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8. Observation of the proton emitter 57116La59

Author

Zhang, Wei, Cederwall, Bo, Aktas, Özge, Liu, Xiaoyu, Ertoprak, Aysegül, Nyberg, Ayse, Auranen, Kalle, Alayed, Betool, Badran, Hussam, Boston, Helen, Doncel, Maria, Forsberg, Ulrika, Grahn, Tuomas, Greenlees, Paul T., Guo, Song, Heery, Jacob, Hilton, Joshua, Jenkins, David, Julin, Rauno, Juutinen, Sakari, Luoma, Minna, Neuvonen, Olavi, Ojala, Joonas, Page, Robert D., Pakarinen, Janne, Partanen, Jari, Paul, Edward S., Petrache, Costel, Rahkila, Panu, Ruotsalainen, Panu, Sandzelius, Mikael, Sarén, Jan, Szwec, Stuart, Tann, Holly, Uusitalo, Juha, and Wadsworth, Robert

Published
2022
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9. Isomeric Lifetime Measurement in the Neutron-rich 189Ta

Author

Alhomaidhi Sultan, Sahin Elif, Werner Volker, Jolie Jan, Regan Patrick, Pietralla Norbert, Gerl Jürgen, Górska Magdalena, Benzoni Giovanna, Mistry Andrew K., Hubbard Nicolas, Aggez Guler, Albers Helena M., Arici Tugba, Armstrong Michael, Banerjee Akashrup, Das Biswarup, Davinson Thomas, Hall Oscar, Kojouharov Ivan, Koseoglou Pavlos, Mikolajczuk Michal, Podolyák Zsolt, Polettini Marta, Rudigier Matthias, Schaffner Henning, Wollersheim Hans-Jürgen, Yaneva Aleksandrina, Boutachkov Plamen, Dickel Timo, Haettner Emma, Heggen Henning, Hornung Christine, Knöbel Ronja, Kostyleva Daria, Kurz Nikolaus, Kuzminchuk Natalia, Mukha Ivan, Pietri Stephane, Plaß Wolfgang, Scheidenberger Christoph, Tanaka Yoshiki, Weick Helmut, Ahmed Usama, Aktas Özge, Algora Alejandro, Appleton Corrigan, Blazhev Andrey, Bruce Alison, Cederwall Bo, Chishti Muhammad M. R., Cortes Martha L., Crespi Fabio, Dobon Jose J., Doncel Maria, Ertoprak Aysegül, Esmaylzadeh Arwin, Expósito Marcos L., Fraile Luis M., García Jaime B., Gottardo Andrea, Ha Jeongsu, Jazrawi Shaheen, John Philipp R., Jones Calum, Karayonchev Vasil, Kern Ralph, Knafla Lukas, Kosir Gregor, Lozeva Radomira, Mengoni Daniele, Mertzimekis Theo J., Million Bénédicte, Morales Anabel, Murias Javier R., Orrigo Sonja E. A., Pellumaj Julgen, Pelonis Stefanos, Petrović Jana, Pigliapoco Sara, Quintana Begoña, Recchia Francesco, Rezynkina Kseniia, Sexton Lewis, Singh Nara, Söderström Pär-Anders, Sood Arshiya, Vasileiou Polytimos, Vesic Jelena, Wiederhold Johannes, zhang guangxin, Zidarova Radostina, and Zyriliou Aikaterini

Subjects
Physics, QC1-999
Abstract

Isomeric states of the neutron-rich isotope 18973Ta116 were populated via fragmentation of a primary beam of 208Pb ions at 1 GeV/u impinging on a 9Be target at GSI, Darmstadt, Germany. The isotopes of interest were separated, identified and delivered to the DESPEC setup. Two isomers were deduced in 189Ta116 and their lifetimes were measured based on the γ-ray time distributions.

Published
2023
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12. Observation of the proton emitter $${}_{\,57}^{116}$$La59

Author

Zhang, Wei, primary, Cederwall, Bo, additional, Aktas, Özge, additional, Liu, Xiaoyu, additional, Ertoprak, Aysegül, additional, Nyberg, Ayse, additional, Auranen, Kalle, additional, Alayed, Betool, additional, Badran, Hussam, additional, Boston, Helen, additional, Doncel, Maria, additional, Forsberg, Ulrika, additional, Grahn, Tuomas, additional, Greenlees, Paul T., additional, Guo, Song, additional, Heery, Jacob, additional, Hilton, Joshua, additional, Jenkins, David, additional, Julin, Rauno, additional, Juutinen, Sakari, additional, Luoma, Minna, additional, Neuvonen, Olavi, additional, Ojala, Joonas, additional, Page, Robert D., additional, Pakarinen, Janne, additional, Partanen, Jari, additional, Paul, Edward S., additional, Petrache, Costel, additional, Rahkila, Panu, additional, Ruotsalainen, Panu, additional, Sandzelius, Mikael, additional, Sarén, Jan, additional, Szwec, Stuart, additional, Tann, Holly, additional, Uusitalo, Juha, additional, and Wadsworth, Robert, additional

Published
2022
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13. Decay studies in the A∼225 Po-Fr region from the DESPEC campaign at GSI in 2021

Author

Polettini, M., Pellumaj, J., Benzoni, G., Zhang, G., Mengoni, D., Perez Vidal, R. M., Genna, D., Bracco, A., Aggez, G., Al Aqueel, M., Alayed, B., Albers, H. M., Algora, A., Alhomaidhi, S., Appleton, C., Arici, T., Armstrong, M., Arnswald, K., Balogh, M., Banerjee, A., Blazhev, A., Bottoni, S., Boutachkov, P., Bruce, A., Bruno, C., Camera, F., Cederwall, B., Chishti, M. M. R., Cox, D. M., Crespi, F. C. L., Das, B., Davinson, T., De Angelis, G., Dickel, T., Doncel, Maria, Donthi, R., Ertoprak, A., Escudeiro, R., Esmaylzadeh, A., Fraile, L. M., Gaffney, L., Gamba, E. R., Gerl, J., Gottardo, A., Ha, J., Haettner, E., Hall, O., Heggen, H., Hrabar, Y., Hubbard, N., Jazrawi, S., John, P. R., Jolie, J., Jones, C., Joss, D., Judson, D., Kahl, D., Karayonchev, V., Kazantseva, E., Kern, R., Knafla, L., Kojouharov, I., Korgul, A., Korten, W., Koseoglou, P., Kosir, G., Kostyleva, D., Kurtukian-Nieto, T., Kurz, N., Kuzminchuk, N., Labiche, M., Lenzi, S., Leoni, S., Lozeva, R., Mertzimekis, T. J., Mikolajczuk, M., Million, B., Mistry, A. K., Morales, A., Mukha, I., Murias, J. R., Napoli, D., NaraSingh, B. S., O'Donnell, D., Orrigo, S. E. A., Page, R., Pelonis, S., Petrovic, J., Pietralla, N., Pietri, S., Pigliapoco, S., Podolyak, Zs., Porzio, C., Quintana Arnes, B., Recchia, F., Regan, P. H., Reiter, P., Rezynkina, K., Roy, P., Rudigier, M., Ruotsalainen, P., Sahin, E., Sarmiento, L. G., Satrazani, M.-M., Schaffner, H., Scheidenberger, C., Sexton, L., Sharma, A., Smallcombe, J., Sood, A., Vasileiou, P., Vesic, J., Vilhena, J., Waring, L., Weick, H., Werner, V., Wiederhold, J., Wieland, O., Wimmer, K., Wollersheim, H. J., Woods, P., Yaneva, A., Zanon, I., Zhao, J., Zidarova, R., Ziliani, S., Zimba, G., Zyriliou, A., Polettini, M., Pellumaj, J., Benzoni, G., Zhang, G., Mengoni, D., Perez Vidal, R. M., Genna, D., Bracco, A., Aggez, G., Al Aqueel, M., Alayed, B., Albers, H. M., Algora, A., Alhomaidhi, S., Appleton, C., Arici, T., Armstrong, M., Arnswald, K., Balogh, M., Banerjee, A., Blazhev, A., Bottoni, S., Boutachkov, P., Bruce, A., Bruno, C., Camera, F., Cederwall, B., Chishti, M. M. R., Cox, D. M., Crespi, F. C. L., Das, B., Davinson, T., De Angelis, G., Dickel, T., Doncel, Maria, Donthi, R., Ertoprak, A., Escudeiro, R., Esmaylzadeh, A., Fraile, L. M., Gaffney, L., Gamba, E. R., Gerl, J., Gottardo, A., Ha, J., Haettner, E., Hall, O., Heggen, H., Hrabar, Y., Hubbard, N., Jazrawi, S., John, P. R., Jolie, J., Jones, C., Joss, D., Judson, D., Kahl, D., Karayonchev, V., Kazantseva, E., Kern, R., Knafla, L., Kojouharov, I., Korgul, A., Korten, W., Koseoglou, P., Kosir, G., Kostyleva, D., Kurtukian-Nieto, T., Kurz, N., Kuzminchuk, N., Labiche, M., Lenzi, S., Leoni, S., Lozeva, R., Mertzimekis, T. J., Mikolajczuk, M., Million, B., Mistry, A. K., Morales, A., Mukha, I., Murias, J. R., Napoli, D., NaraSingh, B. S., O'Donnell, D., Orrigo, S. E. A., Page, R., Pelonis, S., Petrovic, J., Pietralla, N., Pietri, S., Pigliapoco, S., Podolyak, Zs., Porzio, C., Quintana Arnes, B., Recchia, F., Regan, P. H., Reiter, P., Rezynkina, K., Roy, P., Rudigier, M., Ruotsalainen, P., Sahin, E., Sarmiento, L. G., Satrazani, M.-M., Schaffner, H., Scheidenberger, C., Sexton, L., Sharma, A., Smallcombe, J., Sood, A., Vasileiou, P., Vesic, J., Vilhena, J., Waring, L., Weick, H., Werner, V., Wiederhold, J., Wieland, O., Wimmer, K., Wollersheim, H. J., Woods, P., Yaneva, A., Zanon, I., Zhao, J., Zidarova, R., Ziliani, S., Zimba, G., and Zyriliou, A.

