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  • 1. Akkoyun, S.
    et al.
    Algora, A.
    Alikhani, B.
    Ameil, F.
    de Angelis, G.
    Arnold, L.
    Astier, A.
    Ataç, Ayşe
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Aubert, Y.
    Aufranc, C.
    Austin, A.
    Aydin, S.
    Azaiez, F.
    Badoer, S.
    Balabanski, D. L.
    Barrientos, D.
    Baulieu, G.
    Baumann, R.
    Bazzacco, D.
    Beck, F. A.
    Beck, T.
    Bednarczyk, P.
    Bellato, M.
    Bentley, M. A.
    Benzoni, G.
    Berthier, R.
    Berti, L.
    Beunard, R.
    Lo Bianco, G.
    Birkenbach, B.
    Bizzeti, P. G.
    Bizzeti-Sona, A. M.
    Le Blanc, F.
    Blasco, J. M.
    Blasi, N.
    Bloor, D.
    Boiano, C.
    Borsato, M.
    Bortolato, D.
    Boston, A. J.
    Boston, H. C.
    Bourgault, P.
    Boutachkov, P.
    Bouty, A.
    Bracco, A.
    Brambilla, S.
    Brawn, I. P.
    Brondi, A.
    Broussard, S.
    Bruyneel, B.
    Bucurescu, D.
    Burrows, I.
    Buerger, A.
    Cabaret, S.
    Cahan, B.
    Calore, E.
    Camera, F.
    Capsoni, A.
    Carrio, F.
    Casati, G.
    Castoldi, M.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cercus, J. -L
    Chambert, V.
    El Chambit, M.
    Chapman, R.
    Charles, L.
    Chavas, J.
    Clement, E.
    Cocconi, P.
    Coelli, S.
    Coleman-Smith, P. J.
    Colombo, A.
    Colosimo, S.
    Commeaux, C.
    Conventi, D.
    Cooper, R. J.
    Corsi, A.
    Cortesi, A.
    Costa, L.
    Crespi, F. C. L.
    Cresswell, J. R.
    Cullen, D. M.
    Curien, D.
    Czermak, A.
    Delbourg, D.
    Depalo, R.
    Descombes, T.
    Desesquelles, P.
    Detistov, P.
    Diarra, C.
    Didierjean, F.
    Dimmock, M. R.
    Doan, Q. T.
    Domingo-Pardo, C.
    Doncel, M.
    Dorangeville, F.
    Dosme, N.
    Drouen, Y.
    Duchene, G.
    Dulny, B.
    Eberth, J.
    Edelbruck, P.
    Egea, J.
    Engert, T.
    Erduran, M. N.
    Erturk, S.
    Fanin, C.
    Fantinel, S.
    Farnea, E.
    Faul, T.
    Filliger, M.
    Filmer, F.
    Finck, Ch.
    de France, G.
    Gadea, A.
    Gast, W.
    Geraci, A.
    Gerl, J.
    Gernhaeuser, R.
    Giannatiempo, A.
    Giaz, A.
    Gibelin, L.
    Givechev, A.
    Goel, N.
    Gonzalez, V.
    Gottardo, A.
    Grave, X.
    Grebosz, J.
    Griffiths, R.
    Grint, A. N.
    Gros, P.
    Guevara, L.
    Gulmini, M.
    Goergen, A.
    Ha, H. T. M.
    Habermann, T.
    Harkness, L. J.
    Harroch, H.
    Hauschild, K.
    He, C.
    Hernandez-Prieto, A.
    Hervieu, B.
    Hess, H.
    Hueyuek, T.
    Ince, E.
    Isocrate, R.
    Jaworski, G.
    Johnson, Arne
    Jolie, J.
    Jones, P.
    Jonson, B.
    Joshi, P.
    Judson, D. S.
    Jungclaus, A.
    Kaci, M.
    Karkour, N.
    Karolak, M.
    Kaskas, A.
    Kebbiri, M.
    Kempley, R. S.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Klupp, S.
    Kogimtzis, M.
    Kojouharov, I.
    Korichi, A.
    Korten, W.
    Kroell, Th.
    Kruecken, R.
    Kurz, N.
    Ky, B. Y.
    Labiche, M.
    Lafay, X.
    Lavergne, L.
    Lazarus, I. H.
    Leboutelier, S.
    Lefebvre, F.
    Legay, E.
    Legeard, L.
    Lelli, F.
    Lenzi, S. M.
    Leoni, S.
