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334 results on '"Warr, N."'

1. Study of bound states in ¹⁰Be by one neutron removal reactions of ¹¹Be

Author: Johansen, Jacob G., Bildstein, V., Borge, M. J. G., Cubero, M., Diriken, J., Elseviers, J., Fraile, L. M., Fynbo, H. O. U., Gaffney, L. P., Gernhäuser, R., Jonson, B., Koldste, G. T., Konki, J., Kröll, T., Krücken, R., Mücher, D., Nilsson, T., Nowak, K., Pakarinen, J., Pesudo, V., Raabe, R., Riisager, K., Seidlitz, M., Tengblad, O., Törnqvist, H., Voulot, D., Warr, N., Wimmer, K., De Witte, H., Johansen, Jacob G., Bildstein, V., Borge, M. J. G., Cubero, M., Diriken, J., Elseviers, J., Fraile, L. M., Fynbo, H. O. U., Gaffney, L. P., Gernhäuser, R., Jonson, B., Koldste, G. T., Konki, J., Kröll, T., Krücken, R., Mücher, D., Nilsson, T., Nowak, K., Pakarinen, J., Pesudo, V., Raabe, R., Riisager, K., Seidlitz, M., Tengblad, O., Törnqvist, H., Voulot, D., Warr, N., Wimmer, K., and De Witte, H.
Abstract: The bound states of ¹⁰Be have been studied by removing single neutrons from ¹¹Be nuclei. A 2.8 MeV u⁻¹ beam of ¹¹Be was produced at ISOLDE, CERN and directed on to both proton and deuteron targets inducing one-neutron removal reactions. Charged particles were detected to identify the two reaction channels (d, t) and (p, d), and the individual states in ¹⁰Be were identified by gamma detection. All bound states but one were populated and identified in the (d, t) reaction. The combination of REX-ISOLDE and MINIBALL allowed for a clean separation of the high-lying states in ¹⁰Be. This is the first time these states have been separated in a reaction experiment. Differential cross sections have been calculated for all the reaction channels and compared to DWBA calculations. Spectroscopic factors are derived and compared to values from the litterature. While the overall agreement between the spectrocopic factors is poor, the ratio between the ground state and the first excited state is in agreement with the previous measured ones. Furthermore, a significant population of the 2⁺₂ state is observed, which which may indicate the presence of multi-step processes at our beam energy.
Published: 2024

2. Study of bound states in ¹⁰Be by one neutron removal reactions of ¹¹Be

Author: Johansen, Jacob G., Bildstein, V., Borge, M. J. G., Cubero, M., Diriken, J., Elseviers, J., Fraile, L. M., Fynbo, H. O. U., Gaffney, L. P., Gernhäuser, R., Jonson, B., Koldste, G. T., Konki, J., Kröll, T., Krücken, R., Mücher, D., Nilsson, T., Nowak, K., Pakarinen, J., Pesudo, V., Raabe, R., Riisager, K., Seidlitz, M., Tengblad, O., Törnqvist, H., Voulot, D., Warr, N., Wimmer, K., De Witte, H., Johansen, Jacob G., Bildstein, V., Borge, M. J. G., Cubero, M., Diriken, J., Elseviers, J., Fraile, L. M., Fynbo, H. O. U., Gaffney, L. P., Gernhäuser, R., Jonson, B., Koldste, G. T., Konki, J., Kröll, T., Krücken, R., Mücher, D., Nilsson, T., Nowak, K., Pakarinen, J., Pesudo, V., Raabe, R., Riisager, K., Seidlitz, M., Tengblad, O., Törnqvist, H., Voulot, D., Warr, N., Wimmer, K., and De Witte, H.
Abstract: The bound states of ¹⁰Be have been studied by removing single neutrons from ¹¹Be nuclei. A 2.8 MeV u⁻¹ beam of ¹¹Be was produced at ISOLDE, CERN and directed on to both proton and deuteron targets inducing one-neutron removal reactions. Charged particles were detected to identify the two reaction channels (d, t) and (p, d), and the individual states in ¹⁰Be were identified by gamma detection. All bound states but one were populated and identified in the (d, t) reaction. The combination of REX-ISOLDE and MINIBALL allowed for a clean separation of the high-lying states in ¹⁰Be. This is the first time these states have been separated in a reaction experiment. Differential cross sections have been calculated for all the reaction channels and compared to DWBA calculations. Spectroscopic factors are derived and compared to values from the litterature. While the overall agreement between the spectrocopic factors is poor, the ratio between the ground state and the first excited state is in agreement with the previous measured ones. Furthermore, a significant population of the 2⁺₂ state is observed, which which may indicate the presence of multi-step processes at our beam energy.
Published: 2024

3. Low collectivity of the first 2⁺ states of ²¹²,²¹⁰Po

Author: Kocheva, D., Rainovski, G., Jolie, J., Pietralla, N., Blazhev, A., Astier, A., Altenkirch, R., Bast, M., Beckers, M., Ansari, S., Braunroth, Th., Cappellazzo, M., Cortés, M.L., Dewald, A., Diel, F., Djongolov, M., Fransen, C., Gladnishki, K., Goldkuhle, A., Hennig, A., Karayonchev, V., Keatings, J.M., Kluge, E., Kröll, Th., Litzinger, J., Moschner, K., Müller-Gatermann, C., Petkov, P., Rudigier, M., Scheck, M., Spagnoletti, P., Scholz, Ph., Schmidt, T., Spieker, M., Stahl, C., Stegmann, R., Stolz, A., Vogt, A., Stoyanova, M., Thöle, P., Warr, N., Werner, V., Witt, W., Wölk, D., Zamora, J.C., Zell, K.O., Van Isacker, P., Ponomarev, V. Yu., Kocheva, D., Rainovski, G., Jolie, J., Pietralla, N., Blazhev, A., Astier, A., Altenkirch, R., Bast, M., Beckers, M., Ansari, S., Braunroth, Th., Cappellazzo, M., Cortés, M.L., Dewald, A., Diel, F., Djongolov, M., Fransen, C., Gladnishki, K., Goldkuhle, A., Hennig, A., Karayonchev, V., Keatings, J.M., Kluge, E., Kröll, Th., Litzinger, J., Moschner, K., Müller-Gatermann, C., Petkov, P., Rudigier, M., Scheck, M., Spagnoletti, P., Scholz, Ph., Schmidt, T., Spieker, M., Stahl, C., Stegmann, R., Stolz, A., Vogt, A., Stoyanova, M., Thöle, P., Warr, N., Werner, V., Witt, W., Wölk, D., Zamora, J.C., Zell, K.O., Van Isacker, P., and Ponomarev, V. Yu.
Abstract: The lifetimes of the first 2⁺ excited states of ²¹²,²¹⁰Po were measured in two transfer reactions ²⁰⁸Pb(¹²C,⁸Be)²¹²Po and ²⁰⁸Pb(¹²C,¹⁰Be)²¹⁰Po by the Recoil Distance Doppler Shift (RDDS) method and by the Doppler Shift Attenuation method (DSAM), respectively. The derived absolute B(E2) values of 2.6(3) W.u. for ²¹²Po and 1.83(28) W.u. for ²¹⁰Po indicate low collectivity. It is shown that the properties of the yrast 2₁⁺, 4₁⁺, 6₁⁺ and 8₁⁺ states in both nuclei cannot be described consistently in the framework of nuclear shell models. It is also demonstrated in the case of ²¹⁰Po that Quasi-particle Phonon Model (QPM) calculations cannot overcome this problem thus indicating the existence of a peculiarity which is neglected in both theoretical approaches.
Published: 2024

