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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. Caceres, L.
    et al.
    Gorska, M.
    Jungclaus, A.
    Pfutzner, M.
    Grawe, H.
    Nowacki, F.
    Sieja, K.
    Pietri, S.
    Rudolph, D.
    Podolyak, Zs.
    Regan, P. H.
    Werner-Malento, E.
    Detistov, P.
    Lalkovski, S.
    Modamio, V.
    Walker, J.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics.
    Bednarczyk, P.
    Benlliure, J.
    Benzoni, G.
    Bruce, A. M.
    Casarejos, E.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Crespi, F. C. L.
    Doornenbal, P.
    Geissel, H.
    Gerl, J.
    Grebosz, J.
    Hadinia, Bahrak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hellstrom, M.
    Hoischen, R.
    Ilie, G.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Kmiecik, M.
    Kojouharov, I.
    Kumar, R.
    Kurz, N.
    Maj, A.
    Mandal, S.
    Montes, F.
    Martinez-Pinedo, G.
    Myalski, S.
    Prokopowicz, W.
    Schaffner, H.
    Simpson, G. S.
    Steer, S. J.
    Tashenov, S.
    Wieland, O.
    Wollersheim, H. J.
    Spherical proton-neutron structure of isomeric states in Cd-1282009In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 79, no 1, p. 011301-Article in journal (Refereed)
    Abstract [en]

    The gamma-ray decay of isomeric states in the even-even nucleus Cd-128 has been observed. The nucleus of interest was produced both by the fragmentation of Xe-136 and the fission of U-238 primary beams. The level scheme was unambiguously constructed based on.. coincidence relations in conjunction with detailed lifetime analysis employed for the first time on this nucleus. Large-scale shell-model calculations, without consideration of excitations across the N = 82 shell closure, were performed and provide a consistent description of the experimental level scheme. The structure of the isomeric states and their decays exhibit coexistence of proton, neutron, and strongly mixed configurations due to p. interaction in overlapping orbitals for both proton and neutron holes.

  • 6.
    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.

  • 7.
    Cederwall, Bo
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Sandzelius, Mikael
    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.
    Evidence for enhanced collectivity in Te-I-Xe nuclei near the N=Z=50 double shell closure2007In: PROTON EMITTING NUCLEI AND RELATED TOPICS / [ed] Ferreira, LS; Arumugam, P, MELVILLE, USA: AMER INST PHYSICS , 2007, Vol. 961, p. 156-162Conference paper (Refereed)
    Abstract [en]

    Gamma-ray transitions have been identified for the first time in the extremely neutron-deficient T-z = 1 nuclide Xe-110 and the energies of the three lowest excited states in the ground-state band have been deduced. A level scheme has also been constructed for the proton-unbound, T-z = 3/2 nuclide I-109, exhibiting band structures built on g(7/2) and h(11/2) states in a weakly deformed, triaxial nucleus. In addition, a third band is proposed to be bui It oil a g(7/2) orbital coupled to an octupole-vibrational phonon of the Te-108 core. The results were obtained in a recoil-decay tagging experiment using the Ni-58(Fe-54,2n/p2n) reaction at a beam energy of 195 MeV. The experiment was performed using the highly efficient JUROGAM y-ray spectrometer in conjunction with the RITU gas-filled recoil separator and the GREAT focal -plane spectrometer. The results on Xe-110 establish a breaking of the normal trend of increasing first excited 2(+) and 4(+) level energies as a function of decreasing neutron number as the N = 50 major shell gap is approached for the neutron-deficient Xe isotopes. This unusual feature is suggested to be an effect of enhanced collectivity, possibly arising from isoscalar n-p interactions becoming increasingly important close to the N = Z line. Features in the low-lying levels of Te-106 and I-109, showing similar trends, are also discussed.

  • 8.
    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.

