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  • 1. Boso, A.
    et al.
    Lenzi, S. M.
    Recchia, F.
    Bonnard, J.
    Aydin, S.
    Bentley, M. A.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Clement, E.
    De France, G.
    Di Nitto, A.
    Dijon, A.
    Doncel, Maria
    KTH, School of Engineering Sciences (SCI), Physics.
    Ghazi Moradi, Farnaz
    KTH, School of Engineering Sciences (SCI), Physics.
    Gottardo, A.
    Henry, T.
    Huyuk, T.
    Jaworski, G.
    John, P. R.
    Juhasz, K.
    Kuti, I.
    Melon, B.
    Mengoni, D.
    Michelagnoli, C.
    Modamio, V.
    Napoli, D. R.
    Nyako, B. M.
    Nyberg, J.
    Palacz, M.
    Valiente-Dobon, J. J.
    ISOSPIN SYMMETRY BREAKING IN MIRROR NUCLEI Mg-23-Na-232017In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 48, no 3, p. 313-318Article in journal (Refereed)
    Abstract [en]

    Mirror energy differences (MED) are a direct consequence of isospin symmetry breaking. Moreover, the study of MED has proved to give valuable information of several nuclear structure properties. We present the results of an experiment performed in GANIL to study the MED in mirror nuclei Mg-23-Na-23 up to high spin. The experimental values are compared with state-of-the-art shell model calculations. This permits to enlighten several nuclear structure properties, such as the way in which the nucleons alignment proceeds, the radius variation with J, the role of the spin-orbit interaction and the importance of isospin symmetry breaking terms of nuclear origin.

  • 2. Carroll, R. J.
    et al.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwal, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Doncel, Maria
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. Department of Physics, University of Guelph, Guelph, ON, Canada.
    Jacobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. University of Jyväskylä, Department of Physics, Jyväskylä, Finland.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Taylor, M. J.
    Thornthwaite, A.
    et al.,
    Excited states in the proton-unbound nuclide Ta-1582016In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 93, no 3, article id 034307Article in journal (Refereed)
    Abstract [en]

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

  • 3. 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.

  • 4.
    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.

  • 5.
    Doncel, Maria
    et al.
    KTH. University of Liverpool, United Kingdom.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Gadea, A.
    Gerl, J.
    Kojouharov, I.
    Martin, S.
    Palit, R.
    Quintana, B.
    Performance and imaging capabilities of the DEGAS high-resolution gamma-ray detector array for the DESPEC experiment at FAIR2017In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 873, p. 36-38Article in journal (Refereed)
    Abstract [en]

    Monte Carlo simulations of one of the possible configurations of the imaging phase for the DEGAS spectrometer situated at the DESPEC/NUSTAR experiment have been performed. The geometry consists of the coupling of the high-resolution gamma spectroscopy array, AGATA, with a high-resolution segmented planar detector utilized as an implantation detector in a compact configuration. The sensitivity and performance of the array in terms of efficiency and imaging capability is deduced.

  • 6.
    Doncel, Maria
    et al.
    KTH, School of Engineering Sciences (SCI), Physics. Universidad de Salamanca, Spain.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Martin, S.
    Quintana, B.
    Gadea, A.
    Farnea, E.
    Algora, A.
    Conceptual design of a high resolution Ge array with tracking and imaging capabilities for the DESPEC (FAIR) experiment2015In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 10, article id P06010Article in journal (Refereed)
    Abstract [en]

    We present results of Monte Carlo simulations for the conceptual design of the high-resolution DESPEC Germanium Array Spectrometer (DEGAS) proposed for the Facility for Ion and Antiproton Research (FAIR) under construction at Darmstadt, Germany. The project is carried out in three phases, although only results for the two first phases will be addressed in this work. The first phase will consist of a re-arrangement of the EUROBALL cluster detectors previously used in the RISING campaign at GSI. The second phase is based on coupling AGATA-type triple-cluster detectors with EUROBALL cluster detectors in a compact geometry around the active ion implantation target of DESPEC.

  • 7.
    Doncel, Maria
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics.
    Li, Hongjie J.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jakobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics.
    Auranen, K.
    Boenig, S.
    Drummond, M. C.
    Grahn, T.
    Greenlees, P. T.
    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.
    Lifetime measurements of excited states in W-162 and W-164 and the evolution of collectivity in rare-earth nuclei2017In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 95, no 4, article id 044321Article in journal (Refereed)
    Abstract [en]

    Lifetimes of the first excited 2(+) states in the extremely neutron- deficient W-162 and W-164 nuclei have been measured using the recoil distance Doppler shift technique. Experimental B(E2) data for the isotopic chains of hafnium, tungsten, and osmium, from the midshell region near the beta-stability line towards the N = 82 closed shell and the most neutron-deficient nuclides, are compared with predictions of nuclear deformations and 2(1)(+) -> 0(g.s)(.+) reduced transition strengths from different classes of state-of-the-art theoretical model calculations. The results reveal striking differences and deficiencies in the predictive power of current nuclear structure models.