    Lermitage, A.
    Lersch, D.
    Leske, J.
    Letts, S. C.
    Lhenoret, S.
    Lieder, R. M.
    Linget, D.
    Ljungvall, J.
    Lopez-Martens, A.
    Lotode, A.
    Lunardi, S.
    Maj, A.
    van der Marel, J.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Mariette, Y.
    Marginean, N.
    Marginean, R.
    Maron, G.
    Mather, A. R.
    Meczynski, W.
    Mendez, V.
    Medina, P.
    Melon, B.
    Menegazzo, R.
    Mengoni, D.
    Merchan, E.
    Mihailescu, L.
    Michelagnoli, C.
    Mierzejewski, J.
    Milechina, Larissa
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Million, B.
    Mitev, K.
    Molini, P.
    Montanari, D.
    Moon, S.
    Morbiducci, F.
    Moro, R.
    Morrall, P. S.
    Moeller, O.
    Nannini, A.
    Napoli, D. R.
    Nelson, L.
    Nespolo, M.
    Ngo, V. L.
    Nicoletto, M.
    Nicolini, R.
    Le Noa, Y.
    Nolan, P. J.
    Norman, M.
    Nyberg, J.
    Obertelli, A.
    Olariu, A.
    Orlandi, R.
    Oxley, D. C.
    Ozben, C.
    Ozille, M.
    Oziol, C.
    Pachoud, E.
    Palacz, M.
    Palin, J.
    Pancin, J.
    Parisel, C.
    Pariset, P.
    Pascovici, G.
    Peghin, R.
    Pellegri, L.
    Perego, A.
    Perrier, S.
    Petcu, M.
    Petkov, P.
    Petrache, C.
    Pierre, E.
    Pietralla, N.
    Pietri, S.
    Pignanelli, M.
    Piqueras, I.
    Podolyak, Z.
    Le Pouhalec, P.
    Pouthas, J.
    Pugnere, D.
    Pucknell, V. F. E.
    Pullia, A.
    Quintana, B.
    Raine, R.
    Rainovski, G.
    Ramina, L.
    Rampazzo, G.
    La Rana, G.
    Rebeschini, M.
    Recchia, F.
    Redon, N.
    Reese, M.
    Reiter, P.
    Regan, P. H.
    Riboldi, S.
    Richer, M.
    Rigato, M.
    Rigby, S.
    Ripamonti, G.
    Robinson, A. P.
    Robin, J.
    Roccaz, J.
    Ropert, J. -A
    Rosse, B.
    Rossi Alvarez, C.
    Rosso, D.
    Rubio, B.
    Rudolph, D.
    Saillant, F.
    Sahin, E.
    Salomon, F.
    Salsac, M. -D
    Salt, J.
    Salvato, G.
    Sampson, J.
    Sanchis, E.
    Santos, C.
    Schaffner, H.
    Schlarb, M.
    Scraggs, D. P.
    Seddon, D.
    Senyigit, M.
    Sigward, M. -H
    Simpson, G.
    Simpson, J.
    Slee, M.
    Smith, J. F.
    Sona, P.
    Sowicki, B.
    Spolaore, P.
    Stahl, C.
    Stanios, T.
    Stefanova, E.
    Stezowski, O.
    Strachan, J.
    Suliman, G.
    Soderstrom, P. -A
    Tain, J. L.
    Tanguy, S.
    Tashenov, Stanislav
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Theisen, Ch.
    Thornhill, J.
    Tomasi, F.
    Toniolo, N.
    Touzery, R.
    Travers, B.
    Triossi, A.
    Tripon, M.
    Tun-Lanoe, K. M. M.
    Turcato, M.
    Unsworth, C.
    Ur, C. A.
    Valiente-Dobon, J. J.
    Vandone, V.
    Vardaci, E.
    Venturelli, R.
    Veronese, F.
    Veyssiere, Ch.
    Viscione, E.
    Wadsworth, R.
    Walker, P. M.
    Warr, N.
    Weber, C.
    Weisshaar, D.
    Wells, D.
    Wieland, O.
    Wiens, A.
    Wittwer, G.
    Wollersheim, H. J.
    Zocca, F.
    Zamfir, N. V.
    Zieblinski, M.
    Zucchiatti, A.
    AGATA-Advanced GAmma Tracking Array2012In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 668, p. 26-58Article in journal (Refereed)
    Abstract [en]