  • 9. Gorska, M.
    et al.
    Caceres, L.
    Grawe, H.
    Pfuetzner, M.
    Jungclaus, A.
    Pietri, S.
    Werner-Malento, E.
    Cederwall, Bo
    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.
    Evolution of the N=82 shell gap below Sn-132 inferred from core excited states in In-1312009In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 672, no 4-5, p. 313-316Article in journal (Refereed)
    Abstract [en]

    The gamma-ray decay of ail excited state in In-131, the one proton hole neighbor of the doubly magic (132)sn has been measured. A high-spin, core-excited isomer with T-1/2 = 630(60) us was identified following production by both relativistic fragmentation of a Xe-136 beam and fission Of a U-238 beam. This state deexcites by a single gamma-ray branch of 3782(2) keV from which direct evidence for the size of the N = 82 shell gal) is inferred. The results are discussed in comparison to a shell-model Calculation including configurations across the closed shells at N = 82 and Z = 50.

  • 10.
    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.

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

    The neutron-deficient nucleus At-199 has been studied through gamma-ray and electron spectroscopy, using the recoil-decay tagging technique. Two experiments were conducted, using a gas-filled recoil separator with a focal-plane spectrometer alone and together with a germanium-detector array at the target position. The resulting level scheme for 199At includes a new isomer with a half-life of 0.80(5) mu s and a spin and parity of (29/2(+)). The 13/2(+) isomer, which de-excites via an M2 transition to the 9/2 ground state, was measured to have a half-life of 70(20) ns. Our earlier version of the level scheme for At-197 has been updated as well.

  • 12.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics.
    Applications of Pulse Shape Analysis Techniques for Segmented Planar Germanium Detectors2007Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The application of pulse shape analysis (PSA) and γ-ray tracking techniques has attracted a great deal of interest in the recent years in fields ranging from nuclear structure studies to medical imaging. These new data analysis methods add position sensitivity as well as directional information for the detected γ-rays to the excellent energy resolution of germanium detectors. This thesis focuses on the application of PSA on planar segmented germanium detectors, divided into three separate studies. The pulse shape analysis technique known as the matrix method was chosen due to its ability to treat events with arbitrary number and combinations of interactions within a single detector. It has been applied in two experiments with the 25-fold segmented planar pixel detector -- imaging and polarization measurements -- as well as in a simulation of upcoming detectors for DESPEC at NuSTAR/FAIR.

    In the first experiment, a point source of 137Cs was imaged. Events where the 662 keV γ-rays scattered once and were then absorbed in a different segment were treated by the PSA algorithm in order to find the locations of these interactions. The Compton scattering formula was then used to determine the direction to the source. The experiment has provided a robust test of the performance of the PSA algorithm on multiple interaction events, in particular those with interactions in adjacent segments, as well as allowed to estimate the realistically attainable position resolution. In the second experiment, the response of the detector to polarized photons of 288 keV was studied. The polarization of photons can be measured through the observation of the angular distribution of Compton-scattered photons, Hence the ability to resolve the interaction locations had once again proven useful.

    The third study is focused on the performance of the proposed planar germanium detectors for the DESPEC array. As these detectors have not yet been manufactured at the time of this writing, a set of data simulated in GEANT4 was used. The detector response was calculated for two of the possible segmentation patterns -- that with a single pixelated contact and one where both contacts are segmented into mutually orthogonal strips. In both cases, PSA was applied in order to reconstruct the interaction locations from this response. It was found that the double-sided strip detector can achieve an over-all better position resolution with a given number of readout channels. However, this comes at the expense of a small number of complex events where the reconstruction fails. These results have also been compared to the performance of the 25-fold pixelated detector.