  • 8.
    Doncel, Maria
    et al.
    KTH, School of Engineering Sciences (SCI), Physics. Universidad de Salamanca, Spain; University of Liverpool, United Kingdom.
    Gadea, A.
    Valiente-Dobon, J. J.
    Quintana, B.
    Modamio, V.
    Mengoni, D.
    Moller, O.
    Dewald, A.
    Pietralla, N.
    Determination of lifetimes of nuclear excited states using the Recoil Distance Doppler Shift Method in combination with magnetic spectrometers2017In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 53, no 10, article id 211Article in journal (Refereed)
    Abstract [en]

    The current work presents the determination of lifetimes of nuclear excited states using the Recoil Distance Doppler Shift Method, in combination with spectrometers for ion identification, normalizing the intensity of the peaks by the ions detected in the spectrometer as a valid technique that produces results comparable to the ones obtained by the conventional shifted-to-unsifted peak ratio method. The technique has been validated using data measured with the gamma-ray array AGATA, the PRISMA spectrometer and the Cologne plunger setup. In this paper a test performed with the AGATA-PRISMA setup at LNL and the advantages of this new approach with respect to the conventional Recoil Distance Doppler Shift Method are discussed.

  • 9.
    Doncel, Maria
    et al.
    University of Salamanca, Spain .
    Sahin, E.
    Gadea, A.
    de Angelis, G.
    Quintana, B.
    Valiente-Dobon, J. J.
    Modamio, V.
    Albers, M.
    Bazzacco, D.
    Clement, E.
    Corradi, L.
    Dewald, A.
    Duchene, G.
    Erduran, M. N.
    Farnea, E.
    Fioretto, E.
    Fransen, C.
    Gernhaeuser, R.
    Goergen, A.
    Gottardo, A.
    Hackstein, M.
    Hernandez-Prieto, A.
    Hueyuek, T.
    Klupp, S.
    Korten, W.
    Kusoglu, A.
    Lenzi, S.
    Louchart, C.
    Lunardi, S.
    Menegazzo, R.
    Mengoni, D.
    Michelagnoli, C.
    Mijatovic, T.
    Montagnoli, G.
    Montanari, D.
    Moeller, O.
    Napoli, D. R.
    Obertelli, A.
    Orlandi, R.
    Pollarolo, G.
    Recchia, F.
    Rother, W.
    Salsac, M. -D
    Scarlassara, F.
    Schlarb, M.
    Stefanini, A.
    Sulignano, B.
    Szilner, S.
    Ur, C. A.
    Lifetime Measurements in Neutron-rich Cu Isotopes2013In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 44, no 3, p. 505-510Article in journal (Refereed)
    Abstract [en]

    The nuclear structure of neutron-rich nuclei close to the double-magic nucleus Ni-78 has been investigated by measuring the lifetime of excited states. In this contribution, it will be presented the lifetime of the J(pi) = 7/2(-) excited state at 981 keV of the Cu-71 isotope, measured using the AGATA Demonstrator coupled to the PRISMA spectrometer and the Koln plunger setup. This is the first time this combined setup has been used for a lifetime measurement.

  • 10.
    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.

  • 11.
    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.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Doncel, Maria
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jakobsson, U.
    Nyako, B. M.
    Jaworski, G
    Davies, P.
    De France, G.
    Kuti, I.
    Napoli, D. R.
    Wadsworth, R.
    Ghugre, S. S.
    Raut, R.
    Al-Azri, H.
    Algora, A.
    de Angelis, G.
    Atac, A.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Bäck, Torbjörn
    Boso, A.
    Clement, E.
    Debenham, D. M.
    Dombradi, Zs.
    Erturk, S.
    Gadea, A.
    Ghazi Moradi, Farnaz
    Gottardo, A.
    Huyuk, T.
    Ideguchi, E.
    Li, H.
    Michelagnoli, C.
    Modamio, V.
    Nyberg, J.
    Palacz, M.
    Petrache, C. M.
    Recchia, F.
    Sandzelius, M.
    Siciliano, M.
    Timar, J.
    Valiente-Dobon, J. J.
    Xiao, Z. G.
    M1 and E2 transition rates from core-excited states in semi-magic 94RuManuscript (preprint) (Other academic)
    Abstract [en]

    Lifetimes of high-spin states have been measured in the semi-magic (N=50) nucleus 94Ru. Excited states in 94Ru were populated in the 58Ni(40Ca, 4p)94Ru fusion-evaporation reaction at the Grand Accelerateur National d’Ions Lourds (GANIL) accelerator complex. DSAM lifetime analysis was performed on the Doppler broadened line shapes in energy spectra obtained from γ-rays emitted while the residual nuclei were slowing down in a thick 6 mg/cm2 metallic 58Ni target. In total eight excited-state lifetimes in the angular momentum range I = (13 − 20)ħ have been measured, five of which were determined for the first time. The deduced corresponding B(M1) and B(E2)reduced transition strengths are discussed within the framework of large-scale shell model calculations to study the contribution of different particle-hole configurations, in particular for analyzing contributions from core-excited configurations.