    The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation gamma-ray spectrometer. AGATA is based on the technique of gamma-ray energy tracking in electrically segmented high-purity germanium crystals. This technique requires the accurate determination of the energy, time and position of every interaction as a gamma ray deposits its energy within the detector volume. Reconstruction of the full interaction path results in a detector with very high efficiency and excellent spectral response. The realisation of gamma-ray tracking and AGATA is a result of many technical advances. These include the development of encapsulated highly segmented germanium detectors assembled in a triple cluster detector cryostat, an electronics system with fast digital sampling and a data acquisition system to process the data at a high rate. The full characterisation of the crystals was measured and compared with detector-response simulations. This enabled pulse-shape analysis algorithms, to extract energy, time and position, to be employed. In addition, tracking algorithms for event reconstruction were developed. The first phase of AGATA is now complete and operational in its first physics campaign. In the future AGATA will be moved between laboratories in Europe and operated in a series of campaigns to take advantage of the different beams and facilities available to maximise its science output. The paper reviews all the achievements made in the AGATA project including all the necessary infrastructure to operate and support the spectrometer.

  • 2.
    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.

  • 3.
    Andgren, Karin
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    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.
    et al.,
    Excited states in the neutron-deficient nuclei Rn-197,Rn-199,Rn-2012008In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 77, no 5, p. 054303-1-054303-7Article in journal (Refereed)
    Abstract [en]

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

  • 4.
    Andgren, Karin
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Ganioglu, Ela
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Wyss, Ramon
    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.
    et al.,
    Low-spin collective behavior in the transitional nuclei Mo-86,Mo-882007In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 76, no 1, p. 014307-1-014307-9Article in journal (Refereed)
    Abstract [en]

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

  • 5. Ashrafi, S.
    et al.
    Lipoglavsek, M.
    Likar, A.
    Vidmar, T.
    Cederkall, J.
    Fahlander, C.
    Grawe, H.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Mitarai, S.
    Norlin, L. O.
    Nyberg, J.
    Palacz, M.
    Persson, J.
    Seweryniak, D.
    Shizuma, T.
    Sletten, G.
    Monte-Carlo simulation of the charged particle detector used in the NORDBALL gamma-ray spectrometer2001In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 458, no 3, p. 690-697Article in journal (Refereed)
    Abstract [en]

    The NORDBALL silicon detector array for detecting light charged particles emitted in fusion evaporation reactions was simulated with the Monte-Carlo method. The data from the reaction of 261 MeV Ni-58 ions with Cr-50 nuclei in a 4.8 mg/cm(2) thick target was used to adjust the simulation parameters. Relative population of residual nuclei in the reaction was determined, by comparing the intensities of gamma -rays.

  • 6.
    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.

  • 7.
    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.

  • 8.
    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.

  • 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.
    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.

  • 10.
    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.

  • 11.
    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.

  • 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, 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.

  • 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.
    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.

  • 14.
    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.

  • 15.
    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.