  • 13.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics.
    Position-sensitive germanium detectors for gamma-ray tracking, imaging and polarimetry2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Modern germanium detectors are often manufactured with two-dimensionally segmented electrical contacts. Signals induced in each segment are read out simultaneously when a photon is detected. Detailed pulse shape analysis (PSA) of these signals allows to resolve positions of individual γ-ray interactions with a precision of at least a few mm. The track of a photon can then be reconstructed using γ-ray tracking. Using these techniques, highly efficient large-volume germanium detectors can replace detector systems where previously highly granulated detector arrays were required, and/or large fractions of photons had to be rejected. The ability to reconstruct the direction of an incoming photon and its scattering path makes it possible to use segmented detectors for γ-ray imaging and polarimetry. Doppler correction of photon energies in experiments where γ rays are emitted from fast ion beams can be greatly improved due to improved determination of the emission angle with respect to the beam. Furthermore, arrays of many detectors can be built without the need for conventional anticoincidence detectors for escape suppression. Instead, photons escaping a detector crystal can be tracked through neighbouring ones.

    In this work position reconstruction accuracy was evaluated for segmented detectors in a number of geometries in realistic applications. Particular emphasis has been put on the reconstruction of data sets containing events of arbitrary complexity in terms of the number of hit segments and interactions per segment. The imaging and polarization sensitivities of a single planar germanium pixel detector have been evaluated experimentally. In these measurements, photons absorbed in two, often adjacent, segments were reconstructed. Simulated interactions of γ-rays with the detectors of the proposed DESPEC germanium array were analysed yielding the position resolution obtainable in realistic experimental situations, as well as its dependence on photon energy, event complexity, noise and other sources of error.

  • 14.
    Khaplanov, Anton
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Tashenov, Stanislav
    KTH, School of Engineering Sciences (SCI), Physics.
    Position sensitivity of segmented planar HPGe detectors for the DESPEC project at FAIR2008In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 592, p. 325-333Article in journal (Refereed)
    Abstract [en]

    One of the proposed germanium detector systems for the upcoming DESPEC array at the FAIR facility consists of triple modules of electrically segmented planar high-purity germanium detectors. In this work, the position sensitivity obtained by means of pulse shape analysis (PSA) for simulated gamma-ray interactions has been studied for the possible segmentation patterns for such detectors-the double-sided strip detector (DSSD) and the one-sided pixelated geometry. An over-all similar number of readout channels has been considered for each case, resulting in 8 + 8 strips and 16 pixels. It has been found that the higher physical granularity of the DSSD results in a significantly higher position resolution, as well as in a somewhat lower probability of merging multiple interaction points. A drawback of the DSSD geometry is the inability to assign the interactions to the correct voxels for certain complex multiple interaction patterns. This effect has been studied in detail. Finally, a comparison has been made with the existing 25-pixel planar detector at KTH [A. Khaplanov, et al., Nucl. Instr. and Meth. A 580 (2007) 1075; L. Milechina, B. Cederwall, Nucl. Instr. and Meth. A 550 (2005) 278)].

  • 15.
    Khaplanov, Anton
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Pettersson, Jonas
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Compton imager based on a single planar segmented HPGe detector2007In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 580, p. 1075-1078Article in journal (Refereed)
    Abstract [en]

    A collimator-free Compton imaging system has been developed based on a single high-purity germanium detector and used to generate images of radioactive sources emitting gamma rays. The detector has a planar crystal with one pixellated contact with a total of 25 segments. Pulse shape analysis has been applied to achieve a 3D-position sensitivity of the detector. The first imaging results from this detector are presented, based on the reconstruction of events where a gamma ray is fully absorbed after scattering between adjacent segments.

  • 16.
    Khaplanov, Anton
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Tashenov, Stanislav
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Position sensitivity of the proposed segmented germanium detectors for the DESPEC project2009In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 604, no 1/2, p. 56-59Article in journal (Refereed)
    Abstract [en]

    The DESPEC HPGe array is a part of the NuSTAR project at FAIR, Germany. It is aimed at the spectroscopy of the stopped decaying exotic nuclei. Segmented gamma-ray tracking detectors are proposed for this array in order to maximize detection efficiency and background suppression when searching for very rare events. Two types of detector modules-stacks of three 16-fold segmented planar crystals and 12- and 16-fold segmented clover detectors-have been investigated and compared from the point of view of the achievable position resolution using pulse shape analysis (PSA). To this end, detector signals from realistic gamma-ray interactions have been calculated. These signals were treated by PSA in order to reconstruct the photon interaction locations. Comparing the initial interaction locations to the reconstructed ones, it was found that the double-sided strip planar detector yielded position reconstruction errors at least a factor 2 lower than the other detectors considered

