsaw, Poland.
    Al-Azri, H.
    Department of Physics, University of York, UK.
    Algora, A.
    IFIC, CSIC University of Valencia, Valencia, Spain.
    de Angelis, G.
    Instituto Nazionael di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, Italy.
    Atac, Ayse
    KTH, School of Engineering Sciences (SCI).
    Bhattacharyya, S.
    Grand Accélérateur National d´lons Lourds, Cean Cedex, France.
    Brock, T.
    Department of Physics, University of York, York, UK.
    Brown, J. R.
    Department of Physics, University of York, York, UK.
    Davies, P.
    Department of Physics, University of York, York, UK.
    Di Nitto, A.
    Dipartimento di Scienze Fisiche, Universitá di Napoli and Instituto Nazionale di Fisica Nucleare, Napoli, Italy.
    Dombrádi, Zs.
    Institute of Nuclear Research of the Hungarian Academy of Science, Debrecen, Hungary.
    Gadea, A.
    IFIC, CSIC, University of Valencia, Valencia, Spain.
    Gál, J.
    Institute of Nuclear Research of the Hungarian Academy of Science, Debrecen, Hungary.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics.
    Johnston-Theasby, F.
    Department of Physics, University of York, York, UK.
    Joshi, P.
    Department of Physics, University of York, York, UK.
    Juhász, K.
    Department of Information Technology, Universty of Debrecen, Debrecen, Hungary.
    Julin, R.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Jungclaus, A.
    Instituto de Estructura de la Materia, Madrid, Spain .
    Kalinka, G.
    Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary.
    Kara, S. O.
    Department of Physics, Ankara University, Tandogan Ankarar, Turkey.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Kownacki, J.
    Heavy Ion Laboratory, Universty of Warsaw, Warsaw, Poland.
    La Rana, G.
    Dipartimento di Scienze Fisiche, Universitá di Napoli and Instituto Nazionale di Fisica Nucleare, Napoli, Italy.
    Lenzi, S. M.
    Dipartimento di Fisica dell'Universitá di Padova and Instituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova, Italy.
    Molnár, J.
    Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary.
    Moro, R.
    Dipartimento di Scienze Fisiche, Universitá di Napoli and Instituto Nazionale di Fisica Nucleare, Napoli, Italy.
    Napoli, D. R.
    Instituto Nazionale di Fisica Nucleare, Laboratori Natzionali di Legnaro, Legnaro, Italy.
    Nara Singh, B. S.
    Department of Physics, University of York, York, UK.
    Persson, Andreas
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Recchia, F.
    Dipartimento di Fisica dell'Universitá di Padova and Instituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova, Italy.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics.
    Scheurer, J. -N
    Université Bordeaux, Centre d'Etudes Nucléaires de Bordeaux Gradignan, Gradignan, France.
    Sletten, G.
    The Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.
    Sohler, D.
    Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary.
    Söderström, P. -A
    Department of Physics and Astromony, Uppsala University, Uppsala, Sweden.
    Taylor, M. J.
    Department of Physics, University of York, York, UK.
    Timár, J.
    Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary.
    Valiente-Dobón, J. J.
    instituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, Italy.
    Vardaci, E.
    Dipartimento di Scienze Fisiche, Universitá di Napoli and Instituto Nazionale di Fisica Nucleare, Napoli, Italy.
    Williams, S.
    TRIUMF, Vancouver, British Columbia, Canada.
    Evidence for a spin-aligned neutron-proton paired phase from the level structure of 92Pd2011In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 469, no 7328, p. 68-71Article in journal (Refereed)
    Abstract [en]