4. Low collectivity of the first 2⁺ states of ²¹²,²¹⁰Po

Author: Kocheva, D., Rainovski, G., Jolie, J., Pietralla, N., Blazhev, A., Astier, A., Altenkirch, R., Bast, M., Beckers, M., Ansari, S., Braunroth, Th., Cappellazzo, M., Cortés, M.L., Dewald, A., Diel, F., Djongolov, M., Fransen, C., Gladnishki, K., Goldkuhle, A., Hennig, A., Karayonchev, V., Keatings, J.M., Kluge, E., Kröll, Th., Litzinger, J., Moschner, K., Müller-Gatermann, C., Petkov, P., Rudigier, M., Scheck, M., Spagnoletti, P., Scholz, Ph., Schmidt, T., Spieker, M., Stahl, C., Stegmann, R., Stolz, A., Vogt, A., Stoyanova, M., Thöle, P., Warr, N., Werner, V., Witt, W., Wölk, D., Zamora, J.C., Zell, K.O., Van Isacker, P., Ponomarev, V. Yu., Kocheva, D., Rainovski, G., Jolie, J., Pietralla, N., Blazhev, A., Astier, A., Altenkirch, R., Bast, M., Beckers, M., Ansari, S., Braunroth, Th., Cappellazzo, M., Cortés, M.L., Dewald, A., Diel, F., Djongolov, M., Fransen, C., Gladnishki, K., Goldkuhle, A., Hennig, A., Karayonchev, V., Keatings, J.M., Kluge, E., Kröll, Th., Litzinger, J., Moschner, K., Müller-Gatermann, C., Petkov, P., Rudigier, M., Scheck, M., Spagnoletti, P., Scholz, Ph., Schmidt, T., Spieker, M., Stahl, C., Stegmann, R., Stolz, A., Vogt, A., Stoyanova, M., Thöle, P., Warr, N., Werner, V., Witt, W., Wölk, D., Zamora, J.C., Zell, K.O., Van Isacker, P., and Ponomarev, V. Yu.
Abstract: The lifetimes of the first 2⁺ excited states of ²¹²,²¹⁰Po were measured in two transfer reactions ²⁰⁸Pb(¹²C,⁸Be)²¹²Po and ²⁰⁸Pb(¹²C,¹⁰Be)²¹⁰Po by the Recoil Distance Doppler Shift (RDDS) method and by the Doppler Shift Attenuation method (DSAM), respectively. The derived absolute B(E2) values of 2.6(3) W.u. for ²¹²Po and 1.83(28) W.u. for ²¹⁰Po indicate low collectivity. It is shown that the properties of the yrast 2₁⁺, 4₁⁺, 6₁⁺ and 8₁⁺ states in both nuclei cannot be described consistently in the framework of nuclear shell models. It is also demonstrated in the case of ²¹⁰Po that Quasi-particle Phonon Model (QPM) calculations cannot overcome this problem thus indicating the existence of a peculiarity which is neglected in both theoretical approaches.
Published: 2024

5. Study of bound states in ¹⁰Be by one neutron removal reactions of ¹¹Be

Author: Johansen, Jacob G., Bildstein, V., Borge, M. J. G., Cubero, M., Diriken, J., Elseviers, J., Fraile, L. M., Fynbo, H. O. U., Gaffney, L. P., Gernhäuser, R., Jonson, B., Koldste, G. T., Konki, J., Kröll, T., Krücken, R., Mücher, D., Nilsson, T., Nowak, K., Pakarinen, J., Pesudo, V., Raabe, R., Riisager, K., Seidlitz, M., Tengblad, O., Törnqvist, H., Voulot, D., Warr, N., Wimmer, K., De Witte, H., Johansen, Jacob G., Bildstein, V., Borge, M. J. G., Cubero, M., Diriken, J., Elseviers, J., Fraile, L. M., Fynbo, H. O. U., Gaffney, L. P., Gernhäuser, R., Jonson, B., Koldste, G. T., Konki, J., Kröll, T., Krücken, R., Mücher, D., Nilsson, T., Nowak, K., Pakarinen, J., Pesudo, V., Raabe, R., Riisager, K., Seidlitz, M., Tengblad, O., Törnqvist, H., Voulot, D., Warr, N., Wimmer, K., and De Witte, H.
Abstract: The bound states of ¹⁰Be have been studied by removing single neutrons from ¹¹Be nuclei. A 2.8 MeV u⁻¹ beam of ¹¹Be was produced at ISOLDE, CERN and directed on to both proton and deuteron targets inducing one-neutron removal reactions. Charged particles were detected to identify the two reaction channels (d, t) and (p, d), and the individual states in ¹⁰Be were identified by gamma detection. All bound states but one were populated and identified in the (d, t) reaction. The combination of REX-ISOLDE and MINIBALL allowed for a clean separation of the high-lying states in ¹⁰Be. This is the first time these states have been separated in a reaction experiment. Differential cross sections have been calculated for all the reaction channels and compared to DWBA calculations. Spectroscopic factors are derived and compared to values from the litterature. While the overall agreement between the spectrocopic factors is poor, the ratio between the ground state and the first excited state is in agreement with the previous measured ones. Furthermore, a significant population of the 2⁺₂ state is observed, which which may indicate the presence of multi-step processes at our beam energy.
Published: 2024