  • 16. Delion, D. S.
    et al.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto J.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics.
    Investigations of proton-neutron correlations close to the drip line2010In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 82, no 2, p. 024307-Article in journal (Refereed)
    Abstract [en]

    Proton-neutron correlations in nuclei above the Z = 50 shell closure are investigated with the aim of understanding the behavior of the 2(+) and 4(+) states in Te and Xe isotopes, which remain at a rather constant energy as one approaches the shell closure at N = 50. Our calculations reveal that standard quasiparticle random phase approximation calculations, involving a quadrupole-quadrupole (QQ) interaction with constant strengths, cannot explain this feature. It is found that to reproduce the experimental data within this model one has to include a variable proton-neutron interaction. It turns out that an increased proton-neutron QQ interaction increases the collectivity (i.e., B(E2) values) when approaching the N = 50 region, whereas an increased proton-neutron pairing interaction decreases the collectivity. We thus conclude that the ratio between the B(E2) value and 2(+) energy is a "fingerprint" of proton-neutron collectivity and it should be determined in future experiments concerning light Te isotopes. Based on this criterion, we conclude that the available experimental data indicate an enhanced proton-neutron pairing interaction by approaching doubly magic Z = N = 20 and Z = N = 28 regions.

  • 17. Fahlander, C.
    et al.
    Palacz, M.
    Rudolph, D.
    Sohler, D.
    Blomqvist, J.
    Lagergren, K.
    Norlin, L. O.
    Nyberg, J.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, A.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Wolinska, M.
    et al,
    Excited states in Sn-103: Neutron single-particle energies with respect to Sn-1002001In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 6302, no 2Article in journal (Refereed)
    Abstract [en]

    Gamma-ray lines from Sn-103 have been identified for the first time using EUROBALL and ancillary detectors. The level scheme of Sn-103 has been established by means of particle-gated gamma gamma coincidences. The energy spacing between the g(7/2) and d(5/2) neutron single-particle orbitals is determined from the excited states in Sn-103.

  • 18.
    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.

  • 19.
    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)
  • 20.
    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.

  • 21.
    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.

  • 22.
    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.

  • 23.
    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.

  • 24.
    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.

  • 25. 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.

  • 26.
    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.

  • 27.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Nuclear structure in the vicinity of the N = Z line in the A=90-100 region2002In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 13, no 02-jan, p. 9-14Article in journal (Refereed)
    Abstract [en]

    Neutron-deficient nuclei in the mass region A approximate to 90-100 exhibit a large variety of phenomena. In this region the heaviest N = Z nuclei are identified and enhanced neutron-proton correlations are expected when protons and neutrons occupy identical orbitals. A variety of nuclear shapes are predicted and observed for A less than or equal to 91, including superdeformed shapes. The nucleus Sn-100 is the heaviest N = Z doubly magic nucleus believed to be bound. Knowledge of the shell structure around 100Sn is of utmost importance for understanding the nuclear shell model. New results on both the N = Z nucleus Ru-88, superdeformed structures in A approximate to 90 nuclei as well as the first result on the level structure in Sn-103, and an extended level structure in In-102 are presented. The limitations of using stable beams and targets and the possibilities with new radioactive beams are briefly outlined.

  • 28.
    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.

  • 29.
    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.

  • 30.
    Lagergren, Karin
    et al.
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Clark, R. M.
    Fallon, P.
    Gorgen, A.
    Issa, Tomas
    KTH, Superseded Departments, Physics.
    Janssens, R. V. F.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Macchiavelli, A. O.
    Milechina, L.
    KTH, Superseded Departments, Physics.
    Sarantites, D. G.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Shape evolution in the superdeformed A approximate to 80-90 mass region2003In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 68, no 6, p. 643091-643095Article in journal (Refereed)
    Abstract [en]

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

  • 31.
    Lagergren, Karin
    et al.
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Clark, R. M.
    Fallon, P.
    Gorgen, A.
    Issa, Tomas
    KTH, Superseded Departments, Physics.
    Janssens, R. V. F.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Macchiavelli, A. O.
    Milechina, Larissa
    KTH, Superseded Departments, Physics.
    Sarantites, D. G.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Isospectral superdeformed bands in the N=46 nuclei Mo-88 and Tc-892004In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 21, no 3, p. 375-381Article in journal (Refereed)
    Abstract [en]