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

  • 19. Davies, P. J.
    et al.
    Grawe, H.
    Moschner, K.
    Blazhev, A.
    Wadsworth, R.
    Boutachkov, P.
    Ameil, F.
    Yagi, A.
    Baba, H.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Dewald, M.
    Doornenbal, P.
    Faestermann, T.
    Gengelbach, A.
    Gerl, J.
    Gernhaeeuserk, R.
    Go, S.
    Gorska, M.
    Gregor, E.
    Isobe, T.
    Jenkins, D. G.
    Hotaka, H.
    Jolie, J.
    Kojouharov, I.
    Kurz, N.
    Lewitowicz, M.
    Lorusso, G.
    Maier, L.
    Merchan, E.
    Naqvi, F.
    Nishibata, H.
    Nishimura, D.
    Nishimura, S.
    Nowacki, F.
    Pietralla, N.
    Schaffne, H.
    Soderstrom, P-A
    Jung, H. S.
    Steiger, K.
    Sumikama, T.
    Taprogge, J.
    Thoele, P.
    Warr, N.
    Watanabe, H.
    Werner, V.
    Xu, Z. Y.
    Yoshinaga, K.
    Zhu, Y.
    The role of core excitations in the structure and decay of the 16(+) spin-gap isomer in Cd-962017In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 767, p. 474-479Article in journal (Refereed)
    Abstract [en]

    The first evidence for beta-delayed proton emission from the 16(+) spin gap isomer in Cd-96 is presented. The data were obtained from the Rare Isotope Beam Factory, at the RIKEN Nishina Center, using the BigRIPS spectrometer and the EURICA decay station. beta p branching ratios for the ground state and 16(+) isomer have been extracted along with more precise lifetimes for these states and the lifetime for the ground state decay of Cd-95. Large scale shell model (LSSM) calculations have been performed and WKB estimates made for l = 0, 2, 4 proton emission from three resonance-like states in Ag-96, that are populated by the beta decay of the isomer, and the results compared to the new data. The calculations suggest that l = 2 proton emission from the resonance states, which reside similar to 5 MeV above the proton separation energy, dominates the proton decay. The results highlight the importance of core-excited wavefunction components for the 16(+) state.

  • 20. Doncel, Maria
    et al.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Cullen, D. M.
    Hodge, D.
    Qi, Chong
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Taylor, M. J.
    Procter, M.
    Auranen, K.
    Grahn, T.
    Greenlees, P. T.
    Jakobsson, U.
    Julin, R.
    Juutinen, S.
    Herzan, A.
    Konki, J.
    Leino, M.
    Pakarinen, J.
    Partanen, J.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Stolze, S.
    Uusitalo, J.
    Lifetime measurement of the first excited 2(+) state in Te-1122015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 91, no 6, article id 061304Article in journal (Refereed)
    Abstract [en]

    The lifetime of the 2(+) --> 0(g.s.)(+) transition in the neutron-deficicient nucleus Te-112 has been measured for the first time using the DPUNS plunger and the recoil distance Doppler shift technique. The deduced value for the reduced transition probability is B(E2 :0(g.s.)(+) --> 2(+)) = 0.46 +/- 0.04 e(2)b(2), indicating that there is no unexpected enhancement of the B(E2 :0(g.s.)(+) --> 2(+)) values in Te isotopes below the midshell. The result is compared to and discussed in the framework of large-scale shell-model calculations.

  • 21.
    Doncel, Maria
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Qi, C.
    Cullen, D. M.
    Hodge, D.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Taylor, M. J.
    Procter, M.
    Giles, M.
    Auranen, K.
    Grahn, T.
    Greenlees, P. T.
    Jakobsson, U.
    Julin, R.
    Juutinen, S.
    Herzáň, A.
    Konki, J.
    Pakarinen, J.
    Partanen, J.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Sarén, J.
    Scholey, C.
    Sorri, J.
    Stolze, S.
    Uusitalo, J.
    Spin-dependent evolution of collectivity in Te 1122017In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 96, no 5, article id 051304Article in journal (Refereed)
    Abstract [en]

    The evolution of collectivity with spin along the yrast line in the neutron-deficient nucleus Te112 has been studied by measuring the reduced transition probability of excited states in the yrast band. In particular, the lifetimes of the 4+ and 6+ excited states have been determined by using the recoil distance Doppler-shift method. The results are discussed using both large-scale shell-model and total Routhian surface calculations.