Abstract

The HISPEC-DESPEC collaboration aims at investigating the structure of exotic nuclei formed in fragmentation reactions with decay spectroscopy measurements, as part of the FAIR Phase-0 campaign at GSI. This paper reports on first results of an experiment performed in spring 2021, with a focus on beta-decaystudies in the Po-Fr nuclei in the 220 < A <230 island of octupole deformation exploiting the DESPEC setup. Ion-beta correlations and fast-timing techniques are being employed, giving an insight into this difficult-to-reach region.

Published
2022
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14. First observation of the proton emitter 116La: Evidence for strong neutron-proton pairing from proton separation energies and emission probabilities

Author

Zhang, Wei, primary, Cederwall, Bo, additional, AKTAS, Ozge, additional, Liu, Xiaoyu, additional, Ertoprak, Aysegül, additional, Nyberg, Ayse, additional, Auranen, Kalle, additional, Alayed, Betool, additional, Badran, Hussam, additional, Boston, Helen, additional, Doncel, Maria, additional, Forsberg, Ulrika, additional, Grahn, Tuomas, additional, Greenlees, Paul, additional, GUO, Song, additional, Heery, Jacob, additional, Hilton, Joshua, additional, Jenkins, David, additional, Julin, Rauno, additional, Juutinen, Sakari, additional, Luoma, Minna, additional, Neuvonen, Olavi, additional, Ojala, Joonas, additional, Page, Robert, additional, Pakarinen, Janne, additional, Paul, Edward, additional, Petrache, Costel, additional, Rahkila, Panu, additional, Ruotsalainen, Panu, additional, Sandzelius, Mikael, additional, Sarén, Jan, additional, Szwec, Stuart, additional, Tann, Holly, additional, Uusitalo, Juha, additional, and Wadsworth, Robert, additional

Published
2022
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15. Observation of the proton emitter 116,57La59

Author

Zhang, Wei, Cederwall, Bo, Aktas, Özge, Liu, Xiaoyu, Ertoprak, Aysegül, Nyberg, Ayse, Auranen, Kalle, Alayed, Betool, Badran, Hussam, Boston, Helen, Doncel, Maria, Forsberg, Ulrika, Grahn, Tuomas, Greenlees, Paul T., Guo, Song, Heery, Jacob, Hilton, Joshua, Jenkins, David, Julin, Rauno, Juutinen, Sakari, Luoma, Minna, Neuvonen, Olavi, Ojala, Joonas, Page, Robert D., Pakarinen, Janne, Partanen, Jari, Paul, Edward S., Petrache, Costel, Rahkila, Panu, Ruotsalainen, Panu, Sandzelius, Mikael, Sarén, Jan, Szwec, Stuart, Tann, Holly, Uusitalo, Juha, and Wadsworth, Robert

Subjects
isotoopit, massaspektrometria, protonit, ydinfysiikka, emissio (fysiikka)
Abstract

The quantum tunneling and emission of a single constituent nucleon provide a beautifully simple and unique window into the complex properties of atomic nuclei at the extreme edge of nuclear existence. In particular, for odd-odd proton emitting nuclides, the associated decay energy and partial half-life can be used to probe the correlations between the valence neutrons and protons which have been theoretically predicted to favour a new type of nuclear superfluidity, isoscalar neutron-proton pairing, for which the experimental “smoking gun" remains elusive. In the present work, proton emission from the lanthanum isotope 11657La59, 23 neutrons away from the only stable isotope 13957La82, is reported. 116La nuclei were synthesised in the fusion-evaporation reaction 58Ni(64Zn, p5n)116La and identified via their proton radioactivity using the mass spectrometer MARA (Mass Analysing Recoil Apparatus) and the silicon detectors placed at its focal plane. Comparisons of the measured proton energy (Ep = 718 ± 9 keV) and half-life (T1/2 = 50 ± 22 ms) with values calculated using the Universal Decay Law approach indicate that the proton is emitted with an orbital angular momentum l = 2 and that its emission probability is enhanced relative to its closest, less exotic, odd-even lanthanum isotope (11757La60) while the proton-emission Q-value is lower. We propose this to be a possible signature for the presence of strong neutron-proton pair correlations in this exotic, neutron deficient system. The observations of γ decays from isomeric states in 116La and 117La are also reported. peerReviewed

Published
2022

16. Observation of the proton emitter 57116La59.

Author

Zhang, Wei, Cederwall, Bo, Aktas, Özge, Liu, Xiaoyu, Ertoprak, Aysegül, Nyberg, Ayse, Auranen, Kalle, Alayed, Betool, Badran, Hussam, Boston, Helen, Doncel, Maria, Forsberg, Ulrika, Grahn, Tuomas, Greenlees, Paul T., Guo, Song, Heery, Jacob, Hilton, Joshua, Jenkins, David, Julin, Rauno, and Juutinen, Sakari

Subjects
NUCLIDES, NUCLEAR physics, ATOMIC nucleus, QUANTUM tunneling, NEUTRON emission, HEAVY ion fusion reactions, PROTONS
Abstract

The quantum tunneling and emission of a single constituent nucleon provide a beautifully simple and unique window into the complex properties of atomic nuclei at the extreme edge of nuclear existence. In particular, for odd-odd proton emitting nuclides, the associated decay energy and partial half-life can be used to probe the correlations between the valence neutrons and protons which have been theoretically predicted to favour a new type of nuclear superfluidity, isoscalar neutron-proton pairing, for which the experimental "smoking gun" remains elusive. In the present work, proton emission from the lanthanum isotope 57 116 La59, 23 neutrons away from the only stable isotope 57 139 La82, is reported. 116La nuclei were synthesised in the fusion-evaporation reaction 58Ni(64Zn, p5n)116La and identified via their proton radioactivity using the mass spectrometer MARA (Mass Analysing Recoil Apparatus) and the silicon detectors placed at its focal plane. Comparisons of the measured proton energy (Ep = 718 ± 9 keV) and half-life (T1/2 = 50 ± 22 ms) with values calculated using the Universal Decay Law approach indicate that the proton is emitted with an orbital angular momentum l = 2 and that its emission probability is enhanced relative to its closest, less exotic, odd-even lanthanum isotope ( 57 117 La60) while the proton-emission Q-value is lower. We propose this to be a possible signature for the presence of strong neutron-proton pair correlations in this exotic, neutron deficient system. The observations of γ decays from isomeric states in 116La and 117La are also reported. Neutron-proton pairing is a topic of continuous interest in nuclear physics and open questions remain. The authors experimentally observe direct proton decay from the ground state of odd-odd 116La, providing support for the presence of strong neutron-proton pair correlations in this exotic, neutron deficient system. [ABSTRACT FROM AUTHOR]

Published
2022
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17. PostMinQuake: Potential Learnings of induced seismicity during post-mining in European coal regions

Author

Doncel , Maria Paloma Primo, Goerke-Mallet , Peter, Möllerherm, Stefan, and Rudolph, Tobias

Abstract

The task of this European research project (PostMinQuake) is to identify mechanisms, relevant parameters and dependencies causing post-mining seismicity for several European coal regions. When closing an underground coalmine, the mine water raises by stopping mine water pumping, which can lead to micro seismic events due to the final change of the geomechanical stress-regime. The consortium partners (FZN-THGA, GFZ, BRGM, INERIS, CMI, SUT, SRK, IGN, Green Gas, DIAMO) will collect and analyse information from the coal basins Gardanne (France) and Upper Silesia (Czech Republic and Poland). In Germany, we will focus in the Ruhr Basin and Ibbenbüren (North-West Germany), which are places with centuries of hard coal mining history and where mining ceased in 2018. In order to detect the processes that cause micro-seismicity, we are gathering information in the basins regarding geology; mining methods and monitoring protocols; and post-mining situation and seismicity. This information will be analysed to identify similar approaches to develop a synthesis of good practices, compulsory and desired improvements, as well as an post-mining seismicity map for post-mining seismicity diagnosis. We also aim to develop a Ground Motion Prediction Equation, and the elaboration of criteria of hazard rating. The final guideline could help the mining industry and decision-making bodies to manage the risks of post-mining micro seismicity, also of interest in old petroleum reservoirs when used to storage H2 or even for geothermal energy. Acknowledgements: The Research Fund for Coal and Steel funds the PostMinQuake project under the grant agreement No 899192.