    Superdeformed bands in Mo-88 and Tc-89 were populated Using Ca-40-induced fusion-evaporation reactions on Ni-58 at a beam energy of 185 MeV. Gamma-rays emitted in the reactions were detected using the Gammasphere spectrometer, in coincidence with charged particles detected by the Microball array. A new superdeformed band was assigned to the nucleus Mo-88, leading to a revisit of earlier configuration assignments for superdeformed structures in this nucleus. In particular, the theoretical interpretation of a pair of identical (isospectral) superdeformed bands in Mo-88/Tc-89 is discussed. The configurations that are assigned to the four SD bands belonging to Mo-88 have properties that are predicted to be significantly affected by pair correlations.

  • 32. Palacz, M.
    et al.
    Fahlander, C.
    Sohler, D.
    Rudolph, D.
    Lagergren, K.
    Norlin, L. O.
    Nyberg, J.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, A.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Wolinska, M.
    et al,
    Investigations of neutron deficient nuclei close to Sn-100 with EUROBALL2001In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 32, no 3, p. 999-1003Article in journal (Refereed)
    Abstract [en]

    Excited states of nuclei in the vicinity of Sn-100 have been studied using: the EUROBALL detector array. Gamma-ray lines from Sn-103 have been identified for the first time, and a level scheme of low-lying excited states of Sn-103 has been established. New constraints on energies of single particle orbitals with respect to the Sn-100 core are obtained.

  • 33. Palacz, M
    et al.
    Seweryniak, D
    Atac, A
    Blomqvist, J
    CEDERWALL, BO
    KTH, Superseded Departments, Physics.
    Fahlander, C
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, Andreas
    KTH, Superseded Departments, Physics.
    Kownacki, J
    Norlin, L O
    Nyberg, J
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Ideguchi, E
    Julin, R
    Juutinen, S
    Mitarai, S
    Piiparinen, M
    Sletten, G
    Tormanen, S
    Virtanen, A
    In-beam gamma-ray spectroscopy of Co-561997In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 627, no 1, p. 162-174Article in journal (Refereed)
    Abstract [en]

    Excited states of Co-56 were studied in the reaction Al-27(S-32,2p1n) Co-56. The NORDBALL array with a Neutron Wall and a Silicon Ball was employed. The excited states were interpreted in terms of particle-hole excitations with respect to the doubly magic N = Z = 28 core.

  • 34. Pausch, G.
    et al.
    Prade, H.
    Sobiella, M.
    Schnare, H.
    Schwengner, R.
    Kaubler, L.
    Borcan, C.
    Ortlepp, H. G.
    Oehmichen, U.
    Grawe, H.
    Schubart, R.
    Gerl, J.
    Cederkall, J.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Moszynski, M.
    Wolski, D.
    Kapusta, M.
    Axelsson, A.
    Weiszflog, M.
    Hartlein, T.
    Pansegrau, D.
    de Angelis, G.
    Ashrafi, S.
    Likar, A.
    Lipoglavsek, M.
    RoSiB - a 4 pi silicon ball for charged-particle detection in EUROBALL2000In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 443, no 03-feb, p. 304-318Article in journal (Refereed)
    Abstract [en]