  • 22. Erni, L.
    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,
    Technical design report for the PANDA (AntiProton Annihilations at Darmstadt) Straw Tube Tracker2013In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 49, no 2Article in journal (Refereed)
    Abstract [en]

    This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the PANDA target spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner tracking and is followed in beam direction by a set of GEM stations. The tasks of the STT are the measurement of the particle momentum from the reconstructed trajectory and the measurement of the specific energy loss for a particle identification. Dedicated simulations with full analysis studies of certain proton-antiproton reactions, identified as being benchmark tests for the whole PANDA scientific program, have been performed to test the STT layout and performance. The results are presented, and the time lines to construct the STT are described.

  • 23.
    Ertoprak, Aysegul
    et al.
    KTH, School of Engineering Sciences (SCI), Physics. Istanbul University Vezneciler/Fatih, Istanbul, Turkey.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jakobsson, U.
    KTH, School of Engineering Sciences (SCI), Physics.
    Nyako, B. M.
    Nyberg, J.
    Davies, P.
    Doncel, Maria
    KTH, School of Engineering Sciences (SCI), Physics.
    De France, G.
    Kuti, I.
    Napoli, D. R.
    Wadsworth, R.
    Ghugre, S. S.
    Raut, R.
    Akkus, B.
    Al-Azri, H.
    Algora, A.
    de Angelis, G.
    Atac, A.
    KTH, School of Engineering Sciences (SCI), Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Boso, A.
    Clement, E.
    Debenham, D. M.
    Dombradi, Zs.
    Erturk, S.
    Gadea, A.
    Ghazi Moradi, Farnaz
    KTH, School of Engineering Sciences (SCI), Physics.
    Gottardo, A.
    Huyuk, T.
    Ideguchi, E.
    Jaworski, G.
    Li, H.
    KTH, School of Engineering Sciences (SCI), Physics.
    Michelagnoli, C.
    Modamio, V.
    Palacz, M.
    Petrache, C. M.
    Recchia, F.
    Sandzelius, M.
    Siciliano, M.
    Timar, J.
    Valiente-Dobon, J. J.
    Xiao, Z. G.
    LIFETIME MEASUREMENTS WITH THE DOPPLER SHIFT ATTENUATION METHOD USING A THICK HOMOGENEOUS PRODUCTION TARGET - VERIFICATION OF THE METHOD2017In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 48, no 3, p. 325-329Article in journal (Refereed)
    Abstract [en]

    Doppler Shift Attenuation Method (DSAM) analysis of excited-state lifetimes normally employs thin production targets mounted on a thick stopper foil ("backing") serving to slow down and stop the recoiling nuclei of interest in a well-defined manner. Use of a thick, homogeneous production target leads to a more complex analysis as it results in a substantial decrease in the energy of the incident projectile which traverses the target with an associated change in the production cross section of the residues as a function of penetration depth. Here, a DSAM lifetime analysis using a thick homogeneous target has been verified using the Doppler broadened lineshapes of gamma rays following the decay of highly excited states in the semi-magic (N = 50) nucleus Ru-94. Lifetimes of excited states in the Ru-94 nucleus have been obtained using a modified version of the LINESHAPE package from the Doppler broadened lineshapes resulting from the emission of the gamma rays, while the residual nuclei were slowing down in the thick (6 mg/cm(2)) metallic Ni-58 target. The results have been validated by comparison with a previous measurement using a different (RDDS) technique.

  • 24.
    Ghazi Moradi, Farnaz
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Atac, Ayse
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Eeckhaudt, S.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Grahn, T.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Greenlees, P. T.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Jones, P. M.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Julin, R.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Juutinen, S.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Ketelhut, S.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Leino, M.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Nyman, M.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Rahkila, P.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Sarén, J.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Scholey, C.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Sorri, J.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Uusitalo, J.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Ganioglu, E.
    Science Faculty, Physics Department, Istanbul University, Istanbul, Turkey.
    Thomson, J.
    Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK.
    Joss, D. T.
    Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK.
    Page, R. D.
    Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK.
    Ertürk, S.
    CCLRC Daresbury Laboratory, Daresbury, Warrington, UK.
    Simpson, J.
    CCLRC Daresbury Laboratory, Daresbury, Warrington, UK.
    Gomez Hornillos, M. B.
    Seccio d'Enginyeria Nuclear, Universitat Politecnica de Catalunya, Barcelona, Spain.
    Bianco, L.
    Department of Physics, University of Guelph, Ontario, Canada.
    High-spin study of 162Ta2011In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 84, no 6, p. 064312-Article in journal (Refereed)
    Abstract [en]