  • 12.
    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.
    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.
    et al.,
    Spectroscopy of the neutron deficient N=50 nucleus 95Rh2014Manuscript (preprint) (Other academic)
  • 13.
    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.

  • 14.
    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.

  • 15.
    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.

  • 16.
    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.

  • 17.
    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.

  • 18. Ralet, D
    et al.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Doncel, Maria
    KTH.
    Ghazi Moradi, Farnaz
    KTH.
    Zielinska, M.
    et al.,
    Lifetime measurement of neutron-rich even-even molybdenum isotopes2017In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 95, no 3, article id 034320Article in journal (Refereed)
    Abstract [en]

    Background: In the neutron-rich A approximate to 100 mass region, rapid shape changes as a function of nucleon number as well as coexistence of prolate, oblate, and triaxial shapes are predicted by various theoretical models. Lifetime measurements of excited levels in the molybdenum isotopes allow the determination of transitional quadrupole moments, which in turn provides structural information regarding the predicted shape change. Purpose: The present paper reports on the experimental setup, the method that allowed one to measure the lifetimes of excited states in even-even molybdenum isotopes from mass A = 100 up to mass A = 108, and the results that were obtained. Method: The isotopes of interest were populated by secondary knock-out reaction of neutron-rich nuclei separated and identified by the GSI fragment separator at relativistic beam energies and detected by the sensitive PreSPEC-AGATA experimental setup. The latter included the Lund-York-Cologne calorimeter for identification, tracking, and velocity measurement of ejectiles, and AGATA, an array of position sensitive segmented HPGe detectors, used to determine the interaction positions of the gamma ray enabling a precise Doppler correction. The lifetimes were determined with a relativistic version of the Doppler-shift-attenuation method using the systematic shift of the energy after Doppler correction of a gamma-ray transition with a known energy. This relativistic Doppler-shift-attenuation method allowed the determination of mean lifetimes from 2 to 250 ps. Results: Even-even molybdenum isotopes from mass A = 100 to A = 108 were studied. The decays of the low-lying states in the ground-state band were observed. In particular, two mean lifetimes were measured for the first time: tau = 29.7(-9.1)(+11.3) ps for the 4(+) state of Mo-108 and tau = 3.2(-0.7)(+ 0.7) ps for the 6(+) state of Mo-102. Conclusions: The reduced transition strengths B(E2), calculated from lifetimes measured in this experiment, compared to beyond-mean-field calculations, indicate a gradual shape transition in the chain of molybdenum isotopes when going from A = 100 to A = 108 with a maximum reached at N = 64. The transition probabilities decrease for Mo-108 which may be related to its well-pronounced triaxial shape indicated by the calculations.

  • 19. Sahin, E.
    et al.
    Doncel, Maria
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. University of Salamanca, Spain.
    Sieja, K.
    de Angelis, G.
    Gadea, A.
    Quintana, B.
    Gorgen, A.
    Modamio, V.
    Mengoni, D.
    Valiente-Dobon, J. J.
    John, P. R.
    Albers, M.
    Bazzacco, D.
    Benzoni, G.
    Birkenbach, B.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Clement, E.
    Curien, D.
    Corradi, L.
    Desesquelles, P.
    Dewald, A.
    Didierjean, F.
    Duchene, G.
    Eberth, J.
    Erduran, M. N.
    Farnea, E.
    Fioretto, E.
    de France, G.
    Fransen, C.
    Gernhaeuser, R.
    Gottardo, A.
    Hackstein, M.
    Hagen, T.
    Hernandez-Prieto, A.
    Hess, H.
    Hueyuek, T.
    Jungclaus, A.
    Klupp, S.
    Korten, W.
    Kusoglu, A.
    Lenzi, S. M.
    Ljungvall, J.
    Louchart, C.
    Lunardi, S.
    Menegazzo, R.
    Michelagnoli, C.
    Mijatovic, T.
    Million, B.
    Molini, P.
    Montagnoli, G.
    Montanari, D.
    Moeller, O.
    Napoli, D. R.
    Obertelli, A.
    Orlandi, R.
    Pollarolo, G.
    Pullia, A.
    Recchia, F.
    Reiter, P.
    Rosso, D.
    Rother, W.
    Salsac, M. -D
    Scarlassara, F.
    Schlarb, M.
    Siem, S.
    Singh, Pushpendra P.
    Soderstrom, P. -A
    Stefanini, A. M.
    Stezowski, O.
    Sulignano, B.
    Szilner, S.
    Theisen, Ch
    Ur, C. A.
    Yalcinkaya, M.
    Shell evolution beyond N=40: Cu-69,Cu-71,Cu-732015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 91, no 3, article id 034302Article in journal (Refereed)
    Abstract [en]