    A 4 pi silicon bail for detection and identification of light charged particles in large multidetector gamma-arrays as EUROBALL is presented. The design is based on a N = 42 ball with 12 pentagons and 30 hexagons as used in the GASP array. The absorptive material for gamma-rays is minimized to the detector thickness of 300 or 500 mu m and a 0.63 mm ceramic backing. The geometrical coverage is designed for about 90% of 4 pi. A pulse shape discrimination method with totally depleted detectors working in the reverse mount allows identifying protons and alpha-particles above an energy threshold of about 2 MeV. The performances of the ball were rested at the tandem - booster accelerator combination of the MPI Heidelberg in two experiments using the high-recoil reaction of 228 MeV Ni-58 + Ti-46 and the low-recoil reaction of 95 MeV O-16 + Ni-58. The two-dimensional spectra of zero-crossing (ZC) versus energy confirmed an excellent discrimination of protons and alpha-particles in all the detectors at different angles. The energy spectra of protons and alpha-particles measured in the experiments are presented. too. The gamma-spectra measured in coincidence with various combinations of emitted particles showed a high selectivity of the ball. The reduced total efficiency for protons of 59% and 55% and alpha-particles of 44% and 32% measured in a nuclear spectroscopy application is analyzed in a Monte-Carlo simulation (GEANT). It is due to a combined influence of a thick target needed to stop the recoiling residual nuclei and thick absorbers needed to protect the Si-detectors from scattered beam. The results along with the GEANT extrapolation to optimum experimental conditions confirm that RoSiB is a highly efficient and selective device for identification of rare reaction channels with heavy ions.

  • 35. Perez, G. E.
    et al.
    Sohler, D.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Cederkall, J.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, A.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Norlin, L. O.
    Nyberg, J.
    et al,
    Structure of high-spin states in Pd-1002001In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 686, p. 41-63Article in journal (Refereed)
    Abstract [en]

    High-spin states of the neutron deficient (100)pd nucleus have been investigated via the Cr-50(Ni-58, 4p alpha) and Zn-70(S-36,6n) heavy-ion induced reactions. For the detection of evaporated particles and gamma rays the NORDBALL array equipped with ancillary detectors and the EUROGAM II detector system were utilized. By the use of in-beam spectroscopic methods 89 transitions belonging to (100)pd have been observed, 49 of which were identified for the first time. The level scheme has been extended up to E-X approximate to 16 MeV excitation energy and I approximate to 25h. The experimental results were compared with the predictions of cranked shell model calculations. Maximal spin alignments were found in the (pig(9/2))(12+)(-4) (vd(5/2),g(7/2)(3)h(11/2))(13-) and (pig(9/2)(-3)p(1/2))(11-)(vd(5/2)g(7/2)(3)h(11/2))(13-) configurations. Possible existence of octupole correlations is discussed on the basis of 6 (E 1)lB(E2) values deduced for the decays of high-spin levels in the yrast negative-parity band.

  • 36.
    Qi, Chong
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Blomqvist, Jan
    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.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Coherence features of the spin-aligned neutron-proton pair coupling scheme2012In: Physica scripta. T, ISSN 0281-1847, Vol. T150, p. 014031-Article in journal (Refereed)
    Abstract [en]

    The seniority scheme has been shown to be extremely useful for the classification of nuclear states in semi-magic nuclei. The neutron-proton (np) correlation breaks the seniority symmetry in a major way. As a result, the corresponding wave function is a mixture of many components with different seniority quantum numbers. In this paper, we show that the np interaction may favor a new kind of coupling in N = Z nuclei, i.e. the so-called isoscalar spin-aligned np pair mode. Shell model calculations reveal that the ground and low-lying yrast states of the N = Z nuclei Pd-92 and Cd-96 may be mainly built upon such spin-aligned np pairs, each carrying the maximum angular momentum J = 9 allowed by the shell 0 g(9/2) which is dominant in this nuclear region.

  • 37.
    Qi, Chong
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Blomqvist, Jan
    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.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Spin-aligned neutron-proton pair mode in atomic nuclei2011In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 84, no 2, p. 021301-Article in journal (Refereed)
    Abstract [en]

    Shell-model calculations using realistic interactions reveal that the ground and low-lying yrast states of the N = Z nucleus (92)(46)Pd are mainly built upon isoscalar neutron-proton pairs, each carrying the maximum angular momentum J = 9 allowed by the shell 0g(9/2), which is dominant in this nuclear region. This structure is different from that found in the ground and low-lying yrast states of all other even-even nuclei studied so far. The low-lying spectrum of excited states generated by such correlated neutron-proton pairs has two distinctive features: (i) the levels are almost equidistant at low energies and (ii) the transition probability I -> I - 2 is approximately constant and strongly selective. This unique mode is shown to replace normal isovector pairing as the dominant coupling scheme in N = Z nuclei approaching the doubly magic nucleus (100)Sn.