  • 17.
    Khaplanov, Anton
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Tashenov, Stanislav
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Jaworski, Grzegorz
    Warsaw University of Technology.
    A gamma-ray polarimeter based on a single segmented planar HPGe detector2008In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 593, no 3, p. 459-465Article in journal (Refereed)
    Abstract [en]

    The polarization sensitivity of a segmented planar HPGe detector has been measured. For this purpose 662 keV photons from a Cs-137 source which were Compton scattered at approximate to 90 degrees in a coaxial germanium detector were utilized as a source of partially linearly polarized gamma radiation of the energy; approximate to 288 keV. The detector has a 50 x 50 x 21 mm sensitive volume and 5 x 5 electrical segmentation of the cathode contact. The degree of linear polarization is determined through the analysis of the directions of Compton scatterings inside the detector. The locations of the Compton scattering interactions and of the subsequent photo-absorption interactions have been determined with the help of pulse shape analysis (PSA), provided that these interactions are in two different segments of the planar detector. A comparison with a polarization analysis using the position resolution defined by the physical segmentation (without the use of PSA) was also performed. It is demonstrated that the use of PSA enables a much higher polarization sensitivity for events where the 288 keV photons scatter between adjacent pixels. Such events constitute 90% of the data for the 288 keV photons and are even more important for gamma-rays of lower energies.

  • 18. Lalkovski, S.
    et al.
    Bruce, A. M.
    Jungclaus, A.
    Gorska, M.
    Pfuetzner, M.
    Caceres, L.
    Naqvi, F.
    Pietri, S.
    Podolyak, Zs.
    Simpson, G. S.
    Andgren, Karin
    KTH.
    Bednarczyk, P.
    Beck, T.
    Benlliure, J.
    Benzoni, G.
    Casarejos, E.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Crespi, F. C. L.
    Cuenca-Garcia, J. J.
    Cullen, I. J.
    Bacelar, A. M. Denis
    Detistov, P.
    Doornenbal, P.
    Farrelly, G. F.
    Garnsworthy, A. B.
    Geissel, H.
    Gelletly, W.
    Gerl, J.
    Grebosz, J.
    Hadinia, Baharak
    KTH.
    Hellström, M.
    Hinke, C.
    Hoischen, R.
    Ilie, G.
    Jaworski, G.
    Jolie, J.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Kisyov, S.
    Kmiecik, M.
    Kojouharov, I.
    Kumar, R.
    Kurz, N.
    Maj, A.
    Mandal, S.
    Modamio, V.
    Montes, F.
    Myalski, S.
    Palacz, M.
    Prokopowicz, W.
    Reiter, P.
    Regan, P. H.
    Rudolph, D.
    Schaffner, H.
    Sohler, D.
    Steer, S. J.
    Tashenov, S.
    Walker, J.
    Walker, P. M.
    Weick, H.
    Werner-Malento, E.
    Wieland, O.
    Wollersheim, H. J.
    Zhekova, M.
    Core-coupled states and split proton-neutron quasiparticle multiplets in Ag122-1262013In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 87, no 3, p. 034308-Article in journal (Refereed)
    Abstract [en]

    Neutron-rich silver isotopes were populated in the fragmentation of a Xe-136 beam and the relativistic fission of U-238. The fragments were mass analyzed with the GSI Fragment Separator and subsequently implanted into a passive stopper. Isomeric transitions were detected by 105 high-purity germanium detectors. Eight isomeric states were observed in Ag122-126 nuclei. The level schemes of Ag-122,Ag-123,Ag-125 were revised and extended with isomeric transitions being observed for the first time. The excited states in the odd-mass silver isotopes are interpreted as core-coupled states. The isomeric states in the even-mass silver isotopes are discussed in the framework of the proton-neutron split multiplets. The results of shell-model calculations, performed for the most neutron-rich silver nuclei are compared to the experimental data.