6. Axial and triaxial degrees of freedom in 72Zn

Author: Hellgartner, S, Hellgartner, S, Mücher, D, Wimmer, K, Bildstein, V, Egido, JL, Gernhäuser, R, Krücken, R, Nowak, AK, Zielińska, M, Bauer, C, Benito, MLL, Bottoni, S, De Witte, H, Elseviers, J, Fedorov, D, Flavigny, F, Illana, A, Klintefjord, M, Kröll, T, Lutter, R, Marsh, B, Orlandi, R, Pakarinen, J, Raabe, R, Rapisarda, E, Reichert, S, Reiter, P, Scheck, M, Seidlitz, M, Siebeck, B, Siesling, E, Steinbach, T, Stora, T, Vermeulen, M, Voulot, D, Warr, N, Wenander, FJC, Hellgartner, S, Hellgartner, S, Mücher, D, Wimmer, K, Bildstein, V, Egido, JL, Gernhäuser, R, Krücken, R, Nowak, AK, Zielińska, M, Bauer, C, Benito, MLL, Bottoni, S, De Witte, H, Elseviers, J, Fedorov, D, Flavigny, F, Illana, A, Klintefjord, M, Kröll, T, Lutter, R, Marsh, B, Orlandi, R, Pakarinen, J, Raabe, R, Rapisarda, E, Reichert, S, Reiter, P, Scheck, M, Seidlitz, M, Siebeck, B, Siesling, E, Steinbach, T, Stora, T, Vermeulen, M, Voulot, D, Warr, N, and Wenander, FJC
Published: 2023

7. Nuclear Level Density and $\gamma$-ray Strength Function of $^{67}\mathrm{Ni}$ and the impact on the i-process

Author: Ingeberg, V. W., Siem, S., Wiedeking, M., Choplin, A., Goriely, S., Siess, L., Abrahams, K. J., Arnswald, K., Garrote, F. Bello, Bleuel, D. L., Cederkäll, J., Christoffersen, T. L., Cox, D. M., De Witte, H., Gaffney, L. P., Görgen, A., Henrich, C., Illana, A., Jones, P., Kheswa, B. V., Kröll, T., Majola, S. N. T., Malatji, K. L., Ojala, J., Pakarinen, J., Rainovski, G., Reiter, P., von Schmid, M., Seidlitz, M., Tveten, G. M., Warr, N., Zeiser, F., Ingeberg, V. W., Siem, S., Wiedeking, M., Choplin, A., Goriely, S., Siess, L., Abrahams, K. J., Arnswald, K., Garrote, F. Bello, Bleuel, D. L., Cederkäll, J., Christoffersen, T. L., Cox, D. M., De Witte, H., Gaffney, L. P., Görgen, A., Henrich, C., Illana, A., Jones, P., Kheswa, B. V., Kröll, T., Majola, S. N. T., Malatji, K. L., Ojala, J., Pakarinen, J., Rainovski, G., Reiter, P., von Schmid, M., Seidlitz, M., Tveten, G. M., Warr, N., and Zeiser, F.
Abstract: Proton-$\gamma$ coincidences from $(\mathrm{d},\mathrm{p})$ reactions between a $^{66}\mathrm{Ni}$ beam and a deuterated polyethylene target have been analyzed with the inverse Oslo method to find the nuclear level density (NLD) and $\gamma$-ray strength function ($\gamma$SF) of $^{67}\mathrm{Ni}$. The $^{66}\mathrm{Ni}(\mathrm{n},\gamma)$ capture cross section has been calculated using the Hauser-Feshbach model in TALYS using the measured NLD and $\gamma$SF as constraints. We confirm that $^{66}\mathrm{Ni}(\mathrm{n},\gamma)$ acts as a bottleneck when relying on one-zone nucleosynthesis calculations. However, we find that the impact of this reaction is strongly damped in multi-zone low-metallicity AGB stellar models experiencing i-process nucleosynthesis., Comment: Submitted to Phys. Rev. C
Published: 2023

8. Coulomb excitation of Zn 74,76

Author: European Commission, Research Foundation - Flanders, Federal Ministry of Education and Research (Germany), Ministry of Science and Higher Education (Poland), Ministerio de Ciencia e Innovación (España), National Science Centre (Poland), RIKEN Nishina Center for Accelerator-Based Science, Illana, A. [0000-0003-0274-3388], Zielińska, M. [0000-0001-5622-6349], Van Duppen, P. [0000-0002-5053-7370], Wrzosek-Lipska, K. [0000-0003-0046-1387], Lenzi, S. M. [0000-0002-4666-8431], Nowacki, F. [0000-0002-7854-8717], Dao, D. D. [0000-0001-9884-4591], Otsuka, T. [0000-0002-1593-5322], Tsunoda, Y. [0000-0002-0398-1639], Illana, A., Zielińska, M., Huyse, M., Rapisarda, E., Van Duppen, P., Wrzosek-Lipska, K., Lenzi, S. M., Nowacki, F., Dao, D. D., Otsuka, T., Tsunoda, Y., Arnswald, K., García Borge, María José, Cederkäll, J., Chrysalidis, K., Cortés, M. L., Cox, D. M., Day Goodacre, T., De Witte, H., Doherty, D. T., Fedosseev, V., Gaffney, L. P., Hadyńska-Klek, K., Hess, H., Henrich, C., Hlebowicz, M., Komorowska, M., Korten, W., Kröll, Th, Lozano Benito, M. L., Lutter, R., Marsh, B., Martikainen, L., Matejska-Minda, M., Molkanov, P. L., Nacher, Enrique, Nannini, A., Napiorkowski, P. J., Pakarinen, J., Papadakis, P., Queiser, M., Reiter, P., Rocchini, M., Rodriguez, J. A., Rolke, T., Rosiak, D., Rothe, S., Seidlitz, M., Seiffert, C., Siebeck, B., Siesling, E., Snäll, J., Srebrny, J., Thiel, S., Warr, N., Wenander, F., European Commission, Research Foundation - Flanders, Federal Ministry of Education and Research (Germany), Ministry of Science and Higher Education (Poland), Ministerio de Ciencia e Innovación (España), National Science Centre (Poland), RIKEN Nishina Center for Accelerator-Based Science, Illana, A. [0000-0003-0274-3388], Zielińska, M. [0000-0001-5622-6349], Van Duppen, P. [0000-0002-5053-7370], Wrzosek-Lipska, K. [0000-0003-0046-1387], Lenzi, S. M. [0000-0002-4666-8431], Nowacki, F. [0000-0002-7854-8717], Dao, D. D. [0000-0001-9884-4591], Otsuka, T. [0000-0002-1593-5322], Tsunoda, Y. [0000-0002-0398-1639], Illana, A., Zielińska, M., Huyse, M., Rapisarda, E., Van Duppen, P., Wrzosek-Lipska, K., Lenzi, S. M., Nowacki, F., Dao, D. D., Otsuka, T., Tsunoda, Y., Arnswald, K., García Borge, María José, Cederkäll, J., Chrysalidis, K., Cortés, M. L., Cox, D. M., Day Goodacre, T., De Witte, H., Doherty, D. T., Fedosseev, V., Gaffney, L. P., Hadyńska-Klek, K., Hess, H., Henrich, C., Hlebowicz, M., Komorowska, M., Korten, W., Kröll, Th, Lozano Benito, M. L., Lutter, R., Marsh, B., Martikainen, L., Matejska-Minda, M., Molkanov, P. L., Nacher, Enrique, Nannini, A., Napiorkowski, P. J., Pakarinen, J., Papadakis, P., Queiser, M., Reiter, P., Rocchini, M., Rodriguez, J. A., Rolke, T., Rosiak, D., Rothe, S., Seidlitz, M., Seiffert, C., Siebeck, B., Siesling, E., Snäll, J., Srebrny, J., Thiel, S., Warr, N., and Wenander, F.
Abstract: The first experiment using radioactive beams post-accelerated by the HIE-ISOLDE facility has enabled to obtain a precise set of B(E2) transition probabilities in neutron-rich 74,76Zn isotopes. The resulting B(E2; 21+ → 01+) values are consistent with those determined in earlier REX-ISOLDE measurements. While the B(E2; 41+ → 21+) transition probability in 76Zn is also in agreement with earlier Coulomb-excitation results, the value obtained for 74Zn is considerably lower. For the first time, a spectroscopic quadrupole moment of the 21+ state was measured for an exotic nucleus in this mass region. A detailed comparison is presented with large-scale shell-model and Monte Carlo shell-model calculations.
Published: 2023