    Excited states in the odd-odd neutron deficient nucleus (162)Ta (Z = 73, N = 89) have been studied for the first time. The gamma spectroscopy analysis using gamma - gamma - gamma coincidences revealed a strongly coupled rotational structure that was established up to large angular momentum states. The rotational band was assigned to the configuration pi h(11/2)[514]9/2 circle times nu i(13/2)[660]1/2 based on its rotational and electromagnetic properties. The data are interpreted within the framework of total Routhian surface calculations, which suggests an axially symmetric shape with a gamma-softminimum at beta(2) approximate to 0.16 and gamma approximate to 6 degrees. The crossing of the signature partners observed in heavier (N >= 91) odd-odd nuclides in this mass region is found to be absent at N = 89. This might be correlated with a change in S-band structure above the paired band crossing at these neutron numbers.

  • 25.
    Ghazi Moradi, Farnaz
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ataç, Ayşe
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Doncel, Maria
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    de France, G.
    Clement, E.
    Nyberg, J.
    Gengelbach, A.
    Nyako, B. M.
    Gal, J.
    Kalinka, G.
    Molnar, J.
    Timar, J.
    Sohler, D.
    Dombradi, Zs.
    Kuti, I.
    Juhasz, K.
    Napoli, D. R.
    Gottardo, A.
    Modamio, V.
    Wadsworth, R.
    Henry, T. W.
    Nichols, A. J.
    Al-Azri, H.
    Palacz, M.
    Ideguchi, E.
    Aktas, O.
    Di Nitto, A.
    Dijon, A.
    Hueyuek, T.
    Jaworski, G.
    John, P. R.
    Yilmaz, B.
    Spectroscopy of the neutron-deficient N=50 nucleus Rh-952014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 89, no 4, p. 044310-Article in journal (Refereed)
    Abstract [en]

    The neutron-deficient semimagic (neutron number N = 50) Rh-95 nucleus has been produced at high spins using the projectile-target system Ca-40 + Ni-58 at 125 MeV beam energy. The gamma-decays of levels populated by the 3p fusion evaporation reaction channel were studied using gamma-gamma coincidences, and 20 new gamma-ray transitions involving 15 new positive-and negative-parity states were observed. Spin and parity for many of the excited states were firmly deduced for the first time using the combined directional angular correlation and direction-polarization techniques. The observed structures are discussed within the framework of large-scale shell model calculations. E1 transition strengths were deduced and used together with the results of the shell model calculations to study the contribution of different particle-hole configurations, in particular for analyzing contributions from core-excited configurations.

  • 26.
    Ghazi Moradi, Farnaz
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ataç, Ayşe
    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.
    Doncel, Maria
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    et al.,
    Character of particle-hole excitations in Ru-94 deduced from gamma-ray angular correlation and linear polarization measurements2014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 89, no 1, p. 0143011-0143019Article in journal (Refereed)
    Abstract [en]

    Linear polarization and angular correlations of γ-rays depopulating excited states in the neutron-deficient nucleus 9444Ru50 have been measured, enabling firm spin-parity assignments for several excited states in this nucleus. The deduced multipolarities of strong transitions in the yrast structure were found to be mostly of stretched M1, E1, and E2 types and, in most cases, in agreement with previous tentative assignments. The deduced multipolarity of the 1869 keV and the connecting 257 and 1641 keV transitions indicates that the state at 6358 keV excitation energy has spin parity 12−1 rather than 12+3 as proposed in previous works. The presence of a 12−1 state is interpreted within the framework of large-scale shell-model calculations as a pure proton-hole state dominated by the π(p−11/2⊗g−59/2) and π(p−13/2⊗g−59/2) configurations. A new positive-parity state is observed at 6103 keV and is tentatively assigned as 12+2. The 14−1 state proposed earlier is reassigned as 13−4 and is interpreted as being dominated by neutron particle-hole core excitations. The strengths of several E1 transitions have been measured and are found to provide a signature of core-excited configurations.