  • 19. Naqvi, F.
    et al.
    Gorska, M.
    Caceres, L.
    Jungclaus, A.
    Pfuetzner, M.
    Grawe, H.
    Nowacki, F.
    Sieja, K.
    Pietri, S.
    Werner-Malento, E.
    Regan, P. H.
    Rudolf, D.
    Podolyak, Z.
    Jolie, J.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Beck, T.
    Bednarczyk, P.
    Benlliure, J.
    Benzoni, G.
    Bruce, A. M.
    Casarejos, E.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Crespi, F. C. L.
    Detistov, P.
    Dombradi, Zs.
    Doornenbal, P.
    Geissel, H.
    Gerl, J.
    Grebosz, J.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hellstrom, M.
    Hoischen, R.
    Ilie, G.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Kojouharov, I.
    Kmiecik, M.
    Kurz, N.
    Lalkovski, S.
    Maj, A.
    Mandal, S.
    Modamio, V.
    Montes, F.
    Myalski, S.
    Prokopowicz, W.
    Reiter, P.
    Schaffner, H.
    Simpson, G.
    Sohler, D.
    Steer, S. J.
    Tashenov, S.
    Walker, J.
    Wieland, O.
    Wollersheim, H. J.
    Isomer spectroscopy of (127)Cd2010In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 82, no 3, p. 034323-Article in journal (Refereed)
    Abstract [en]

    The spin and configurational structure of excited states of (127)Cd, the two-proton and three-neutron hole neighbor of (132)Sn, has been studied. An isomeric state with a half-life of 17.5(3) mu s was populated in the fragmentation of a (136)Xe beam on a (9)Be target at a beam energy of 750 MeV/u. Time distributions of the delayed gamma transitions and gamma gamma coincidence relations were exploited to construct a decay scheme. The observed yrast (19/2)(+) isomer is proposed to have dominant configurations of nu(h(11/2)(-3))pi(g(9/2)(-1), p(1/2)(-1)), nu(h(11/2)(-2)d(3/2)(-1))pi(g(9/2)(-2)), and nu(h(11/2)(-2), s(1/2)(-1))pi(g(9/2)(-2)) and to decay by two competing stretched M2 and E3 transitions. Experimental results are compared with the isotone (129)Sn. The new information provides input for the proton-neutron interaction and the evolution of neutron hole energies in nuclei around the doubly magic (132)Sn core.

  • 20. Pietri, S.
    et al.
    Jungclaus, A.
    Gorska, M.
    Grawe, H.
    Pfuetzner, M.
    Caceres, L.
    Detistov, P.
    Lalkovski, S.
    Modamio, V.
    Podolyak, Z.
    Regan, P. H.
    Rudolph, D.
    Walker, J.
    Werner-Malento, E.
    Bednarczyk, P.
    Doornenbal, P.
    Geissel, H.
    Gerl, J.
    Grebosz, J.
    Kojouharov, I.
    Kurz, N.
    Prokopowicz, W.
    Schaffner, H.
    Wollersheim, H. J.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Benlliure, J.
    Benzoni, G.
    Bruce, A. M.
    Casarejos, E.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Crespi, F. C. L.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hellström, M.
    Hoischen, R.
    Ilie, G.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Kmiecik, M.
    Kumar, R.
    Maj, A.
    Mandal, S.
    Montes, F.
    Myalski, S.
    Simpson, G.
    Steer, S. J.
    Tashenov, S.
    Wieland, O.
    First observation of the decay of a 15(-) seniority v=4 isomer in Sn-1282011In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 83, no 4, p. 044328-Article in journal (Refereed)
    Abstract [en]