9. Lifetime measurements in the ground-state band in Pd-104

Author: Droste, M., Blazhev, A., Reiter, P., Arnswald, K., Beckers, M., Fransen, C., Hetzenegger, R., Hirsch, R., Kaya, L., Knafla, L., Lewandowski, L., Mueller-Gatermann, C., Petkov, P., Rosiak, D., Seidlitz, M., Siebeck, B., Vogt, A., Warr, N., Wolf, K., Droste, M., Blazhev, A., Reiter, P., Arnswald, K., Beckers, M., Fransen, C., Hetzenegger, R., Hirsch, R., Kaya, L., Knafla, L., Lewandowski, L., Mueller-Gatermann, C., Petkov, P., Rosiak, D., Seidlitz, M., Siebeck, B., Vogt, A., Warr, N., and Wolf, K.
Abstract: Lifetimes and reduced transition probabilities were determined in the ground-state band in Pd-104 up to the 12(+) state employing the recoil distance Doppler-shift method. Excited states were populated via the fusion-evaporation reaction Zr-96(C-12, 4n)Pd-104 at 55 MeV. The B(E2; 2(i)(+) -> O-g+s.(+)) value deviates from previous evaluated values obtained by Coulomb excitation and electron scattering. The transition strengths for higher-lying states were obtained for the first time, closing a gap in the medium-mass Pd isotope chain. Large-scale shell-model calculations were performed employing the SR88MHJM Hamiltonian along the isotope chain Pd96-106 for even-even nuclei and for high-spin states up to 26(+) in Pd-104.
Published: 2022

10. Coulomb excitation of Rn-222

Author: Spagnoletti, P., Butler, P. A., Gaffney, L. P., Abrahams, K., Bowry, M., Cederkall, J., Chupp, T., de Angelis, G., De Witte, H., Garrett, P. E., Goldkuhle, A., Henrich, C., Illana, A., Johnston, K., Joss, D. T., Keatings, J. M., Kelly, N. A., Komorowska, M., Konki, J., Kroll, T., Lozano, M., Singh, B. S. Nara, O'Donnell, D., Ojala, J., Page, R. D., Pedersen, L. G., Raison, C., Reiter, P., Rodriguez, J. A., Rosiak, D., Rothe, S., Scheck, M., Seidlitz, M., Shneidman, T. M., Siebeck, B., Sinclair, J., Smith, J. F., Stryjczyk, M., Van Duppen, P., Vinals, S., Virtanen, V., Wrzosek-Lipska, K., Warr, N., Zielinska, M., Spagnoletti, P., Butler, P. A., Gaffney, L. P., Abrahams, K., Bowry, M., Cederkall, J., Chupp, T., de Angelis, G., De Witte, H., Garrett, P. E., Goldkuhle, A., Henrich, C., Illana, A., Johnston, K., Joss, D. T., Keatings, J. M., Kelly, N. A., Komorowska, M., Konki, J., Kroll, T., Lozano, M., Singh, B. S. Nara, O'Donnell, D., Ojala, J., Page, R. D., Pedersen, L. G., Raison, C., Reiter, P., Rodriguez, J. A., Rosiak, D., Rothe, S., Scheck, M., Seidlitz, M., Shneidman, T. M., Siebeck, B., Sinclair, J., Smith, J. F., Stryjczyk, M., Van Duppen, P., Vinals, S., Virtanen, V., Wrzosek-Lipska, K., Warr, N., and Zielinska, M.
Abstract: The nature of quadrupole and octupole collectivity in 222Rn was investigated by determining the electricquadrupole (E2) and octupole (E3) matrix elements using subbarrier, multistep Coulomb excitation. The radioactive 222Rn beam, accelerated to 4.23 MeV/u, was provided by the HIE-ISOLDE facility at CERN. Data were collected in the Miniball gamma -ray spectrometer following the bombardment of two targets, 120Sn and 60Ni. Transition E2 matrix elements within the ground-state and octupole bands were measured up to 10 h over bar and the results were consistent with a constant intrinsic electric-quadrupole moment, 518(11) e fm2. The values of the intrinsic electric-octupole moment for the 0+ -> 3- and 2+ -> 5- transitions were found to be respectively -210 e fm3 and 2300+300-500 e fm3 while a smaller value, 1200+500-900 e fm3, was found for the 2+ -> 1- transition. In addition, four excited non-yrast states were identified in this work via gamma -gamma coincidences.
Published: 2022