Published
2021
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18. Single-particle and collective excitations in the transitional nucleus Os-166

Author

Stolze, S., Grahn, T., Andgren, Karin, Doncel, Maria, Uusitalo, J., Stolze, S., Grahn, T., Andgren, Karin, Doncel, Maria, and Uusitalo, J.

Abstract

The mean lifetimes of the lowest energy 2(+), 8(+) and 9(-) states in Os-166 have been measured using the recoil distance Doppler-shift method in conjunction with a selective recoil-decay tagging technique. These measurements extend studies into the most neutron-deficient mass region accessible to current experimental methods. The B(E2; 2(+) -> 0(+)) = 7(2) W.u. extracted from these measurements is markedly lower than those observed in the heavier even-mass Os isotopes. The 8(+) and 9(-) states yield reduced transition probabilities that are consistent with single-particle transitions. While these values may indicate a departure from collective structure, the level scheme and the underlying nuclear configurations can also be interpreted in terms of a simple collective picture. This contrasting behaviour suggests an intriguing dichotomy in the description of heavy transitional nuclei., QC 20211101

Published
2021
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21. Evidence for octupole collectivity in 172Pt

Author

Ertoprak, Aysegul, Cederwall, Bo, Qi, Chong, Aktas, Özge, Doncel, Maria, Hadinia, Baharak, Liotta, Roberto, Sandzelius, M., Scholey, C., Andgren, Karin, Bäck, Torbjörn, Badran, H., Braunroth, T., Calverley, T., Cox, D. M., Cullen, D. M., Fang, Y. D., Ganioglu, E., Giles, M., Gomez-Hornillos, M.B., Grahn, T., Greenlees, P. T., Hilton, J., Hodge, D., Ideguchi, E., Jakobsson, U., Johnson, Arne, Jones, P.M., Julin, R., Juutinen, S., Ketelhut, S., Khaplanov, Anton, Kumar Raju, M., Leino, M., Li, H., Liu, H., Matta, S., Modamio, V., Nara Singh, B. S., Niikura, M., Nyman, M., Özgur, I., Page, R. D., Pakarinen, J., Papadakis, P., Partanen, J., Paul, E. S., Petrache, C. M., Peura, P., Rahkila, P., Ruotsalainen, P., Saren, J., Sorri, J., Stolze, S., Subramaniam, P., Taylor, M. J., Uusitalo, J., Valiente-Dobon, J. J., Wyss, Ramon Alexander, Ertoprak, Aysegul, Cederwall, Bo, Qi, Chong, Aktas, Özge, Doncel, Maria, Hadinia, Baharak, Liotta, Roberto, Sandzelius, M., Scholey, C., Andgren, Karin, Bäck, Torbjörn, Badran, H., Braunroth, T., Calverley, T., Cox, D. M., Cullen, D. M., Fang, Y. D., Ganioglu, E., Giles, M., Gomez-Hornillos, M.B., Grahn, T., Greenlees, P. T., Hilton, J., Hodge, D., Ideguchi, E., Jakobsson, U., Johnson, Arne, Jones, P.M., Julin, R., Juutinen, S., Ketelhut, S., Khaplanov, Anton, Kumar Raju, M., Leino, M., Li, H., Liu, H., Matta, S., Modamio, V., Nara Singh, B. S., Niikura, M., Nyman, M., Özgur, I., Page, R. D., Pakarinen, J., Papadakis, P., Partanen, J., Paul, E. S., Petrache, C. M., Peura, P., Rahkila, P., Ruotsalainen, P., Saren, J., Sorri, J., Stolze, S., Subramaniam, P., Taylor, M. J., Uusitalo, J., Valiente-Dobon, J. J., and Wyss, Ramon Alexander

Abstract

Excited states in the extremely neutron-deficient nucleus 172Pt were populated via 96Ru(78Kr,2p) and 92Mo(83Kr,3n) reactions. The level scheme has been extended up to an excitation energy of ~ 5 MeV and tentative spin-parity assignments up to Iπ = 18+. Linear polarization and angular distribution measurements were used to determine the electromagnetic E1 character of the dipole transitions connecting the positive-parity ground-state band with an excited side-band, firmly establishing it as a negative-parity band. The lowest member of this negative-parity structure was firmly assigned spin-parity 3-. In addition, we observed an E3 transition from this 3- state to the ground state, providing direct evidence for octupole collectivity in 172Pt. Large-scale shell model (LSSM) and total Routhian surface (TRS) calculations have been performed, supporting the interpretation of the 3- state as a collective octupole-vibrational state., QC 20200427

Published
2020
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22. Lifetimes of core-excited states in semi-magic Rh-95

Author

Ertoprak, A., Qi, Chong, Cederwall, Bo, Doncel, Maria, Jakobsson, Ulrika, Nyberg, Ayse, Bäck, Torbjörn, Ghazi Moradi, Farnaz, Li, Haipeng, Xiao, Z. G., et al., Ertoprak, A., Qi, Chong, Cederwall, Bo, Doncel, Maria, Jakobsson, Ulrika, Nyberg, Ayse, Bäck, Torbjörn, Ghazi Moradi, Farnaz, Li, Haipeng, Xiao, Z. G., and et al.

Abstract

Lifetimes of negative-parity states have been determined in the neutron deficient semi-magic (N = 50) nucleus Rh-95. The fusion-evaporation reaction Ni-58(Ca-40, 3p) was used to populate high-spin states in Rh-95 at the Grand Accelerateur National d'Ions Lourds (GANIL) accelerator facility. The results were obtained using the Doppler Shift Attenuation Method (DSAM) based on the Doppler broadened line shapes produced during the slowing down process of the residual nuclei in a thick 6 mg/cm(2) metallic target. B(M1) and B(E2) reduced transition strengths are compared with predictions from large-scale shell-model calculations. state-of-the-art theory. Remarkably, the structural features up to moderate angular momentum of nuclei immediately below the N = Z = 50 shell closures can be described with high accuracy in a very simple way by shell-model calculations including only the g(9/2) and p(1/2) subshells. Of special interest is the neutron-proton pair coupling scheme which is expected to appear in the heaviest N=Z nuclei [1,2] and the seniority structure of the N = 50 isotones [3-7]. However, multiple core-excited states have been observed in the semi-magic nuclei of the Sn-100 region [8-10]. The theoretical study of those states is a challenging task, which requires a significantly larger model space for their interpretation. Transition probabilities between nuclear states provide important constraints for theoretical modelling of the structure of the nuclei of interest. Our previous lifetime study of the semimagic (N = 50) nucleus Ru-94 [ 11,12] provided information on the electromagnetic decay properties of neutron-core excited states. We now address lifetime measurements in its closest, more neutron deficient, isotone Rh-95 using the same DSAM technique. The experimental results have been interpreted within the framework of large-scale shell-model (LSSM) calculations., QC 20201217

Published
2020
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23. M1 and E2 transition rates from core-excited states in semi-magic Ru-94

Author

Ertoprak, Aysegul, Cederwall, Bo, Qi, Chong, Doncel, Maria, Jakobsson, U., Nyako, B. M., Jaworski, G., Davies, P., de France, G., Kuti, I., Napoli, D. R., Wadsworth, R., Ghugre, S. S., Raut, R., Akkus, B., Al Azri, H., Algora, A., de Angelis, G., Atac Nyberg, Ayse, Bäck, Torbjörn, Boso, A., Clement, E., Debenham, D. M., Dombradi, Zs., Erturk, S., Gadea, A., Moradi, F. Ghazi, Gottardo, A., Huyuk, T., Ideguchi, E., Li, H., Michelagnoli, C., Modamio, V., Nyberg, J., Palacz, M., Petrache, C. M., Recchia, F., Sandzelius, M., Siciliano, M., Timar, J., Valiente-Dobon, J. J., Xiao, Z. G., Ertoprak, Aysegul, Cederwall, Bo, Qi, Chong, Doncel, Maria, Jakobsson, U., Nyako, B. M., Jaworski, G., Davies, P., de France, G., Kuti, I., Napoli, D. R., Wadsworth, R., Ghugre, S. S., Raut, R., Akkus, B., Al Azri, H., Algora, A., de Angelis, G., Atac Nyberg, Ayse, Bäck, Torbjörn, Boso, A., Clement, E., Debenham, D. M., Dombradi, Zs., Erturk, S., Gadea, A., Moradi, F. Ghazi, Gottardo, A., Huyuk, T., Ideguchi, E., Li, H., Michelagnoli, C., Modamio, V., Nyberg, J., Palacz, M., Petrache, C. M., Recchia, F., Sandzelius, M., Siciliano, M., Timar, J., Valiente-Dobon, J. J., and Xiao, Z. G.