  • 38.
    Sandzelius, Mikael
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cedervall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ganioglu, Ela
    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.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    (gamma)-ray spectroscopy of 163Ta2009In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 80, no 5, p. 054316-Article in journal (Refereed)
    Abstract [en]

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

  • 39.
    Sandzelius, Mikael
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ganioǧlu, Ela
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hadinia, Baharak
    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.
    Grahn, T.
    Greenlees, P. T.
    Jakobsson, U.
    Johnson, Arne S.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Leino, M.
    Nyman, M.
    Peura, P.
    Rahkila, P.
    Sánre, J.
    Scholey, C.
    Sorri, J.
    Uusitalo, J.
    Wyss, Ramon A.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Probing the collective degrees of freedom at the proton drip line in the extremely neutron deficient 172Hg2011In: AIP Conf. Proc., 2011, p. 29-34Conference paper (Refereed)
    Abstract [en]

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

  • 40.
    Sandzelius, Mikael
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ganioglu, Ela
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hadinia, Bahrak
    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.
    Johnson, Arne
    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.
    First observation of excited states in Hg-1722009In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 79, no 6, p. 064315-Article in journal (Refereed)
    Abstract [en]

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

    .

     

  • 41.
    Sandzelius, Mikael
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Scholey, Catherine
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Ganioglu, Ela
    KTH, School of Engineering Sciences (SCI), Physics.
    Andgren, Karin
    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, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Lagergren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    First identification of excited states in 169Ir2007In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 75, no 5, p. 054321-Article in journal (Refereed)
    Abstract [en]

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

  • 42. Sohler, D.
    et al.
    Cederkäll, Joakim
    KTH, Superseded Departments, Physics.
    Ataç, Ayşe
    Department of Physics, Ankara University, 06100 Tandogan, Ankara, Turkey.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, Andras
    KTH, Superseded Departments, Physics.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Norlin, Lars Olov
    KTH, Superseded Departments, Physics.
    Weiszflog, M.
    et, al
    Band-terminating states in Ag-1012004In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 733, no 02-jan, p. 37-52Article in journal (Refereed)
    Abstract [en]

    Excited states of the neutron deficient Ag-101 nucleus have been investigated via the Cr-50(Ni-58, 3rho1alpha) heavy-ion induced reaction at 261 meV by use of in-beam spectroscopic methods. On the basis of the measured gammagamma-cincidence relations and angular distribution ratios high-spin bands have been extended up to I-pi = 35/2(+), 45/2((-)) and (49/2(-)). The negative parity states at the highest energy have been interpreted as terminating non-collective oblate states in the framework of the Nilsson-Strutinsky cranking formalism.

  • 43. Sohler, D.
    et al.
    Dombradi, Z.
    Blomqvist, J.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, A.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Norlin, L. O.
    Nyberg, J.
    et al,
    Maximally aligned states in Ag-992003In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 16, no 2, p. 171-175Article in journal (Refereed)
    Abstract [en]

    Excited states of Ag-99 were populated via the Cr-50 + Ni-58 (261 MeV) reaction using the NORDBALL detector array equipped with charged-particle and neutron. detector systems for reaction channel separation. On the basis of the measured gammagamma-coincidence relations and angular distribution ratios a significantly extended level scheme has been constructed up to E-x similar to 7.8 MeV and I = 35/2. The experimental results were described within the framework of the shell model. Candidates for states fully aligned in the pig(9/2)(-3)nu(d(5/2),g(7/2))(2) valence configuration space were found at 4109 and 6265 keV.