    Isomeric states in the semimagic Sn128-130 isotopes were populated in the fragmentation of a Xe-136 beam on a Be-9 target at an energy of 750 A.MeV. The decay of an isomeric state in Sn-128 at an excitation energy of 4098 keV has been observed. Its half live has been determined to be T-1/2 = 220(30) ns from the time distributions of the delayed gamma rays emitted in its decay. gamma gamma coincidence relations were analyzed in order to establish the decay pattern of the newly established state toward the known (7(-)) and (10(+)) isomers at excitation energies of 2092 and 2492 keV, respectively. Based on a comparison with results of state-of-the-art shell-model calculations the new isomeric state is proposed to have the nu h(11/2)(-3)d(3/2)(-1) configuration with the four neutron holes in Sn-132 maximally aligned to a total spin of I-pi = 15(-).

  • 21.
    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.

  • 22.
    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.

  • 23.
    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.

    .

     

  • 24.
    Sandzelius, Mikael
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon A
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Indentification of Excited States in the Tz=1 Nucleus 110Xe: Evidence for Enhanced Collectivity Near the N=Z=50 Double Shell Closure2007In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 99, p. 022501-Article in journal (Refereed)
    Abstract [en]

    Gamma-ray transitions have been identified for the first time in the extremely neutron-deficient (N=Z+2) nucleus Xe110, and the energies of the three lowest excited states in the ground-state band have been deduced. The results establish a breaking of the normal trend of increasing first excited 2+ and 4+ level energies as a function of the decreasing neutron number as the N=50 major shell gap is approached for the neutron-deficient Xe isotopes. This unusual feature is suggested to be an effect of enhanced collectivity, possibly arising from isoscalar n-p interactions becoming increasingly important close to the N=Z line.

  • 25. Soderstrom, P. -A
    et al.
    Recchia, F.
    Nyberg, J.
    Gadea, A.
    Lenzi, S. M.
    Poves, A.
    Atac, A.
    Aydin, S.
    Bazzacco, D.
    Bednarczyk, P.
    Bellato, M.
    Birkenbach, B.
    Bortolato, D.
    Boston, A. J.
    Boston, H. C.
    Bruyneel, B.
    Bucurescu, D.
    Calore, E.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Charles, L.
    Chavas, J.
    Colosimo, S.
    Crespi, F. C. L.
    Cullen, D. M.
    de Angelis, G.
    Desesquelles, P.
    Dosme, N.
    Duchene, G.
    Eberth, J.
    Farnea, E.
    Filmer, F.
    Gorgen, A.
    Gottardo, A.
    Grebosz, J.
    Gulmini, M.
    Hess, H.
    Hughes, T. A.
    Jaworski, G.
    Jolie, J.
    Joshi, P.
    Judson, D. S.
    Jungclaus, A.
    Karkour, N.
    Karolak, M.
    Kempley, R. S.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Korten, W.
    Ljungvall, J.
    Lunardi, S.
    Maj, A.
    Maron, G.
    Meczynski, W.
    Menegazzo, R.
    Mengoni, D.
    Michelagnoli, C.
    Molini, P.
    Napoli, D. R.
    Nolan, P. J.
    Norman, M.
    Obertelli, A.
    Podolyak, Zs.
    Pullia, A.
    Quintana, B.
    Redon, N.
    Regan, P. H.
    Reiter, P.
    Robinson, A. P.
    Sahin, E.
    Simpson, J.
    Salsac, M. D.
    Smith, J. F.
    Stezowski, O.
    Theisen, Ch.
    Tonev, D.
    Unsworth, C.
    Ur, C. A.
    Valiente-Dobon, J. J.
    Wiens, A.
    High-spin structure in K-402012In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 86, no 5, p. 054320-Article in journal (Refereed)
    Abstract [en]

    High-spin states of K-40 have been populated in the fusion-evaporation reaction C-12(Si-30,np)K-40 and studied by means of gamma-ray spectroscopy techniques using one triple-cluster detector of the Advanced Gamma Tracking Array at the Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro. Several states with excitation energy up to 8 MeV and spin up to 10(-) have been discovered. These states are discussed in terms of J = 3 and T = 0 neutron-proton hole pairs. Shell-model calculations in a large model space have shown good agreement with the experimental data for most of the energy levels. The evolution of the structure of this nucleus is here studied as a function of excitation energy and angular momentum.