Abstract

Lifetimes of high-spin states have been measured in the semi-magic (N = 50) nucleus Ru-94. Excited states in Ru-94 were populated in the Ni-58(Ca-40, 4p)Ru-94* fusion-evaporation reaction at the Grand Accelerateur National d'Ions Lourds (GANIL) accelerator complex. DSAM lifetime analysis was performed on the Doppler broadened line shapes in energy spectra obtained from gamma-rays emitted while the residual nuclei were slowing down in a thick 6 mg/cm(2) metallic Ni-58 target. In total eight excited-state lifetimes in the angular momentum range I = (13-20)h have been measured, five of which were determined for the first time. The corresponding B(M1) and B(E2) reduced transition strengths are discussed within the framework of large-scale shell model calculations to study the contribution of different particle-hole configurations, in particular for analyzing contributions from core-excited configurations., QC 20180917

Published
2018
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24. Lifetime measurements of excited states in W-162 and W-164 and the evolution of collectivity in rare-earth nuclei

Author

Doncel, Maria, Cederwall, Bo, Qi, Chong, Li, Hongjie J., Jakobsson, Ulrika, Auranen, K., Boenig, S., Drummond, M. C., Grahn, T., Greenlees, P. T., Herzan, A., Joss, D. T., Julin, R., Juutinen, S., Konki, J., Kroell, T., Leino, M., McPeake, C., O'Donnell, D., Page, R. D., Pakarinen, J., Partanen, J., Peura, P., Rahkila, P., Ruotsalainen, P., Sandzelius, M., Saren, J., Saygi, B., Scholey, C., Sorri, J., Stolze, S., Taylor, M. J., Thornthwaite, A., Uusitalo, J., and Ege Üniversitesi

Subjects
Physical Sciences, Fysik
Abstract

WOS: 000400140500006, Lifetimes of the first excited 2(+) states in the extremely neutron- deficient W-162 and W-164 nuclei have been measured using the recoil distance Doppler shift technique. Experimental B(E2) data for the isotopic chains of hafnium, tungsten, and osmium, from the midshell region near the beta-stability line towards the N = 82 closed shell and the most neutron-deficient nuclides, are compared with predictions of nuclear deformations and 2(1)(+) -> 0(g.s)(.+) reduced transition strengths from different classes of state-of-the-art theoretical model calculations. The results reveal striking differences and deficiencies in the predictive power of current nuclear structure models., Swedish Research CouncilSwedish Research Council [621-2014-5558]; United Kingdom Science and Technology Facilities Council (STFC)Science & Technology Facilities Council (STFC)Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT)Japan Society for the Promotion of Science; EU 7th Framework Programme, Integrating Activities Transnational Access [262010 ENSAR]; Academy of Finland under the Finnish Centre of Excellence Programme (Nuclear and Accelerator Based Physics Programme at JYFL), This work was supported by the Swedish Research Council under Grant No. 621-2014-5558, the United Kingdom Science and Technology Facilities Council (STFC), the EU 7th Framework Programme, Integrating Activities Transnational Access, Project No. 262010 ENSAR, and the Academy of Finland under the Finnish Centre of Excellence Programme (Nuclear and Accelerator Based Physics Programme at JYFL). The authors acknowledge the support of the GAMMAPOOL for the JUROGAM detectors.

Published
2017

26. LIFETIME MEASUREMENTS WITH THE DOPPLER SHIFT ATTENUATION METHOD USING A THICK HOMOGENEOUS PRODUCTION TARGET - VERIFICATION OF THE METHOD

Author

Ertoprak, Aysegul, Cederwall, Bo, Jakobsson, Ulrika, Nyako, B. M., Nyberg, J., Davies, P., Doncel, Maria, De France, G., Kuti, I., Napoli, D. R., Wadsworth, R., Ghugre, S. S., Raut, R., Akkus, B., Al-Azri, H., Algora, A., de Angelis, G., Atac, A., Bäck, Torbjörn, Boso, A., Clement, E., Debenham, D. M., Dombradi, Zs., Erturk, S., Gadea, A., Ghazi Moradi, Farnaz, Gottardo, A., Huyuk, T., Ideguchi, E., Jaworski, G., Li, H., Michelagnoli, C., Modamio, V., Palacz, M., Petrache, C. M., Recchia, F., Sandzelius, M., Siciliano, M., Timar, J., Valiente-Dobon, J. J., Xiao, Z. G., Ertoprak, Aysegul, Cederwall, Bo, Jakobsson, Ulrika, Nyako, B. M., Nyberg, J., Davies, P., Doncel, Maria, De France, G., Kuti, I., Napoli, D. R., Wadsworth, R., Ghugre, S. S., Raut, R., Akkus, B., Al-Azri, H., Algora, A., de Angelis, G., Atac, A., Bäck, Torbjörn, Boso, A., Clement, E., Debenham, D. M., Dombradi, Zs., Erturk, S., Gadea, A., Ghazi Moradi, Farnaz, Gottardo, A., Huyuk, T., Ideguchi, E., Jaworski, G., Li, H., Michelagnoli, C., Modamio, V., Palacz, M., Petrache, C. M., Recchia, F., Sandzelius, M., Siciliano, M., Timar, J., Valiente-Dobon, J. J., and Xiao, Z. G.

Abstract

Doppler Shift Attenuation Method (DSAM) analysis of excited-state lifetimes normally employs thin production targets mounted on a thick stopper foil ("backing") serving to slow down and stop the recoiling nuclei of interest in a well-defined manner. Use of a thick, homogeneous production target leads to a more complex analysis as it results in a substantial decrease in the energy of the incident projectile which traverses the target with an associated change in the production cross section of the residues as a function of penetration depth. Here, a DSAM lifetime analysis using a thick homogeneous target has been verified using the Doppler broadened lineshapes of gamma rays following the decay of highly excited states in the semi-magic (N = 50) nucleus Ru-94. Lifetimes of excited states in the Ru-94 nucleus have been obtained using a modified version of the LINESHAPE package from the Doppler broadened lineshapes resulting from the emission of the gamma rays, while the residual nuclei were slowing down in the thick (6 mg/cm(2)) metallic Ni-58 target. The results have been validated by comparison with a previous measurement using a different (RDDS) technique., QC 20170508

Published
2017
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27. ISOSPIN SYMMETRY BREAKING IN MIRROR NUCLEI Mg-23-Na-23

Author

Boso, A., Lenzi, S. M., Recchia, F., Bonnard, J., Aydin, S., Bentley, M. A., Cederwall, Bo, Clement, E., De France, G., Di Nitto, A., Dijon, A., Doncel, Maria, Ghazi Moradi, Farnaz, Gottardo, A., Henry, T., Huyuk, T., Jaworski, G., John, P. R., Juhasz, K., Kuti, I., Melon, B., Mengoni, D., Michelagnoli, C., Modamio, V., Napoli, D. R., Nyako, B. M., Nyberg, J., Palacz, M., Valiente-Dobon, J. J., Boso, A., Lenzi, S. M., Recchia, F., Bonnard, J., Aydin, S., Bentley, M. A., Cederwall, Bo, Clement, E., De France, G., Di Nitto, A., Dijon, A., Doncel, Maria, Ghazi Moradi, Farnaz, Gottardo, A., Henry, T., Huyuk, T., Jaworski, G., John, P. R., Juhasz, K., Kuti, I., Melon, B., Mengoni, D., Michelagnoli, C., Modamio, V., Napoli, D. R., Nyako, B. M., Nyberg, J., Palacz, M., and Valiente-Dobon, J. J.