  • 44. Sohler, D.
    et al.
    Palacz, M.
    Dombradi, Z.
    Hjorth-Jensen, M.
    Fahlander, C.
    Norlin, L. O.
    KTH, School of Engineering Sciences (SCI), Physics.
    Nyberg, J.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Lagergren, K.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederkäll, J
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Kerek, A.
    KTH, School of Engineering Sciences (SCI), Physics.
    Klamra, Wlodzimierz
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Wolinska, M.
    et al, .
    Maximally aligned states in the proton drip line nucleus Sb-1062005In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 753, no 04-mar, p. 251-262Article in journal (Refereed)
    Abstract [en]

    High-spin states in Sb-106 have been investigated in the Fe-54(Ni-58, 1α 1p1n) reaction by in-beam γ-spectroscopic methods using the EUROBALL detector array equipped with charged particle and neutron detectors. On the basis of measured γγ-coincidence relations, angular distributions, and linear polarization ratios a significantly extended level scheme has been constructed up to spin and parity I-π = (19(-)) and E-x ∼ 6.5 MeV. The experimental results are interpreted within the framework of the gdsh shell model using a realistic effective nucleon-nucleon interaction. Candidates for states with fully aligned angular momenta in the π(d(5/2), g(7/2))(1) v (d(5/2), g(7/2))(5) valence space are identified at 4338 and 5203 keV, as well as in the π(d(5/2), g(7/2))(1) V(d(5/2), g(7/2))(4)h(11/2)(1) space at 6087, 6573 and 6783 keV. © 2005 Elsevier B.V. All rights reserved.

  • 45. Sohler, D.
    et al.
    Palacz, M.
    Dombradi, Z.
    Norlin, L. O.
    Nyberg, J.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Lagergren, K.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Kerek, A.
    Klamra, Wlodzimierz
    KTH, Superseded Departments, Physics.
    Wolinska, M.
    et al, .
    Neutron excitations across the N=50 shell gap in In-1022002In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 708, no 04-mar, p. 181-189Article in journal (Refereed)
    Abstract [en]

    The structure of In-102 has been investigated by in-beam gamma-spectroscopic methods. Knowledge on the excited states of this nucleus has significantly been extended. Three cascades of transitions were observed to exceed the spin-energy domain spanned by the pig(9/2)(-1)v(d(5/2),g(7/2))(3) configurations. The new high spin states at similar to 4 MeV excitation energy could be assigned to the pig(9/2)(-1)v(d(5/2), g(7/2))(2)h (11/2) configuration, while at least those at 4.733, 5.192 and 5.853 MeV most likely arise from the vg(9/2) --> vd(5/2), g(7/2) one-particle-one-hole excitation across the N = 50 shell closure.

  • 46. Sohler, Dola
    et al.
    Lagergren, Karin
    KTH, Superseded Departments, Physics.
    Blomqvist, Jan
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Hadinia, Baharak
    KTH, Superseded Departments, Physics.
    Milechina, Larissa
    KTH, Superseded Departments, Physics.
    Timaar, J.
    de Angelis, G.
    Bednarczyk, P.
    Curien, D.
    Gadea, A.
    Nyberg, J.
    First identification of excited states in the T-z=1/2 nucleus Pd-932004In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 19, no 2, p. 169-172Article in journal (Refereed)
    Abstract [en]

    The first experimental information about excited states in the N=Z+1 nucleus Pd-93 is presented. The experiment was performed using a 205 MeV Ni-58 beam from the Vivitron accelerator at IReS, Strasbourg, impinging on a bismuth-backed Ca-40 target. Gamma-rays, neutrons and charged particles emitted in the reactions were detected using the Ge detector array Euroball, the Neutron Wall liquid-scintillator array and the Euclides Si charged-particle detector system. The experimental level scheme is compared with the results of new shell model calculations which predict a coupling scheme with aligned neutron-proton pairs to greatly influence the level structure of Napproximate toZ nuclei at low excitation energies.

1 - 46 of 46
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