  • 26.
    Söderstrom, P. -A
    et al.
    Uppsala University, Department of Physics and Astronomy.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    et al,
    Interaction position resolution simulations and in-beam measurements of the AGATA HPGe detectors2011In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 638, no 1, p. 96-109Article in journal (Refereed)
    Abstract [en]

    The interaction position resolution of the segmented HPGe detectors of an AGATA triple cluster detector has been studied through Monte Carlo simulations and in an in-beam experiment. A new method based on measuring the energy resolution of Doppler-corrected gamma-ray spectra at two different target to detector distances is described. This gives the two-dimensional position resolution in the plane perpendicular to the direction of the emitted gamma-ray. The gamma-ray tracking was used to determine the full energy of the gamma-rays and the first interaction point, which is needed for the Doppler correction. Five different heavy-ion induced fusion-evaporation reactions and a reference reaction were selected for the simulations. The results of the simulations show that the method works very well and gives a systematic deviation of <1 mm in the FVVHM of the interaction position resolution for the gamma-ray energy range from 60 keV to 5 MeV. The method was tested with real data from an in-beam measurement using a (30)5i beam at 64 MeV on a thin C-12 target. Pulse-shape analysis of the digitized detector waveforms and gamma-ray tracking was performed to determine the position of the first interaction point, which was used for the Doppler corrections. Results of the dependency of the interaction position resolution on the gamma-ray energy and on the energy, axial location and type of the first interaction point, are presented. The FVVHM of the interaction position resolution varies roughly linearly as a function of gamma-ray energy from 8.5 mm at 250 key to 4 mm at 1.5 MeV, and has an approximately constant value of about 4 mm in the gamma-ray energy range from 1.5 to 4 MeV.

  • 27. Tashenov, S.
    et al.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Barday, R.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Enders, J.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Fritzsche, Y.
    Schässburger, Kai-Uwe
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Surzhykov, A.
    Yerokhin, V. A.
    Observation of the spin-orbit interaction in bremsstrahlung2013In: Physica scripta. T, ISSN 0281-1847, Vol. T156, p. 014071-Article in journal (Refereed)
    Abstract [en]

    The effects of the spin-orbit interaction are pronounced for an electron scattered in a Coulomb field of the nucleus. They cause the electron scattering plane to turn or precess as the electron moves. This precession is visible through linear polarization of bremsstrahlung. The first experiment to observe it is described in this contribution.

  • 28. Tashenov, S.
    et al.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Barday, R.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Enders, J.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Fritzsche, Yu
    Schässburger, Kai-Uwe
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Surzhykov, A.
    Yerokhin, V. A.
    Jakubassa-Amundsen, D.
    Bremsstrahlung polarization correlations and their application for polarimetry of electron beams2013In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 87, no 2, p. 022707-Article in journal (Refereed)
    Abstract [en]

    Linear polarization of hard x rays emitted in the process of atomic-field electron bremsstrahlung has been measured with a polarized electron beam. The correlation between the initial orientation of the electron spin and the angle of photon polarization has been systematically studied by means of Compton and Rayleigh polarimetry techniques applied to a segmented germanium detector. The results are in good agreement with those of fully relativistic calculations. The observed correlations are also explained classically and in a unique way manifest that due to the spin-orbit interaction the electron scattering trajectory is not confined to a single scattering plane. The developed photon polarimetry technique with a passive scatterer is very efficient and accurate and thus allows for additional applications. Bremsstrahlung polarization correlations lead to an alternative method of polarimetry of electron beams. Such a method is sensitive to all three components of the electron spin. It can be applied in a broad range of the electron beam energies from approximate to 100 keV up to a few tens of MeV. The results of a measurement at 100 keV are shown. The optimum scheme for electron polarimetry is analyzed and the relevant theoretical predictions are presented.