11. Angular momentum generation in nuclear fission

Author: Wilson, J. N., Thisse, D., Lebois, M., Jovancevic, N., Gjestvang, D., Canavan, R., Rudigier, M., Etasse, D., Gerst, R-B, Gaudefroy, L., Adamska, E., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Courtin, S., Cortes, M. L., Davies, P., Delafosse, C., Fallot, M., Fornal, B., Fraile, L., Gottardo, A., Guadilla, V, Haefner, G., Hauschild, K., Heine, M., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Ivanov, P., Jazrawi, S., Korgul, A., Koseoglou, P., Kroell, T., Kurtukian-Nieto, T., Le Meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Lozeva, R., Matea, I, Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Rezynkina, K., Sanchez-Tembleque, V, Siem, S., Schmitt, C., Soderstrom, P-A, Surder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M., Zeiser, F., Ziliani, S., Wilson, J. N., Thisse, D., Lebois, M., Jovancevic, N., Gjestvang, D., Canavan, R., Rudigier, M., Etasse, D., Gerst, R-B, Gaudefroy, L., Adamska, E., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Courtin, S., Cortes, M. L., Davies, P., Delafosse, C., Fallot, M., Fornal, B., Fraile, L., Gottardo, A., Guadilla, V, Haefner, G., Hauschild, K., Heine, M., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Ivanov, P., Jazrawi, S., Korgul, A., Koseoglou, P., Kroell, T., Kurtukian-Nieto, T., Le Meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Lozeva, R., Matea, I, Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Rezynkina, K., Sanchez-Tembleque, V, Siem, S., Schmitt, C., Soderstrom, P-A, Surder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M., Zeiser, F., and Ziliani, S.
Abstract: When a heavy atomic nucleus splits (fission), the resulting fragments are observed to emerge spinning(1); this phenomenon has been a mystery in nuclear physics for over 40 years(2,3). The internal generation of typically six or seven units of angular momentum in each fragment is particularly puzzling for systems that start with zero, or almost zero, spin. There are currently no experimental observations that enable decisive discrimination between the many competing theories for the mechanism that generates the angular momentum(4-12). Nevertheless, the consensus is that excitation of collective vibrational modes generates the intrinsic spin before the nucleus splits (pre-scission). Here we show that there is no significant correlation between the spins of the fragment partners, which leads us to conclude that angular momentum in fission is actually generated after the nucleus splits (post-scission). We present comprehensive data showing that the average spin is strongly mass-dependent, varying in saw-tooth distributions. We observe no notable dependence of fragment spin on the mass or charge of the partner nucleus, confirming the uncorrelated post-scission nature of the spin mechanism. To explain these observations, we propose that the collective motion of nucleons in the ruptured neck of the fissioning system generates two independent torques, analogous to the snapping of an elastic band. A parameterization based on occupation of angular momentum states according to statistical theory describes the full range of experimental data well. This insight into the role of spin in nuclear fission is not only important for the fundamental understanding and theoretical description of fission, but also has consequences for the gamma-ray heating problem in nuclear reactors(13,14), for the study of the structure of neutron-rich isotopes(15,16), and for the synthesis and stability of super-heavy elements(17,18). gamma-ray spectroscopy experiments on the origin of spin in the prod
Published: 2021

12. First beta-decay spectroscopy of In-135 and new beta-decay branches of In-134

Author: Piersa-Silkowska, M., Korgul, A., Benito, J., Fraile, L. M., Adamska, E., Andreyev, A. N., Alvarez-Rodriguez, R., Barzakh, A. E., Benzoni, G., Berry, T., Borge, M. J. G., Carmona, M., Chrysalidis, K., Correia, J. G., Costache, C., Cubiss, J. G., Goodacre, T. Day, De Witte, H., Fedorov, D., V, Fedosseev, V. N., Fernandez-Martinez, G., Fijalkowska, A., Fynbo, H., Galaviz, D., Galve, P., Garcia-Diez, M., Greenlees, P. T., Grzywacz, R., Harkness-Brennan, L. J., Henrich, C., Huyse, M., Ibanez, P., Illana, A., Janas, Z., Johnston, K., Jolie, J., Judson, D. S., Karanyonchev, V, Kicinska-Habior, M., Konki, J., Koszuk, L., Kurcewicz, J., Lazarus, I, Lica, R., Lopez-Montes, A., Mach, H., Madurga, M., Marroquin, I, Marsh, B., Martinez, M. C., Mazzocchi, C., Miernik, K., Mihai, C., Marginean, N., Marginean, R., Negret, A., Nacher, E., Ojala, J., Olaizola, B., Page, R. D., Pakarinen, J., Pascu, S., Paulauskas, S., V, Perea, A., Pucknell, V, Rahkila, P., Raison, C., Rapisarda, E., Rezynkina, K., Rotaru, F., Rothe, S., Rykaczewski, K. P., Regis, J-M, Schomacker, K., Silkowski, M., Simpson, G., Sotty, C., Stan, L., Stanoiu, M., Stryjczyk, M., Sanchez-Parcerisa, D., Sanchez-Tembleque, V, Tengblad, O., Turturica, A., Udias, J. M., Van Duppen, P., Vedia, V., Villa, A., Vinals, S., Wadsworth, R., Walters, W. B., Warr, N., Wilkins, S. G., Piersa-Silkowska, M., Korgul, A., Benito, J., Fraile, L. M., Adamska, E., Andreyev, A. N., Alvarez-Rodriguez, R., Barzakh, A. E., Benzoni, G., Berry, T., Borge, M. J. G., Carmona, M., Chrysalidis, K., Correia, J. G., Costache, C., Cubiss, J. G., Goodacre, T. Day, De Witte, H., Fedorov, D., V, Fedosseev, V. N., Fernandez-Martinez, G., Fijalkowska, A., Fynbo, H., Galaviz, D., Galve, P., Garcia-Diez, M., Greenlees, P. T., Grzywacz, R., Harkness-Brennan, L. J., Henrich, C., Huyse, M., Ibanez, P., Illana, A., Janas, Z., Johnston, K., Jolie, J., Judson, D. S., Karanyonchev, V, Kicinska-Habior, M., Konki, J., Koszuk, L., Kurcewicz, J., Lazarus, I, Lica, R., Lopez-Montes, A., Mach, H., Madurga, M., Marroquin, I, Marsh, B., Martinez, M. C., Mazzocchi, C., Miernik, K., Mihai, C., Marginean, N., Marginean, R., Negret, A., Nacher, E., Ojala, J., Olaizola, B., Page, R. D., Pakarinen, J., Pascu, S., Paulauskas, S., V, Perea, A., Pucknell, V, Rahkila, P., Raison, C., Rapisarda, E., Rezynkina, K., Rotaru, F., Rothe, S., Rykaczewski, K. P., Regis, J-M, Schomacker, K., Silkowski, M., Simpson, G., Sotty, C., Stan, L., Stanoiu, M., Stryjczyk, M., Sanchez-Parcerisa, D., Sanchez-Tembleque, V, Tengblad, O., Turturica, A., Udias, J. M., Van Duppen, P., Vedia, V., Villa, A., Vinals, S., Wadsworth, R., Walters, W. B., Warr, N., and Wilkins, S. G.
Abstract: The beta decay of the neutron-rich In-134 and In-135 was investigated experimentally in order to provide new insights into the nuclear structure of the tin isotopes with magic proton number Z = 50 above the N = 82 shell. The beta-delayed gamma-ray spectroscopy measurement was performed at the ISOLDE facility at CERN, where indium isotopes were selectively laser-ionized and on-line mass separated. Three beta-decay branches of In-134 were established, two of which were observed for the first time. Population of neutron-unbound states decaying via. rays was identified in the two daughter nuclei of In-134, Sn-134 and Sn-133, at excitation energies exceeding the neutron separation energy by 1 MeV. The beta-delayed one- and two-neutron emission branching ratios of In-134 were determined and compared with theoretical calculations. The beta-delayed one-neutron decay was observed to be dominant beta-decay branch of In-134 even though the Gamow-Teller resonance is located substantially above the two-neutron separation energy of Sn-134. Transitions following the beta decay of In-135 are reported for the first time, including. rays tentatively attributed to Sn-135. In total, six new levels were identified in Sn-134 on the basis of the beta.. coincidences observed in the In-134 and In-135 beta decays. A transition that might be a candidate for deexciting the missing neutron single-particle 13/2(+) state in Sn-133 was observed in both beta decays and its assignment is discussed. Experimental level schemes of Sn-134 and Sn-135 are compared with shell-model predictions. Using the fast timing technique, half-lives of the 2(+), 4(+), and 6(+) levels in Sn-134 were determined. From the lifetime of the 4(+) state measured for the first time, an unexpectedly large B(E2; 4(+)-> 2(+)) transition strength was deduced, which is not reproduced by the shell-model calculations.
Published: 2021