Abstract

Mirror energy differences (MED) are a direct consequence of isospin symmetry breaking. Moreover, the study of MED has proved to give valuable information of several nuclear structure properties. We present the results of an experiment performed in GANIL to study the MED in mirror nuclei Mg-23-Na-23 up to high spin. The experimental values are compared with state-of-the-art shell model calculations. This permits to enlighten several nuclear structure properties, such as the way in which the nucleons alignment proceeds, the radius variation with J, the role of the spin-orbit interaction and the importance of isospin symmetry breaking terms of nuclear origin., QC 20170508

Published
2017
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28. Spin-dependent evolution of collectivity in Te 112

Author

Doncel, Maria, Bäck, Torbjörn, Qi, C., Cullen, D. M., Hodge, D., Cederwall, Bo, Taylor, M. J., Procter, M., Giles, M., Auranen, K., Grahn, T., Greenlees, P. T., Jakobsson, U., Julin, R., Juutinen, S., Herzáň, A., Konki, J., Pakarinen, J., Partanen, J., Peura, P., Rahkila, P., Ruotsalainen, P., Sandzelius, M., Sarén, J., Scholey, C., Sorri, J., Stolze, S., Uusitalo, J., Doncel, Maria, Bäck, Torbjörn, Qi, C., Cullen, D. M., Hodge, D., Cederwall, Bo, Taylor, M. J., Procter, M., Giles, M., Auranen, K., Grahn, T., Greenlees, P. T., Jakobsson, U., Julin, R., Juutinen, S., Herzáň, A., Konki, J., Pakarinen, J., Partanen, J., Peura, P., Rahkila, P., Ruotsalainen, P., Sandzelius, M., Sarén, J., Scholey, C., Sorri, J., Stolze, S., and Uusitalo, J.

Abstract

The evolution of collectivity with spin along the yrast line in the neutron-deficient nucleus Te112 has been studied by measuring the reduced transition probability of excited states in the yrast band. In particular, the lifetimes of the 4+ and 6+ excited states have been determined by using the recoil distance Doppler-shift method. The results are discussed using both large-scale shell-model and total Routhian surface calculations., QC 20180518

Published
2017
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29. Lifetime measurement of neutron-rich even-even molybdenum isotopes

Author

Ralet, D, Bäck, Torbjörn, Cederwall, Bo, Doncel, Maria, Ghazi Moradi, Farnaz, Zielinska, M., et al., Ralet, D, Bäck, Torbjörn, Cederwall, Bo, Doncel, Maria, Ghazi Moradi, Farnaz, Zielinska, M., and et al.

Abstract

Background: In the neutron-rich A approximate to 100 mass region, rapid shape changes as a function of nucleon number as well as coexistence of prolate, oblate, and triaxial shapes are predicted by various theoretical models. Lifetime measurements of excited levels in the molybdenum isotopes allow the determination of transitional quadrupole moments, which in turn provides structural information regarding the predicted shape change. Purpose: The present paper reports on the experimental setup, the method that allowed one to measure the lifetimes of excited states in even-even molybdenum isotopes from mass A = 100 up to mass A = 108, and the results that were obtained. Method: The isotopes of interest were populated by secondary knock-out reaction of neutron-rich nuclei separated and identified by the GSI fragment separator at relativistic beam energies and detected by the sensitive PreSPEC-AGATA experimental setup. The latter included the Lund-York-Cologne calorimeter for identification, tracking, and velocity measurement of ejectiles, and AGATA, an array of position sensitive segmented HPGe detectors, used to determine the interaction positions of the gamma ray enabling a precise Doppler correction. The lifetimes were determined with a relativistic version of the Doppler-shift-attenuation method using the systematic shift of the energy after Doppler correction of a gamma-ray transition with a known energy. This relativistic Doppler-shift-attenuation method allowed the determination of mean lifetimes from 2 to 250 ps. Results: Even-even molybdenum isotopes from mass A = 100 to A = 108 were studied. The decays of the low-lying states in the ground-state band were observed. In particular, two mean lifetimes were measured for the first time: tau = 29.7(-9.1)(+11.3) ps for the 4(+) state of Mo-108 and tau = 3.2(-0.7)(+ 0.7) ps for the 6(+) state of Mo-102. Conclusions: The reduced transition strengths B(E2), calculated from lifetimes measured in this experiment, compare, QC 20170519

Published
2017
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30. Determination of lifetimes of nuclear excited states using the Recoil Distance Doppler Shift Method in combination with magnetic spectrometers

Author

Doncel, Maria, Gadea, A., Valiente-Dobon, J. J., Quintana, B., Modamio, V., Mengoni, D., Moller, O., Dewald, A., Pietralla, N., Doncel, Maria, Gadea, A., Valiente-Dobon, J. J., Quintana, B., Modamio, V., Mengoni, D., Moller, O., Dewald, A., and Pietralla, N.

Abstract

The current work presents the determination of lifetimes of nuclear excited states using the Recoil Distance Doppler Shift Method, in combination with spectrometers for ion identification, normalizing the intensity of the peaks by the ions detected in the spectrometer as a valid technique that produces results comparable to the ones obtained by the conventional shifted-to-unsifted peak ratio method. The technique has been validated using data measured with the gamma-ray array AGATA, the PRISMA spectrometer and the Cologne plunger setup. In this paper a test performed with the AGATA-PRISMA setup at LNL and the advantages of this new approach with respect to the conventional Recoil Distance Doppler Shift Method are discussed., QC 20171117

Published
2017
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31. Performance and imaging capabilities of the DEGAS high-resolution gamma-ray detector array for the DESPEC experiment at FAIR

Author

Doncel, Maria, Cederwall, Bo, Gadea, A., Gerl, J., Kojouharov, I., Martin, S., Palit, R., Quintana, B., Doncel, Maria, Cederwall, Bo, Gadea, A., Gerl, J., Kojouharov, I., Martin, S., Palit, R., and Quintana, B.

Abstract

Monte Carlo simulations of one of the possible configurations of the imaging phase for the DEGAS spectrometer situated at the DESPEC/NUSTAR experiment have been performed. The geometry consists of the coupling of the high-resolution gamma spectroscopy array, AGATA, with a high-resolution segmented planar detector utilized as an implantation detector in a compact configuration. The sensitivity and performance of the array in terms of efficiency and imaging capability is deduced., QC 20171121

Published
2017
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32. Recoil-decay tagging spectroscopy of W-162(74)88

Author

Li, Hongjie, Cederwall, Bo, Bäck, Torbjörn, Qi, Chong, Doncel, Maria, Jakobsson, Ulrika, Auranen, K., Boenig, S., Drummond, M. C., Grahn, T., Greenlees, P., Herzan, A., Julin, R., Juutinen, S., Konki, J., Kroell, T., Leino, M., McPeake, C., O'Donnell, D., Page, R. D., Pakarinen, J., Partanen, J., Peura, P., Rahkila, P., Ruotsalainen, P., Sandzelius, M., Saren, J., Saygi, B., Scholey, C., Sorri, J., Stolze, S., Taylor, M. J., Thornthwaite, A., Uusitalo, J., and Xiao, Z. G.

Subjects
Physical Sciences, Fysik
Abstract

Excited states in the highly neutron-deficient nucleus W-162 have been investigated via the Mo-92(Kr-78, 2 alpha) W-162 reaction. Prompt gamma rays were detected by the JUROGAM II high-purity germanium detector array and the recoiling fusion-evaporation products were separated by the recoil ion transport unit (RITU) gas-filled recoil separator and identified with the gamma recoil electron alpha tagging (GREAT) spectrometer at the focal plane of RITU. gamma rays from W-162 were identified uniquely using mother-daughter and mother-daughter-granddaughter alpha-decay correlations. The observation of a rotational-like ground-state band is interpreted within the framework of total Routhian surface (TRS) calculations, which suggest an axially symmetric ground-state shape with a gamma-soft minimum at beta(2) approximate to 0.15. Quasiparticle alignment effects are discussed based on cranked shell model calculations. New measurements of the W-162 ground-state alpha-decay energy and half-life were also performed. The observed alpha-decay energy agrees with previous measurements. The half-life of W-162 was determined to be t(1/2) = 990(30) ms. This value deviates significantly from the currently adopted value of t(1/2) = 1360(70) ms. In addition, the alpha-decay energy and half-life of Os-166 were measured and found to agree with the adopted values. QC 20150917

Published
2015

33. Excited states in the proton-unbound nuclide Ta-158

Author

Carroll, R. J., Andgren, Karin, Cederwal, Bo, Doncel, Maria, Hadinia, Baharak, Jakobsson, Ulrika, Sandzelius, Mikael, Taylor, M. J., Thornthwaite, A., et al., Carroll, R. J., Andgren, Karin, Cederwal, Bo, Doncel, Maria, Hadinia, Baharak, Jakobsson, Ulrika, Sandzelius, Mikael, Taylor, M. J., Thornthwaite, A., and et al.