  • 27.
    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.

  • 28.
    Hadinia, Baharak
    et al.
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Lagergren, Karin
    KTH, Superseded Departments, Physics.
    Blomqvist, Jan
    KTH, Superseded Departments, Physics.
    Bäck, Torbjörn
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Liotta, Roberto
    KTH, Superseded Departments, Physics.
    et al.,
    First identification of gamma-ray transitions in 107Te2004In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 70, no 6, p. 064314-1-064314-4Article in journal (Refereed)
    Abstract [en]

    Gamma-ray transitions in Te-107 have been identified for the first time. The experiment, which utilized the recoil decay tagging technique, was performed at the accelerator laboratory of the University of Jyvaskyla, Finland. Prompt gamma rays produced in Ni-58(Cr-52,3n)Te-107(*) reactions were detected by the JUROGAM gamma-ray spectrometer. The gamma rays belonging to Te-107 were selected based on the recoil identification provided by the RITU gas-filled recoil separator and the GREAT focal plane spectrometer. A first excited state at 90 keV, tentatively of g(7/2) character, is proposed.

  • 29.
    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.

  • 30. Ideguchi, E.
    et al.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Milechina, Larissa
    Gono, Y.
    Yang, Y. F.
    Aoi, N.
    Teranishi, T.
    Bucurescu, D.
    Kishida, T.
    Position sensitivity of a segmented planar Ge detector2003In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 496, no 03-feb, p. 373-384Article in journal (Refereed)
    Abstract [en]

    A method to extract depth of interaction information for gamma-rays in a segmented planar Ge detector is presented. The method is demonstrated on signals from a segmented detector which were stored by a digital oscilloscope event by event and analysed off-line. Event samples were acquired for different interaction points in the detector. A Compton scatter coincidence detection technique ensured that the event samples were highly enriched in single-interaction events. By analysing pulse shapes and the relative timing between anode pulses and the pulses from the irradiated cathode segment, a position sensitivity of 1-2 mm in the depth direction was deduced. A similar transverse position sensitivity was inferred by studying image charge pulses on neighbouring segments.

  • 31. 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.

  • 32.
    Ideguchi, Eiji
    et al.
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Bäck, Torbjörn
    KTH, Superseded Departments, Physics.
    Lagergren, Karin
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Cederkäll, Joakim
    KTH, Superseded Departments, Physics.
    Devlin, M
    Elson, J
    LaFosse, R
    Lerma, F
    Sarantites, G
    Tomov, V
    Hausmann, M
    Jungclaus, A
    Napoli, R
    Carpenter, P
    Janssens, F
    Kondev, G
    Lauritsen, T
    Lister, J
    Seweryniak, D
    Wiedenhoever, I
    Clark, M
    Fallon, P
    Lee, Y
    Macchiavelli, O
    Macleod, W
    Superdeformation in 91Tc2000In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 492, no 3-4, p. 245-253Article in journal (Refereed)
    Abstract [en]

    A high-spin rotational band with 11 gamma -ray transitions has barn observed in Tc-91. The dynamical moment of inertia as well as the transition quadrupole moment of 8.1(-1.4)(+1.9) eb measured for this band show the characteristics of a superdeformed band. However, the shape is more elongated than in the neighbouring A = 80-90 superdeformed nuclei. Theoretical interpretations of the band within the cranked Strutinsky approach based on two different Woods-Saxon potential parameterisations are presented. Even though an unambiguous configuration assignment proved difficult, both calculations indicate a larger deformation and at least three additional high-N intruder orbitals occupied compared to the lighter SD nuclei. (C) 2000 Elsevier Science B.V. All rights reserved.