    The level structure of the neutron-rich Cu-69, Cu-71, and Cu-73 isotopes has been investigated by means of multinucleon transfer reactions. The experiment was performed at Laboratori Nazionali di Legnaro using the AGATA Demonstrator array coupled to the PRISMA magnetic spectrometer. Lifetimes of excited states in Cu nuclei were measured with the recoil-distance Doppler-shift method. The resulting electromagnetic matrix elements for transitions from excited states in Cu-69,Cu-71,Cu-73 nuclei are used to assess the collective or single-particle character of these states. The results are compared with predictions of large-scale shell-model calculations, giving further insight into the evolution of the proton pf shell as neutrons fill the 1g(9/2) orbital.

  • 20. Taylor, M. J.
    et al.
    Cullen, D. M.
    Procter, M. G.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Doncel, Maria
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Braunroth, T.
    Dewald, A.
    Pakarinen, J.
    Grahn, T.
    Greenlees, P. T.
    Auranen, K.
    Jakobsson, U.
    Julin, R.
    Juutinen, S.
    Herzan, A.
    Konki, J.
    Leino, M.
    Liotta, R.
    Partanen, J.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Saren, J.
    Sorri, J.
    Stolze, S.
    Uusitalo, J.
    Liang, W. Y.
    Xu, F. R.
    Competing single-particle and collective states in the low-energy structure of I-1132013In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 88, no 5, p. 054307-Article in journal (Refereed)
    Abstract [en]

    To understand the low-energy structure of the neutron deficient iodine isotopes, lifetimes for the low-lying 9/2(+) and 11/2(+) positive-parity states in I-113 have been measured as tau = 28(4) ps and tau = 3.7(7) ps, respectively. The lifetime for the 11/2(-) state, which feeds the 9/2(+) and 11/2(+) states, was remeasured with improved accuracy as tau = 216(7) ps. The reduced transition probability, B(E2) = 32(5) W.u., for the 9/2(+) -> 5/2(+) transition agrees with that calculated within the shell model using a Hamiltonian based on the charge-dependent Bonn nucleon-nucleon interaction. In contrast, the much larger transition probability, B(E2) = 209(39) W.u., measured for the 11/2(+) -> 7/2(+) transition has been interpreted, with the aid of configuration-constrained total Routhian surface calculations, as resulting from a slightly gamma-soft rotor with an associated quadrupole deformation of beta(2) approximate to 0.18. Remarkably similar reduced E1 transition probabilities of 5.5(5) x 10(-4) and 4.9(5) x 10(-4) W.u. were deduced for the 11/2(-) -> 9/2(+) and 11/2(-) -> 11/2(+) transitions, respectively, which feed apparently dissimilar but competing structures.

  • 21. Taylor, M. J.
    et al.
    Cullen, D. M.
    Procter, M. G.
    Smith, A. J.
    McFarlane, A.
    Twist, V.
    Alharshan, G. A.
    Ferreira, L. S.
    Maglione, E.
    Auranen, K.
    Grahn, T.
    Greenlees, P. T.
    Hauschild, K.
    Herzan, A.
    Jakobsson, U.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Konki, J.
    Leino, M.
    Lopez-Martens, A.
    Pakarinen, J.
    Partanen, J.
    Peura, P.
    Rahkila, P.
    Rinta-Antila, S.
    Ruotsalainen, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Stolze, S.
    Uusitalo, J.
    Doncel, Maria
    KTH, School of Engineering Sciences (SCI), Physics.
    Oblately deformed isomeric proton-emitting state in Lu-1512015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 91, no 4, article id 044322Article in journal (Refereed)
    Abstract [en]

    Gamma rays from excited states feeding a proton-emitting isomeric-state in Lu-151 have been observed for the first time. Comparison with state-of-the-art nonadiabatic quasiparticle calculations indicates an oblately deformed, 3/2(+) proton-emitting state with a quadrupole deformation of beta(2) = -0.11. The calculations suggest an increase in quadrupole deformation, to beta(2) = -0.18, with increasing spin which is understood in terms of the mixing of Nilsson states at the Fermi surface. It is also shown that the proton decay half-life is consistent with that from a 3/2(+) state with a quadrupole deformation of beta(2) = -0.12.

1 - 21 of 21
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