Abstract

Excited states in the neutron-deficient odd-odd proton-unbound nuclide Ta-158 have been investigated in two separate experiments. In the first experiment, Ir-166 nuclei were produced in the reactions of 380 MeV Kr-78 ions with an isotopically enriched Mo-92 target. The alpha-decay chain of the 9(+) state in Ir-166 was analyzed. Fine structure in the a decay of the 9(+) state in Re-162 established a 66 keV difference in excitation energy between the lowest-lying 9(+) and 10(+) states in Ta-158. Higher-lying states in Ta-158 were populated in the reactions of 255 MeV Ni-58 ions with an isotopically enriched Pd-102 target. Gamma-ray decay paths that populate, depopulate, and bypass a 19(-) isomeric state have been identified. The general features of the deduced level scheme are discussed and the prospects for observing proton emission branches from excited states are considered., QC 20160406

Published
2016
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34. Lifetime measurements in Re-166 : Collective versus magnetic rotation

Author

Li, Hongjie, Cederwall, Bo, Doncel, Maria, Bäck, Torbjörn, Jakobsson, Ulrika, Xiao, Z. G., et al., Li, Hongjie, Cederwall, Bo, Doncel, Maria, Bäck, Torbjörn, Jakobsson, Ulrika, Xiao, Z. G., and et al.

Abstract

Lifetimes of excited states in the neutron-deficient odd-odd nucleus Re-166 have been measured for the first time using the recoil distance Doppler-shift method. The measured lifetime for the (8(-)) state; tau = 480 (80) ps, enabled an assessment of the multipolarities of the gamma rays depopulating this state. Information on electromagnetic transition strengths were deduced for the gamma-ray transitions from the (9(-)), (10(-)), and (11(-)) states, and in the case of the (10(-)) and (11(-)) states limits on the B (M1) and B(E2) strengths were estimated. The results are compared with total Routhian surface predictions and semiclassical calculations. Tilted-axis cranking calculations based on a relativistic mean-field approach (TAC-RMF) have also been performed in order to test the possibility of magnetic rotation in the 166Re nucleus. While the TAC-RMF calculations predict a quadrupole-deformed nuclear shape with similar beta(2) deformation as obtained by using the TRS model, it was found that the experimental electromagnetic transition rates are in better agreement with a collective -rotational description., QC 20160406

Published
2016
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35. Character of particle-hole excitations in Ru-94 deduced from gamma-ray angular correlation and linear polarization measurements

Author

Ghazi Moradi, Farnaz, Qi, Chong, Cederwall, Bo, Ataç, Ayşe, Bäck, Torbjörn, Liotta, Roberto, Doncel, Maria, Johnson, Arne, and Aktas, Özge

Subjects
Gamma-ray spectrosopy-polarization, Physical Sciences, Fysik
Abstract

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. QC 20140217. Author count: 35

Published
2014

36. First identification of rotational band structures in Re-166(75)91

Author

Li, Hongjie, Doncel, Maria, Patial, Maria, Cederwall, Bo, Bäck, Torbjörn, Jakobsson, Ulrika, Auranen, K., Boenig, S., Drummond, M., Grahn, T., Greenlees, P., Herzan, A., Joss, D. T., Julin, R., Juutinen, S., Konki, J., Kroell, T., Leino, M., McPeake, C., O'Donnell, D., Page, R. D., Pakarinen, J., Partanen, J., Peura, P., Rahkila, P., Ruotsalainen, P., Sandzelius, M., Saren, J., Saygi, B., Scholey, C., Sorri, J., Stolze, S., Taylor, M. J., Thornthwaite, A., Uusitalo, J., Xiao, Z. G., Li, Hongjie, Doncel, Maria, Patial, Maria, Cederwall, Bo, Bäck, Torbjörn, Jakobsson, Ulrika, Auranen, K., Boenig, S., Drummond, M., Grahn, T., Greenlees, P., Herzan, A., Joss, D. T., Julin, R., Juutinen, S., Konki, J., Kroell, T., Leino, M., McPeake, C., O'Donnell, D., Page, R. D., Pakarinen, J., Partanen, J., Peura, P., Rahkila, P., Ruotsalainen, P., Sandzelius, M., Saren, J., Saygi, B., Scholey, C., Sorri, J., Stolze, S., Taylor, M. J., Thornthwaite, A., Uusitalo, J., and Xiao, Z. G.

Abstract

Excited states in the odd-odd, highly neutron-deficient nucleus Re-166 have been investigated via the Mo-92(Kr-78, 3p1n)Re-166 reaction. Prompt gamma rays were detected by the JUROGAM II. gamma-ray spectrometer, and the recoiling fusion-evaporation products were separated by the recoil ion transport unit (RITU) gas-filled recoil separator and implanted into the Gamma Recoil Electron Alpha Tagging spectrometer located at the RITU focal plane. The tagging and coincidence techniques were applied to identify the gamma-ray transitions in Re-166, revealing two collective, strongly coupled rotational structures, for the first time. The more strongly populated band structure is assigned to the pi h(11/2)[514]9/2(-) circle times vi(13/2)[660]1/2(+) Nilsson configuration, while the weaker structure is assigned to be built on a two-quasiparticle state of mixed pi h(11/2)[514]9/2(-) circle times v[h(9/2)f(7/2)]3/2(-) character. The configuration assignments are based on the electromagnetic characteristics and rotational properties, in comparison with predictions from total Routhian surface and particle-rotor model calculations.

Published
2015
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37. Lifetime measurement of the first excited 2(+) state in Te-112

Author

Doncel, Maria, Bäck, Torbjörn, Cullen, D. M., Hodge, D., Qi, Chong, Cederwall, Bo, Taylor, M. J., Procter, M., Auranen, K., Grahn, T., Greenlees, P. T., Jakobsson, U., Julin, R., Juutinen, S., Herzan, A., Konki, J., Leino, M., Pakarinen, J., Partanen, J., Peura, P., Rahkila, P., Ruotsalainen, P., Sandzelius, M., Saren, J., Scholey, C., Sorri, J., Stolze, S., Uusitalo, J., Doncel, Maria, Bäck, Torbjörn, Cullen, D. M., Hodge, D., Qi, Chong, Cederwall, Bo, Taylor, M. J., Procter, M., Auranen, K., Grahn, T., Greenlees, P. T., Jakobsson, U., Julin, R., Juutinen, S., Herzan, A., Konki, J., Leino, M., Pakarinen, J., Partanen, J., Peura, P., Rahkila, P., Ruotsalainen, P., Sandzelius, M., Saren, J., Scholey, C., Sorri, J., Stolze, S., and Uusitalo, J.

Abstract

The lifetime of the 2(+) --> 0(g.s.)(+) transition in the neutron-deficicient nucleus Te-112 has been measured for the first time using the DPUNS plunger and the recoil distance Doppler shift technique. The deduced value for the reduced transition probability is B(E2 :0(g.s.)(+) --> 2(+)) = 0.46 +/- 0.04 e(2)b(2), indicating that there is no unexpected enhancement of the B(E2 :0(g.s.)(+) --> 2(+)) values in Te isotopes below the midshell. The result is compared to and discussed in the framework of large-scale shell-model calculations., QC 20150713

Published
2015
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38. Shell evolution beyond N=40 : Cu-69,Cu-71,Cu-73