  • 33. Jonsson, K
    et al.
    Cederwall, Bo
    Johnson, A
    Wyss, R
    Bäck, Torbjörn
    Cederkall, J
    Devlin, M
    Elson, J
    LaFosse, D R
    Lerma, F
    Sarantites, D G
    Clark, R M
    Lee, I Y
    Macchiavelli, A O
    Macleod, R W
    Collective excitations and band termination in Nb-851999In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 645, no 1, p. 47-60Article in journal (Refereed)
    Abstract [en]

    High-spin states in Nb-85 were studied using the GAMMASPHERE Ge detector array and the MICROBALL charged-particle detector system. Three gamma-ray cascades with collective rotational characteristics were observed. One of the bands exhibits a forking at the top, most likely reflecting the termination of one branch into a favoured non-collective, near spherical state. The data are interpreted in terms of cranked Strutinsky-type calculations.

  • 34. 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.

  • 35. Joss, D. T.
    et al.
    King, S. L.
    Page, R. D.
    Simpson, J.
    Keenan, A.
    Amzal, N.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), 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.
    Kankaanpaa, H.
    Kettunen, H.
    Kuusiniemi, P.
    Leino, M.
    Muikku, M.
    Savelius, A.
    Uusitalo, J.
    Williams, S. J.
    Identification of excited states in Os-167 and Os-168: shape coexistence at extreme neutron deficiency2001In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 689, no 04-mar, p. 631-654Article in journal (Refereed)
    Abstract [en]

    Excited states in the very neutron-deficient isotopes Os-167 and Os-168 have been observed using the reaction Sn-112(Ni-58, 2pxn). The JUROSPHERE gamma -ray spectrometer array was used in conjunction with the RITU gas-filled recoil separator to collect prompt gamma radiation in coincidence with recoils implanted in a silicon strip detector located at the focal plane of RITU. Using a selective recoil decay tagging technique it has been possible to unambiguously assign gamma -ray transitions to Os-167 and Os-168 through the characteristic a radioactivity of these nuclides. The high-spin structure of the bands is discussed in terms of quasiparticle configurations within the framework of the cranked shell model. The role of shape coexistence in Os-168 is examined with phenomenological three-band mixing calculations.

  • 36. 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.

  • 37. 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.

  • 38. King, S L
    et al.
    Simpson, J
    Page, R D
    Amzal, N
    Bäck, Torbjörn
    Cederwall, Bo
    Cocks, J F C
    Cullen, D M
    Greenlees, P T
    Harder, M K
    Helariutta, K
    Jones, P
    Julin, R
    Juutinen, S
    Kankaanpaa, H
    Keenan, A
    Kettunen, H
    Kuusiniemi, P
    Leino, M
    Lemmon, R
    Muikku, M
    Savelius, A
    Uusitalo, J
    Van Isacker, P
    First observation of excited states in the neutron deficient nuclei (PT)-P-168 and Pt-1701998In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 443, no 1-4, p. 82-88Article in journal (Refereed)
    Abstract [en]

    Excited states have been observed for the first time in (XPt)-X-168 and Pt-170 using the alpha-decay recoil-tagging technique. The trend of decreasing deformation moving away from the N = 104 mid-shell continues far Pt-170 but the structure of Pt-168 is significantly different. The low spin level energy systematics in Pt168-184 are presented and discussed within the framework of the interacting boson model. (C) 1998 Elsevier Science B.V. All rights reserved.

  • 39. Kishida, T.
    et al.
    Watanabe, H.
    Ideguchi, E.
    Kubo, T.
    Yang, Y. F.
    Ishihara, M.
    Yamamoto, S.
    Gono, Y.
    Morikawa, T.
    Tsutsumi, T.
    Fukuchi, T.
    Motomura, S.
    Tsuchida, H.
    Kashiyama, O.
    Saitoh, K.
    Shibata, M.
    Odahara, A.
    Zhang, Y. H.
    Zhou, X. H.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Bucurescu, D.
    High-spin isomeric beam line2002In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 484, no 03-jan, p. 45-55Article in journal (Refereed)
    Abstract [en]

    A high-spin isomeric beam line has been constructed at RIKEN based on the inverse kinematics of fusion-evaporation reactions. The beam line provides high-spin isomers as secondary beams, whose intensity is more than 10(5) sec(-1). The characteristics and the present status of the beam line are described.