13. New beta-decaying state in Bi-214

Author: Andel, B., Van Duppen, P., Andreyev, A. N., Blazhev, A., Grawe, H., Lica, R., Naidja, H., Stryjczyk, M., Algora, A., Antalic, S., Barzakh, A., Benito, J., Benzoni, G., Berry, T., Borge, M. J. G., Chrysalidis, K., Clisu, C., Costache, C., Cubiss, J. G., De Witte, H., Fedorov, D., V, Fedosseev, V. N., Fraile, L. M., Fynbo, H. O. U., Greenlees, P. T., Harkness-Brennan, L. J., Huyse, M., Illana, A., Jolie, J., Judson, D. S., Konki, J., Lazarus, I, Madurga, M., Marginean, N., Marginean, R., Mihai, C., Marsh, B. A., Molkanov, P., Mosat, P., Murias, J. R., Nacher, E., Negret, A., Page, R. D., Pascu, S., Perea, A., Pucknell, V, Rahkila, P., Rapisarda, E., Rezynkina, K., Sanchez-Tembleque, V, Schomacker, K., Seliverstov, M. D., Sotty, C., Stan, L., Surder, C., Tengblad, O., Vedia, V., Vinals, S., Wadsworth, R., Warr, N., Andel, B., Van Duppen, P., Andreyev, A. N., Blazhev, A., Grawe, H., Lica, R., Naidja, H., Stryjczyk, M., Algora, A., Antalic, S., Barzakh, A., Benito, J., Benzoni, G., Berry, T., Borge, M. J. G., Chrysalidis, K., Clisu, C., Costache, C., Cubiss, J. G., De Witte, H., Fedorov, D., V, Fedosseev, V. N., Fraile, L. M., Fynbo, H. O. U., Greenlees, P. T., Harkness-Brennan, L. J., Huyse, M., Illana, A., Jolie, J., Judson, D. S., Konki, J., Lazarus, I, Madurga, M., Marginean, N., Marginean, R., Mihai, C., Marsh, B. A., Molkanov, P., Mosat, P., Murias, J. R., Nacher, E., Negret, A., Page, R. D., Pascu, S., Perea, A., Pucknell, V, Rahkila, P., Rapisarda, E., Rezynkina, K., Sanchez-Tembleque, V, Schomacker, K., Seliverstov, M. D., Sotty, C., Stan, L., Surder, C., Tengblad, O., Vedia, V., Vinals, S., Wadsworth, R., and Warr, N.
Abstract: A new beta-decaying state in Bi-214 has been identified at the ISOLDE Decay Station at the CERN-ISOLDE facility. A preferred I-pi = (8(-)) assignment was suggested for this state based on the beta-decay feeding pattern to levels in Po-214 and shell-model calculations. The half-life of the I-pi = (8) state was deduced to be T-1/2 = 9.39(10) min. The deexcitation of the levels populated in Po-214 by the beta decay of this state was investigated via gamma-gamma coincidences and a number of new levels and transitions was identified. Shell-model calculations for excited states in Bi-214 and Po-214 were performed using two different effective interactions: the H208 and the modified Kuo-Herling particle interaction. Both calculations agree on the interpretation of the new beta-decaying state as an I-pi = 8 - isomer and allow for tentative assignment of shell-model states to several high-spin states in Po-214.
Published: 2021

14. Spectroscopy and lifetime measurements in Te-134,Te-136,Te-138 isotopes and implications for the nuclear structure beyond N=82

Author: Hafner, G., Lozeva, R., Naiedja, H., Lebois, M., Jovancevic, N., Thisse, D., Etasse, D., Canavan, R. L., Rudigier, M., Wilson, J. N., Adamska, E., Adsley, P., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Collins, S. M., Cortes, M. L., Davies, P. J., Delafosse, C., Fallot, M., Fornal, B., Fraile, L. M., Gerst, R-B, Gjestvang, D., Guadilla, V, Hauschild, K., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Jazwari, S., Jolie, J., Korgul, A., Koseoglou, P., Kroell, Th, Kurtukian-Nieto, T., Le-meur, L., Ljungvall, J., Lopez-Martens, A., Matea, I, Matthieu, L., Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Tello, D. Reygadas, Rezynkina, K., Sanchez, V, Schmitt, C., Soederstroem, P-A, Suerder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M. S., Zeiser, F., Ziliani, S., Hafner, G., Lozeva, R., Naiedja, H., Lebois, M., Jovancevic, N., Thisse, D., Etasse, D., Canavan, R. L., Rudigier, M., Wilson, J. N., Adamska, E., Adsley, P., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Collins, S. M., Cortes, M. L., Davies, P. J., Delafosse, C., Fallot, M., Fornal, B., Fraile, L. M., Gerst, R-B, Gjestvang, D., Guadilla, V, Hauschild, K., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Jazwari, S., Jolie, J., Korgul, A., Koseoglou, P., Kroell, Th, Kurtukian-Nieto, T., Le-meur, L., Ljungvall, J., Lopez-Martens, A., Matea, I, Matthieu, L., Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Tello, D. Reygadas, Rezynkina, K., Sanchez, V, Schmitt, C., Soederstroem, P-A, Suerder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M. S., Zeiser, F., and Ziliani, S.
Abstract: We report on spectroscopic information and lifetime measurements of even-even neutron-rich Te isotopes. Excited states were populated in fast-neutron induced fission of U-238 at the ALTO facility of IJCLab with the LICORNE neutron source and detected using the hybrid.-ball spectrometer. We provide first results on lifetimes of the 6(1)(+) state in Te-136 and the (6(1)(+)), (4(1)(+)), and (2(1)(+)) states in Te-138 and discuss the results in the context of large-scale shell-model calculations. The level schemes of Te-136 and Te-138 are revised in terms of lifetimes of their 2(1)(+), 4(1)(+) states and updated information on the (4(2)(+)) state in Te-136 is presented. In addition, previously reported data on spectroscopy and lifetimes in Te-134 are reexamined. This work provides new insights into the evolution of collectivity for Te isotopes with N = 82, 84, 86.
Published: 2021