Author

Sahin, E., Doncel, Maria, Sieja, K., de Angelis, G., Gadea, A., Quintana, B., Gorgen, A., Modamio, V., Mengoni, D., Valiente-Dobon, J. J., John, P. R., Albers, M., Bazzacco, D., Benzoni, G., Birkenbach, B., Cederwall, Bo, Clement, E., Curien, D., Corradi, L., Desesquelles, P., Dewald, A., Didierjean, F., Duchene, G., Eberth, J., Erduran, M. N., Farnea, E., Fioretto, E., de France, G., Fransen, C., Gernhaeuser, R., Gottardo, A., Hackstein, M., Hagen, T., Hernandez-Prieto, A., Hess, H., Hueyuek, T., Jungclaus, A., Klupp, S., Korten, W., Kusoglu, A., Lenzi, S. M., Ljungvall, J., Louchart, C., Lunardi, S., Menegazzo, R., Michelagnoli, C., Mijatovic, T., Million, B., Molini, P., Montagnoli, G., Montanari, D., Moeller, O., Napoli, D. R., Obertelli, A., Orlandi, R., Pollarolo, G., Pullia, A., Recchia, F., Reiter, P., Rosso, D., Rother, W., Salsac, M. -D, Scarlassara, F., Schlarb, M., Siem, S., Singh, Pushpendra P., Soderstrom, P. -A, Stefanini, A. M., Stezowski, O., Sulignano, B., Szilner, S., Theisen, Ch, Ur, C. A., Yalcinkaya, M., Sahin, E., Doncel, Maria, Sieja, K., de Angelis, G., Gadea, A., Quintana, B., Gorgen, A., Modamio, V., Mengoni, D., Valiente-Dobon, J. J., John, P. R., Albers, M., Bazzacco, D., Benzoni, G., Birkenbach, B., Cederwall, Bo, Clement, E., Curien, D., Corradi, L., Desesquelles, P., Dewald, A., Didierjean, F., Duchene, G., Eberth, J., Erduran, M. N., Farnea, E., Fioretto, E., de France, G., Fransen, C., Gernhaeuser, R., Gottardo, A., Hackstein, M., Hagen, T., Hernandez-Prieto, A., Hess, H., Hueyuek, T., Jungclaus, A., Klupp, S., Korten, W., Kusoglu, A., Lenzi, S. M., Ljungvall, J., Louchart, C., Lunardi, S., Menegazzo, R., Michelagnoli, C., Mijatovic, T., Million, B., Molini, P., Montagnoli, G., Montanari, D., Moeller, O., Napoli, D. R., Obertelli, A., Orlandi, R., Pollarolo, G., Pullia, A., Recchia, F., Reiter, P., Rosso, D., Rother, W., Salsac, M. -D, Scarlassara, F., Schlarb, M., Siem, S., Singh, Pushpendra P., Soderstrom, P. -A, Stefanini, A. M., Stezowski, O., Sulignano, B., Szilner, S., Theisen, Ch, Ur, C. A., and Yalcinkaya, M.

Abstract

The level structure of the neutron-rich Cu-69, Cu-71, and Cu-73 isotopes has been investigated by means of multinucleon transfer reactions. The experiment was performed at Laboratori Nazionali di Legnaro using the AGATA Demonstrator array coupled to the PRISMA magnetic spectrometer. Lifetimes of excited states in Cu nuclei were measured with the recoil-distance Doppler-shift method. The resulting electromagnetic matrix elements for transitions from excited states in Cu-69,Cu-71,Cu-73 nuclei are used to assess the collective or single-particle character of these states. The results are compared with predictions of large-scale shell-model calculations, giving further insight into the evolution of the proton pf shell as neutrons fill the 1g(9/2) orbital., QC 20150507

Published
2015
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39. Oblately deformed isomeric proton-emitting state in Lu-151

Author

Taylor, M. J., Cullen, D. M., Procter, M. G., Smith, A. J., McFarlane, A., Twist, V., Alharshan, G. A., Ferreira, L. S., Maglione, E., Auranen, K., Grahn, T., Greenlees, P. T., Hauschild, K., Herzan, A., Jakobsson, U., Julin, R., Juutinen, S., Ketelhut, S., Konki, J., Leino, M., Lopez-Martens, A., Pakarinen, J., Partanen, J., Peura, P., Rahkila, P., Rinta-Antila, S., Ruotsalainen, P., Sandzelius, M., Saren, J., Scholey, C., Sorri, J., Stolze, S., Uusitalo, J., Doncel, Maria, Taylor, M. J., Cullen, D. M., Procter, M. G., Smith, A. J., McFarlane, A., Twist, V., Alharshan, G. A., Ferreira, L. S., Maglione, E., Auranen, K., Grahn, T., Greenlees, P. T., Hauschild, K., Herzan, A., Jakobsson, U., Julin, R., Juutinen, S., Ketelhut, S., Konki, J., Leino, M., Lopez-Martens, A., Pakarinen, J., Partanen, J., Peura, P., Rahkila, P., Rinta-Antila, S., Ruotsalainen, P., Sandzelius, M., Saren, J., Scholey, C., Sorri, J., Stolze, S., Uusitalo, J., and Doncel, Maria

Abstract

Gamma rays from excited states feeding a proton-emitting isomeric-state in Lu-151 have been observed for the first time. Comparison with state-of-the-art nonadiabatic quasiparticle calculations indicates an oblately deformed, 3/2(+) proton-emitting state with a quadrupole deformation of beta(2) = -0.11. The calculations suggest an increase in quadrupole deformation, to beta(2) = -0.18, with increasing spin which is understood in terms of the mixing of Nilsson states at the Fermi surface. It is also shown that the proton decay half-life is consistent with that from a 3/2(+) state with a quadrupole deformation of beta(2) = -0.12., QC 20150807

Published
2015
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40. Conceptual design of a high resolution Ge array with tracking and imaging capabilities for the DESPEC (FAIR) experiment

Author

Doncel, Maria, Cederwall, Bo, Martin, S., Quintana, B., Gadea, A., Farnea, E., Algora, A., Doncel, Maria, Cederwall, Bo, Martin, S., Quintana, B., Gadea, A., Farnea, E., and Algora, A.

Abstract

We present results of Monte Carlo simulations for the conceptual design of the high-resolution DESPEC Germanium Array Spectrometer (DEGAS) proposed for the Facility for Ion and Antiproton Research (FAIR) under construction at Darmstadt, Germany. The project is carried out in three phases, although only results for the two first phases will be addressed in this work. The first phase will consist of a re-arrangement of the EUROBALL cluster detectors previously used in the RISING campaign at GSI. The second phase is based on coupling AGATA-type triple-cluster detectors with EUROBALL cluster detectors in a compact geometry around the active ion implantation target of DESPEC., QC 20150817

Published
2015
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41. Spectroscopy of the neutron-deficient N=50 nucleus Rh-95

Author

Ghazi Moradi, Farnaz, Cederwall, Bo, Qi, Chong, Bäck, Torbjörn, Ataç, Ayşe, Liotta, Roberto, Doncel, Maria, Johnson, Arne, 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, Özge, Di Nitto, A., Dijon, A., Hueyuek, T., Jaworski, G., John, P. R., Yilmaz, B., Ghazi Moradi, Farnaz, Cederwall, Bo, Qi, Chong, Bäck, Torbjörn, Ataç, Ayşe, Liotta, Roberto, Doncel, Maria, Johnson, Arne, 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, Özge, Di Nitto, A., Dijon, A., Hueyuek, T., Jaworski, G., John, P. R., and Yilmaz, B.

Abstract

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., QC 20140516. Updated from manuscript to article in journal.

Published
2014
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42. Spectroscopy of the neutron deficient N=50 nucleus 95Rh

Author

Ghazi Moradi, Farnaz, Cederwall, Bo, Qi, Chong, Ataç, Ayşe, Liotta, Roberto, Doncel, Maria, Johnson, Arne, et al., Ghazi Moradi, Farnaz, Cederwall, Bo, Qi, Chong, Ataç, Ayşe, Liotta, Roberto, Doncel, Maria, Johnson, Arne, and et al.

Abstract

QS 2014

Published
2014

43. Lifetime Measurements in Neutron-rich Cu Isotopes

Author

Doncel, Maria, Sahin, E., Gadea, A., de Angelis, G., Quintana, B., Valiente-Dobon, J. J., Modamio, V., Albers, M., Bazzacco, D., Clement, E., Corradi, L., Dewald, A., Duchene, G., Erduran, M. N., Farnea, E., Fioretto, E., Fransen, C., Gernhaeuser, R., Goergen, A., Gottardo, A., Hackstein, M., Hernandez-Prieto, A., Hueyuek, T., Klupp, S., Korten, W., Kusoglu, A., Lenzi, S., Louchart, C., Lunardi, S., Menegazzo, R., Mengoni, D., Michelagnoli, C., Mijatovic, T., Montagnoli, G., Montanari, D., Moeller, O., Napoli, D. R., Obertelli, A., Orlandi, R., Pollarolo, G., Recchia, F., Rother, W., Salsac, M. -D, Scarlassara, F., Schlarb, M., Stefanini, A., Sulignano, B., Szilner, S., Ur, C. A., Doncel, Maria, Sahin, E., Gadea, A., de Angelis, G., Quintana, B., Valiente-Dobon, J. J., Modamio, V., Albers, M., Bazzacco, D., Clement, E., Corradi, L., Dewald, A., Duchene, G., Erduran, M. N., Farnea, E., Fioretto, E., Fransen, C., Gernhaeuser, R., Goergen, A., Gottardo, A., Hackstein, M., Hernandez-Prieto, A., Hueyuek, T., Klupp, S., Korten, W., Kusoglu, A., Lenzi, S., Louchart, C., Lunardi, S., Menegazzo, R., Mengoni, D., Michelagnoli, C., Mijatovic, T., Montagnoli, G., Montanari, D., Moeller, O., Napoli, D. R., Obertelli, A., Orlandi, R., Pollarolo, G., Recchia, F., Rother, W., Salsac, M. -D, Scarlassara, F., Schlarb, M., Stefanini, A., Sulignano, B., Szilner, S., and Ur, C. A.