  • 29. Tashenov, S.
    et al.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Barday, R.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Enders, J.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics.
    Fritzsche, Yu.
    Surzhykov, A.
    Yerokhin, V. A.
    Jakubassa-Amundsen, D.
    Electron polarimetry with bremsstrahlung2014In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 488, no SECTION 1, article id 012057Article in journal (Refereed)
    Abstract [en]

    Due to the spin-orbit interaction, the electron scattering from the nucleus is sensitive to the spin orientation of that electron. This is used for polarimetry of electron beams in the Mott method. The spin-orbit interaction was also observed in bremsstrahlung. In this article we analyze its potential for polarimetry as an alternative to the Mott method. It can simultaneously measure all three electron polarization components. It should work in the energy range of 50 keV up to several MeV and can be applied at beam intensities higher than 100 nA. It needs a thin heavy element target, two or four x-ray detectors and one x-ray linear polarimeter.

  • 30. Tashenov, S.
    et al.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Khaplanov, Anton
    Schässburger, Kai-Uwe
    Barday, R.
    Enders, J.
    Poltoratska, Y.
    Surzhykov, A.
    Yerokhin, V.
    Jakubassa-Amundsen, D.
    Bremsstrahlung polarization correlations and their application for polarimetry of electron beams2014In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 488, no SECTION 4, article id 042021Article in journal (Refereed)
    Abstract [en]

    The correlation between electron spin and photon linear polarization in atomic-field bremsstrahlung was measured with a polarized electron beam. The angle of photon polarization and the photon emission intensity were found to be correlated with the spin orientation. These effects are interpreted in terms of spin-orbit interaction. They lead to a new technique of electron beam polarimetry.

  • 31. Tashenov, Stanislav
    et al.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Barday, R.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Enders, J.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Poltoratska, Yu.
    Schassburger, Kai-Uwe
    Surzhykov, A.
    Measurement of the Correlation between Electron Spin and Photon Linear Polarization in Atomic-Field Bremsstrahlung2011In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 107, no 17, p. 173201-Article in journal (Refereed)
    Abstract [en]

    Atomic-field bremsstrahlung has been studied with a longitudinally polarized electron beam. The correlation between the initial orientation of the electron spin and the angle of photon polarization has been measured at the photon high energy tip region. In the time reversal this corresponds to a so-far unobserved phenomenon of production of longitudinally polarized electrons by photoionization of unpolarized atoms with linearly polarized photons. The results confirm the fully relativistic calculations for radiative recombination and suggest a new method for electron beam polarimetry.

  • 32.
    Tashenov, Stanislav
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Gamma-ray tracking and background suppression in the planned germanium array of DESPEC: A comparative analysis2009In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 604, no 1-2, p. 64-66Article in journal (Refereed)
    Abstract [en]

    A new high efficiency gamma-ray spectrometer is being designed for the DESPEC project at FAIR. It should accomplish all types of decay studies with implanted radioactive ion beams. The gamma-ray tracking and imaging capabilities of the array will be its essential property allowing low background detection of the rare decay events. For this purpose two types of germanium detectors are considered, i.e. segmented planar and coaxial detectors. Several final array configurations based on these detectors, differently segmented, are evaluated and compared in this paper.

  • 33.
    Tashenov, Stanislav
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Schässburger, Kai-Uwe
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hard X-ray polarimetry by means of Rayleigh scattering2009In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 600, no 3, p. 599-603Article in journal (Refereed)
    Abstract [en]

    A new linear polarimetry technique based on Rayleigh scattering is introduced. Its properties are compared to the Compton technique. Experimental verification was realized using a 5 x 5 segmented planar HPGe pixel detector. In the proof-of-principle experiment a measurement of Rayleigh scattering off lead atoms was performed for linearly polarized; approximate to 53.3 keV photons at two scattering angles.

1 - 33 of 33
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