15. First lifetime investigations of N > 82 iodine isotopes: The quest for collectivity

Author: Haefner, G., Lozeva, R., Naidja, H., Lebois, M., Jovancevic, N., Thisse, D., Etasse, D., Canavan, R. L., Rudigier, M., Wilson, J. N., Adamska, E., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Collins, S. M., Cortes, M. L., Davies, P. J., Delafosse, C., Fallot, M., Fraile, L. M., Gerst, R-B, Gjestvang, D., Guadilla, V, Hauschild, K., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Jazwari, S., Korgul, A., Koseoglou, P., Kroell, Th, Kurtukian-Nieto, T., Le-meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Matthieu, L., Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa-Silkowska, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Tello, D. Reygadas, Rezynkina, K., Sanchez-Tembleque, V, Schmitt, C., Soederstroem, P-A, Suerder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M. S., Zeiser, F., Ziliani, S., Haefner, G., Lozeva, R., Naidja, H., Lebois, M., Jovancevic, N., Thisse, D., Etasse, D., Canavan, R. L., Rudigier, M., Wilson, J. N., Adamska, E., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Collins, S. M., Cortes, M. L., Davies, P. J., Delafosse, C., Fallot, M., Fraile, L. M., Gerst, R-B, Gjestvang, D., Guadilla, V, Hauschild, K., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Jazwari, S., Korgul, A., Koseoglou, P., Kroell, Th, Kurtukian-Nieto, T., Le-meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Matthieu, L., Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa-Silkowska, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Tello, D. Reygadas, Rezynkina, K., Sanchez-Tembleque, V, Schmitt, C., Soederstroem, P-A, Suerder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M. S., Zeiser, F., and Ziliani, S.
Abstract: We report on spectroscopic information and lifetime measurements in the neutron-rich I-135,I-137,I-139 isotopes. This is the first lifetime data on iodine isotopes beyond N = 82. Excited states were populated in fast neutron-induced fission of U-238 at the ALTO facility of IJCLab with the LICORNE neutron source and detected using the hybrid nu-ball spectrometer. The level schemes of the I-135,I-137,I-139 isotopes are revised in terms of excited states with up to maximum spin-parity of (33/2(+)), populated for the first time in fast neutron-induced fission. We provide first results on the lifetimes of the (9/2(1)(+)) and (13/2(1)(+)) states in I-137 and I-139, and the (17/2(1)(+)) state in 137I. In addition, we give upper lifetime limits for the (11/2(1)(+)) states in I135-139, the (15/2(1)(+)) state in I-137, the (17/2(1)(+)) state in I-139, and reexamine the (29/2(1)(+)) state in I-137. The isomeric data in I-13(5) are reinvestigated, such as the previously known (15/2(1)(+)) and (23/21) isomers with T-1/2 of 1.64(14) and 4.6(7) ns, respectively, as obtained in this work. The new spectroscopic information is compared to that from spontaneous or thermal-neutron induced fission and discussed in the context of large scale shell-model (LSSM) calculations for the region beyond Sn-132, indicating the behavior of collectivity for the three valence-proton iodine chain with N = 82, 84, 86.
Published: 2021

16. Angular momentum generation in nuclear fission

Author: Wilson, J. N., Thisse, D., Lebois, M., Jovancevic, N., Gjestvang, D., Canavan, R., Rudigier, M., Etasse, D., Gerst, R-B, Gaudefroy, L., Adamska, E., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Courtin, S., Cortes, M. L., Davies, P., Delafosse, C., Fallot, M., Fornal, B., Fraile, L., Gottardo, A., Guadilla, V, Haefner, G., Hauschild, K., Heine, M., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Ivanov, P., Jazrawi, S., Korgul, A., Koseoglou, P., Kroell, T., Kurtukian-Nieto, T., Le Meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Lozeva, R., Matea, I, Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Rezynkina, K., Sanchez-Tembleque, V, Siem, S., Schmitt, C., Soderstrom, P-A, Surder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M., Zeiser, F., Ziliani, S., Wilson, J. N., Thisse, D., Lebois, M., Jovancevic, N., Gjestvang, D., Canavan, R., Rudigier, M., Etasse, D., Gerst, R-B, Gaudefroy, L., Adamska, E., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Courtin, S., Cortes, M. L., Davies, P., Delafosse, C., Fallot, M., Fornal, B., Fraile, L., Gottardo, A., Guadilla, V, Haefner, G., Hauschild, K., Heine, M., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Ivanov, P., Jazrawi, S., Korgul, A., Koseoglou, P., Kroell, T., Kurtukian-Nieto, T., Le Meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Lozeva, R., Matea, I, Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Rezynkina, K., Sanchez-Tembleque, V, Siem, S., Schmitt, C., Soderstrom, P-A, Surder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M., Zeiser, F., and Ziliani, S.
Abstract: When a heavy atomic nucleus splits (fission), the resulting fragments are observed to emerge spinning(1); this phenomenon has been a mystery in nuclear physics for over 40 years(2,3). The internal generation of typically six or seven units of angular momentum in each fragment is particularly puzzling for systems that start with zero, or almost zero, spin. There are currently no experimental observations that enable decisive discrimination between the many competing theories for the mechanism that generates the angular momentum(4-12). Nevertheless, the consensus is that excitation of collective vibrational modes generates the intrinsic spin before the nucleus splits (pre-scission). Here we show that there is no significant correlation between the spins of the fragment partners, which leads us to conclude that angular momentum in fission is actually generated after the nucleus splits (post-scission). We present comprehensive data showing that the average spin is strongly mass-dependent, varying in saw-tooth distributions. We observe no notable dependence of fragment spin on the mass or charge of the partner nucleus, confirming the uncorrelated post-scission nature of the spin mechanism. To explain these observations, we propose that the collective motion of nucleons in the ruptured neck of the fissioning system generates two independent torques, analogous to the snapping of an elastic band. A parameterization based on occupation of angular momentum states according to statistical theory describes the full range of experimental data well. This insight into the role of spin in nuclear fission is not only important for the fundamental understanding and theoretical description of fission, but also has consequences for the gamma-ray heating problem in nuclear reactors(13,14), for the study of the structure of neutron-rich isotopes(15,16), and for the synthesis and stability of super-heavy elements(17,18). gamma-ray spectroscopy experiments on the origin of spin in the prod
Published: 2021