Abstract

The nuclear structure of neutron-rich nuclei close to the double-magic nucleus Ni-78 has been investigated by measuring the lifetime of excited states. In this contribution, it will be presented the lifetime of the J(pi) = 7/2(-) excited state at 981 keV of the Cu-71 isotope, measured using the AGATA Demonstrator coupled to the PRISMA spectrometer and the Koln plunger setup. This is the first time this combined setup has been used for a lifetime measurement., QC 20130520

Published
2013
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44. Competing single-particle and collective states in the low-energy structure of I-113

Author

Taylor, M. J., Cullen, D. M., Procter, M. G., Bäck, Torbjörn, Cederwall, Bo, Doncel, Maria, Braunroth, T., Dewald, A., Pakarinen, J., Grahn, T., Greenlees, P. T., Auranen, K., Jakobsson, U., Julin, R., Juutinen, S., Herzan, A., Konki, J., Leino, M., Liotta, R., Partanen, J., Peura, P., Rahkila, P., Ruotsalainen, P., Sandzelius, M., Saren, J., Sorri, J., Stolze, S., Uusitalo, J., Liang, W. Y., Xu, F. R., Taylor, M. J., Cullen, D. M., Procter, M. G., Bäck, Torbjörn, Cederwall, Bo, Doncel, Maria, Braunroth, T., Dewald, A., Pakarinen, J., Grahn, T., Greenlees, P. T., Auranen, K., Jakobsson, U., Julin, R., Juutinen, S., Herzan, A., Konki, J., Leino, M., Liotta, R., Partanen, J., Peura, P., Rahkila, P., Ruotsalainen, P., Sandzelius, M., Saren, J., Sorri, J., Stolze, S., Uusitalo, J., Liang, W. Y., and Xu, F. R.

Abstract

To understand the low-energy structure of the neutron deficient iodine isotopes, lifetimes for the low-lying 9/2(+) and 11/2(+) positive-parity states in I-113 have been measured as tau = 28(4) ps and tau = 3.7(7) ps, respectively. The lifetime for the 11/2(-) state, which feeds the 9/2(+) and 11/2(+) states, was remeasured with improved accuracy as tau = 216(7) ps. The reduced transition probability, B(E2) = 32(5) W.u., for the 9/2(+) -> 5/2(+) transition agrees with that calculated within the shell model using a Hamiltonian based on the charge-dependent Bonn nucleon-nucleon interaction. In contrast, the much larger transition probability, B(E2) = 209(39) W.u., measured for the 11/2(+) -> 7/2(+) transition has been interpreted, with the aid of configuration-constrained total Routhian surface calculations, as resulting from a slightly gamma-soft rotor with an associated quadrupole deformation of beta(2) approximate to 0.18. Remarkably similar reduced E1 transition probabilities of 5.5(5) x 10(-4) and 4.9(5) x 10(-4) W.u. were deduced for the 11/2(-) -> 9/2(+) and 11/2(-) -> 11/2(+) transitions, respectively, which feed apparently dissimilar but competing structures., QC 20131210

Published
2013
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45. M1 and E2 transition rates from core-excited states in semi-magic 94Ru

Author

Ertoprak, Aysegul, Cederwall, Bo, Qi, Chong, Doncel, Maria, Jakobsson, U., Nyako, B. M., Jaworski, G, Davies, P., De France, G., Kuti, I., Napoli, D. R., Wadsworth, R., Ghugre, S. S., Raut, R., Al-Azri, H., Algora, A., de Angelis, G., Atac, A., Bäck, Torbjörn, Boso, A., Clement, E., Debenham, D. M., Dombradi, Zs., Erturk, S., Gadea, A., Ghazi Moradi, Farnaz, Gottardo, A., Huyuk, T., Ideguchi, E., Li, H., Michelagnoli, C., Modamio, V., Nyberg, J., Palacz, M., Petrache, C. M., Recchia, F., Sandzelius, M., Siciliano, M., Timar, J., Valiente-Dobon, J. J., Xiao, Z. G., Ertoprak, Aysegul, Cederwall, Bo, Qi, Chong, Doncel, Maria, Jakobsson, U., Nyako, B. M., Jaworski, G, Davies, P., De France, G., Kuti, I., Napoli, D. R., Wadsworth, R., Ghugre, S. S., Raut, R., Al-Azri, H., Algora, A., de Angelis, G., Atac, A., Bäck, Torbjörn, Boso, A., Clement, E., Debenham, D. M., Dombradi, Zs., Erturk, S., Gadea, A., Ghazi Moradi, Farnaz, Gottardo, A., Huyuk, T., Ideguchi, E., Li, H., Michelagnoli, C., Modamio, V., Nyberg, J., Palacz, M., Petrache, C. M., Recchia, F., Sandzelius, M., Siciliano, M., Timar, J., Valiente-Dobon, J. J., and Xiao, Z. G.

Abstract

Lifetimes of high-spin states have been measured in the semi-magic (N=50) nucleus 94Ru. Excited states in 94Ru were populated in the 58Ni(40Ca, 4p)94Ru∗ fusion-evaporation reaction at the Grand Accelerateur National d’Ions Lourds (GANIL) accelerator complex. DSAM lifetime analysis was performed on the Doppler broadened line shapes in energy spectra obtained from γ-rays emitted while the residual nuclei were slowing down in a thick 6 mg/cm2 metallic 58Ni target. In total eight excited-state lifetimes in the angular momentum range I = (13 − 20)ħ have been measured, five of which were determined for the first time. The deduced corresponding B(M1) and B(E2)reduced transition strengths are discussed within the framework of large-scale shell model calculations to study the contribution of different particle-hole configurations, in particular for analyzing contributions from core-excited configurations., QC 20171109

46. Lifetime measurements of core-excited states in semi-magic 95Rh

Author

Ertoprak, Aysegul, Qi, Chong, Cederwall, Bo, Doncel, Maria, Jakobsson, U., Nyako, B., Jaworski, G., Davies, P., de France, G., Kuti, I., Napoli, D. R., Wadsworth, R., Ghugre, S. S., Raut, R., Akkus, B., Al-Azri, H., Algora, A., de Angelis, G., Atac Nyberg, Ayse, Bäck, Torbjörn, Boso, A., Clement, E., Debenham, D. M., Dombradi, Zs., Erturk, S., Gadea, A., Ghazi Moradi, Farnaz, Gottardo, A., Huyuk, T, Ideguchi, E., Li, Hongjie J., Michelagnoli, C., Modamio, V., Nyberg, J., Palacz, M., Petrache, C. M., Recchia, F., Sandzelius, M., Siciliano, M., Timar, J., Valiente-Dobon, J. J., Xiao, Z. G., Ertoprak, Aysegul, Qi, Chong, Cederwall, Bo, Doncel, Maria, Jakobsson, U., Nyako, B., Jaworski, G., Davies, P., de France, G., Kuti, I., Napoli, D. R., Wadsworth, R., Ghugre, S. S., Raut, R., Akkus, B., Al-Azri, H., Algora, A., de Angelis, G., Atac Nyberg, Ayse, Bäck, Torbjörn, Boso, A., Clement, E., Debenham, D. M., Dombradi, Zs., Erturk, S., Gadea, A., Ghazi Moradi, Farnaz, Gottardo, A., Huyuk, T, Ideguchi, E., Li, Hongjie J., Michelagnoli, C., Modamio, V., Nyberg, J., Palacz, M., Petrache, C. M., Recchia, F., Sandzelius, M., Siciliano, M., Timar, J., Valiente-Dobon, J. J., and Xiao, Z. G.

Abstract

Lifetimes of negative-parity states have been determined in the semi-magic (N=50) nucleus 95Rh. The fusion-evaporation reaction 58Ni(40Ca, 3p) was used to populate high-spin states in 95Rh at the Grand Accelerateur National d'Ions Lourds (GANIL) accelerator facility. The results were obtained using the Doppler Shift Attenuation Method (DSAM) based on the Doppler broadened line shapes produced during the slowing down process of the residual nuclei in a thick 6~ mg/cm2 metallic target. B(M1) and B(E2) reduced transition strengths are compared with predictions from large-scale shell-model calculations., QC 20200409

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