  • 40.
    Lagergren, K
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Ideguchi, E.
    KTH, School of Engineering Sciences (SCI), Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Atac, Ayse
    Axelsson, A.
    Azaiez, F.
    Bracco, A.
    Cederkäll, Joakim
    KTH, School of Engineering Sciences (SCI), Physics.
    Dombradi, Z.
    Fahlander, C.
    Gadea, A.
    Million, B.
    Petrache, C. M.
    Rossi-Alvarez, C.
    Sampson, J. A.
    Sohler, D.
    KTH, School of Engineering Sciences (SCI), Physics.
    Weiszflog, M.
    Coexistence of superdeformed shapes in Er-1542001In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 8702, no 2Article in journal (Refereed)
    Abstract [en]

    A new superdeformed rotational band has been observed in Er-154 using the Euroball Ge detector array. The new band and the one previously observed can be understood as based on coexisting superdeformed structures at prolate and triaxial shapes, respectively. The observation resolves long-standing difficulties in the theoretical interpretation of superdeformed states in Er-154.

  • 41.
    Lagergren, K
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Blomqvist, J.
    Sohler, D.
    de Angelis, G.
    Bednarczyk, P.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Claesson, T.
    KTH, School of Engineering Sciences (SCI), Physics.
    Dorvaux, O.
    Farnea, E.
    Gadea, A.
    Gorska, M.
    Milechina, Larissa
    KTH, School of Engineering Sciences (SCI), Physics.
    Norlin, L. O.
    KTH, School of Engineering Sciences (SCI), Physics.
    Odahara, A.
    Palacz, M.
    Stefanescu, I.
    Thelen, O.
    Vivien, J. P.
    Evidence for excited states in Ag-952002In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 14, no 4, p. 393-396Article in journal (Refereed)
    Abstract [en]

    The first evidence for excited states in Ag-95 is presented. Ag-95 is the heaviest T-z = 1/2 nucleus for which gamma-rays have been identified. The reaction Ca-40(Ni-58, 1p2n)Ag-95 was used in the experiment, which resulted in the assignment of three gamma-rays to Ag-95. A detector system consisting of the detector arrays Euroball, Neutron Wall and Euclides was used to detect gamma-rays, neutrons and charged particles, respectively.

  • 42.
    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.

  • 43.
    Li, Hongjie
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. Tsinghua Univ, Dept Phys, Beijing 100084, Peoples R China.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Doncel, Maria
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jakobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. Univ Jyvaskyla, Dept Phys, POB 35, FI-40014 Jyvaskyla, Finland.
    Xiao, Z. G.
    et al.,
    Lifetime measurements in Re-166: Collective versus magnetic rotation2016In: PHYSICAL REVIEW C, ISSN 2469-9985, Vol. 93, no 3, article id 034309Article in journal (Refereed)
    Abstract [en]

    Lifetimes of excited states in the neutron-deficient odd-odd nucleus Re-166 have been measured for the first time using the recoil distance Doppler-shift method. The measured lifetime for the (8(-)) state; tau = 480 (80) ps, enabled an assessment of the multipolarities of the gamma rays depopulating this state. Information on electromagnetic transition strengths were deduced for the gamma-ray transitions from the (9(-)), (10(-)), and (11(-)) states, and in the case of the (10(-)) and (11(-)) states limits on the B (M1) and B(E2) strengths were estimated. The results are compared with total Routhian surface predictions and semiclassical calculations. Tilted-axis cranking calculations based on a relativistic mean-field approach (TAC-RMF) have also been performed in order to test the possibility of magnetic rotation in the 166Re nucleus. While the TAC-RMF calculations predict a quadrupole-deformed nuclear shape with similar beta(2) deformation as obtained by using the TRS model, it was found that the experimental electromagnetic transition rates are in better agreement with a collective -rotational description.

  • 44.
    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.

  • 45. Mach, H.
    et al.
    Walker, P. M.
    Julin, R.
    Leino, M.
    Juutinen, S.
    Stanoiu, M.
    Podolyak, Z.
    Wood, R.
    Bruce, A. M.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Cameron, J. A.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ekman, J.
    Fogelberg, B.
    Greenless, P. T.
    Hellström, M.
    Jones, P.
    Klamra, Wlodzimierz
    Lagergren, K.
    Leppanen, A. P.
    Nieminen, P.
    Orlandi, R.
    Pakarinen, J.
    Rahkila, P.
    Rudolph, D.
    Simpson, G.
    Uusitalo, J.
    Wheldon, C.
    Application of ultra-fast timing techniques to the study of exotic and weakly produced nuclei2005In: Journal of Physics G: Nuclear and Particle Physics, ISSN 0954-3899, E-ISSN 1361-6471, Vol. 31, no 10, p. S1421-S1426Article in journal (Refereed)
    Abstract [en]

    Ultra-fast time-delayed techniques have been recently applied in a number of studies where exotic nuclei were identified using advanced selection techniques. These include large Compton-suppressed Ge arrays, in-flight separators or recoil separators. Some of the new results are discussed in this presentation. Besides the results for Mg-32 and Pd-96, they include the first determination of the half-life of the 8(+) state in Ge-80, T-1/2 = 2.95(6) ns, and significantly more precise results for Mn-51 (3680 keV level) and V-48 (421 keV level), T-1/2 = 1760(40) ps and T-1/2.

  • 46. Moschner, K.
    et al.
    Blazhev, A.
    Warr, N.
    Boutachkov, P.
    Davies, P.
    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.
    Gernhaeuser, R.
    Go, S.
    Gorska, 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.
    Merchan, E.
    Naqvi, F.
    Nishibata, H.
    Nishimura, D.
    Nishimura, S.
    Pietralla, N.
    Schaffner, H.
    Soederstroem, P. -A
    Steiger, K.
    Sumikama, T.
    Taprogge, J.
    Thoele, P.
    Watanabe, H.
    Werner, V.
    Xu, Z. Y.
    Yagi, A.
    Yoshinaga, K.
    Zhu, Y.
    Study of ground and excited state decays in N approximate to Z Ag nuclei2015In: CGS15 - CAPTURE GAMMA-RAY SPECTROSCOPY AND RELATED TOPICS, 2015, Vol. 93, article id UNSP 01024Conference paper (Refereed)
    Abstract [en]

    A decay spectroscopy experiment was performed within the EURICA campaign at RIKEN in 2012. It aimed at the isomer and particle spectroscopy of excited states and ground states in the mass region below the doubly magic Sn-100. The N = Z nuclei In-98, Cd-96 and Ag-94 were of particular interest for the present study. Preliminary results on the neutron deficient nuclei Ag-93 and Ag-94 are presented. In Ag-94 a more precise value for the half-life of the ground state's superallowed Fermi transition was deduced. In addition the energy spectra of the mentioned decay could be reproduced through precise Geant4 simulations of the used active stopper SIMBA. This will enable us to extract Q(beta) values from the measured data. The decay of Ag-93 is discussed based on the observed implantation-decay correlation events.

  • 47. 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.

  • 48. 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.

  • 49. 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.

  • 50. Procter, M. G.
    et al.
    Cullen, D. M.
    Ruotsalainen, P.
    Scholey, C.
    Angus, L.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Dewald, A.
    Fransen, C.
    Grahn, T.
    Greenlees, P. T.
    Hackstein, M.
    Jakobsson, U.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Leino, M.
    Lumley, N. M.
    Mason, P. J. R.
    Nieminen, P.
    Nyman, M.
    Pakarinen, J.
    Pissulla, T.
    Peura, P.
    Rahkila, P.
    Revill, J.
    Rigby, S. V.
    Rother, W.
    Sandzelius, M.
    Sarén, J.
    Sorri, J.
    Taylor, M. J.
    Uusitalo, J.
    Wady, P.
    Qi, C.
    Xu, F. R.
    Lifetime measurement in the proton-unbound nucleus 109I2011In: AIP Conf. Proc., 2011, p. 105-110Conference paper (Refereed)
    Abstract [en]

    The Recoil-Distance Doppler-shift method has been combined with Recoil-Decay Tagging for the first time to measure a lifetime in the proton-unbound nucleus 109I. The lifetime value was determined using the Differential Decay-Curve method in singles mode. The result has been compared to theoretical shell-model calculations in order to better understand the nature of unbound valence nucleons at the proton drip line.

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