17. First beta-decay spectroscopy of In-135 and new beta-decay branches of In-134

Author: Piersa-Silkowska, M., Korgul, A., Benito, J., Fraile, L. M., Adamska, E., Andreyev, A. N., Alvarez-Rodriguez, R., Barzakh, A. E., Benzoni, G., Berry, T., Borge, M. J. G., Carmona, M., Chrysalidis, K., Correia, J. G., Costache, C., Cubiss, J. G., Goodacre, T. Day, De Witte, H., Fedorov, D., V, Fedosseev, V. N., Fernandez-Martinez, G., Fijalkowska, A., Fynbo, H., Galaviz, D., Galve, P., Garcia-Diez, M., Greenlees, P. T., Grzywacz, R., Harkness-Brennan, L. J., Henrich, C., Huyse, M., Ibanez, P., Illana, A., Janas, Z., Johnston, K., Jolie, J., Judson, D. S., Karanyonchev, V, Kicinska-Habior, M., Konki, J., Koszuk, L., Kurcewicz, J., Lazarus, I, Lica, R., Lopez-Montes, A., Mach, H., Madurga, M., Marroquin, I, Marsh, B., Martinez, M. C., Mazzocchi, C., Miernik, K., Mihai, C., Marginean, N., Marginean, R., Negret, A., Nacher, E., Ojala, J., Olaizola, B., Page, R. D., Pakarinen, J., Pascu, S., Paulauskas, S., V, Perea, A., Pucknell, V, Rahkila, P., Raison, C., Rapisarda, E., Rezynkina, K., Rotaru, F., Rothe, S., Rykaczewski, K. P., Regis, J-M, Schomacker, K., Silkowski, M., Simpson, G., Sotty, C., Stan, L., Stanoiu, M., Stryjczyk, M., Sanchez-Parcerisa, D., Sanchez-Tembleque, V, Tengblad, O., Turturica, A., Udias, J. M., Van Duppen, P., Vedia, V., Villa, A., Vinals, S., Wadsworth, R., Walters, W. B., Warr, N., Wilkins, S. G., Piersa-Silkowska, M., Korgul, A., Benito, J., Fraile, L. M., Adamska, E., Andreyev, A. N., Alvarez-Rodriguez, R., Barzakh, A. E., Benzoni, G., Berry, T., Borge, M. J. G., Carmona, M., Chrysalidis, K., Correia, J. G., Costache, C., Cubiss, J. G., Goodacre, T. Day, De Witte, H., Fedorov, D., V, Fedosseev, V. N., Fernandez-Martinez, G., Fijalkowska, A., Fynbo, H., Galaviz, D., Galve, P., Garcia-Diez, M., Greenlees, P. T., Grzywacz, R., Harkness-Brennan, L. J., Henrich, C., Huyse, M., Ibanez, P., Illana, A., Janas, Z., Johnston, K., Jolie, J., Judson, D. S., Karanyonchev, V, Kicinska-Habior, M., Konki, J., Koszuk, L., Kurcewicz, J., Lazarus, I, Lica, R., Lopez-Montes, A., Mach, H., Madurga, M., Marroquin, I, Marsh, B., Martinez, M. C., Mazzocchi, C., Miernik, K., Mihai, C., Marginean, N., Marginean, R., Negret, A., Nacher, E., Ojala, J., Olaizola, B., Page, R. D., Pakarinen, J., Pascu, S., Paulauskas, S., V, Perea, A., Pucknell, V, Rahkila, P., Raison, C., Rapisarda, E., Rezynkina, K., Rotaru, F., Rothe, S., Rykaczewski, K. P., Regis, J-M, Schomacker, K., Silkowski, M., Simpson, G., Sotty, C., Stan, L., Stanoiu, M., Stryjczyk, M., Sanchez-Parcerisa, D., Sanchez-Tembleque, V, Tengblad, O., Turturica, A., Udias, J. M., Van Duppen, P., Vedia, V., Villa, A., Vinals, S., Wadsworth, R., Walters, W. B., Warr, N., and Wilkins, S. G.
Abstract: The beta decay of the neutron-rich In-134 and In-135 was investigated experimentally in order to provide new insights into the nuclear structure of the tin isotopes with magic proton number Z = 50 above the N = 82 shell. The beta-delayed gamma-ray spectroscopy measurement was performed at the ISOLDE facility at CERN, where indium isotopes were selectively laser-ionized and on-line mass separated. Three beta-decay branches of In-134 were established, two of which were observed for the first time. Population of neutron-unbound states decaying via. rays was identified in the two daughter nuclei of In-134, Sn-134 and Sn-133, at excitation energies exceeding the neutron separation energy by 1 MeV. The beta-delayed one- and two-neutron emission branching ratios of In-134 were determined and compared with theoretical calculations. The beta-delayed one-neutron decay was observed to be dominant beta-decay branch of In-134 even though the Gamow-Teller resonance is located substantially above the two-neutron separation energy of Sn-134. Transitions following the beta decay of In-135 are reported for the first time, including. rays tentatively attributed to Sn-135. In total, six new levels were identified in Sn-134 on the basis of the beta.. coincidences observed in the In-134 and In-135 beta decays. A transition that might be a candidate for deexciting the missing neutron single-particle 13/2(+) state in Sn-133 was observed in both beta decays and its assignment is discussed. Experimental level schemes of Sn-134 and Sn-135 are compared with shell-model predictions. Using the fast timing technique, half-lives of the 2(+), 4(+), and 6(+) levels in Sn-134 were determined. From the lifetime of the 4(+) state measured for the first time, an unexpectedly large B(E2; 4(+)-> 2(+)) transition strength was deduced, which is not reproduced by the shell-model calculations.
Published: 2021

18. First lifetime investigations of N > 82 iodine isotopes: The quest for collectivity

Author: Haefner, G., Lozeva, R., Naidja, H., Lebois, M., Jovancevic, N., Thisse, D., Etasse, D., Canavan, R. L., Rudigier, M., Wilson, J. N., Adamska, E., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Collins, S. M., Cortes, M. L., Davies, P. J., Delafosse, C., Fallot, M., Fraile, L. M., Gerst, R-B, Gjestvang, D., Guadilla, V, Hauschild, K., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Jazwari, S., Korgul, A., Koseoglou, P., Kroell, Th, Kurtukian-Nieto, T., Le-meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Matthieu, L., Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa-Silkowska, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Tello, D. Reygadas, Rezynkina, K., Sanchez-Tembleque, V, Schmitt, C., Soederstroem, P-A, Suerder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M. S., Zeiser, F., Ziliani, S., Haefner, G., Lozeva, R., Naidja, H., Lebois, M., Jovancevic, N., Thisse, D., Etasse, D., Canavan, R. L., Rudigier, M., Wilson, J. N., Adamska, E., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Collins, S. M., Cortes, M. L., Davies, P. J., Delafosse, C., Fallot, M., Fraile, L. M., Gerst, R-B, Gjestvang, D., Guadilla, V, Hauschild, K., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Jazwari, S., Korgul, A., Koseoglou, P., Kroell, Th, Kurtukian-Nieto, T., Le-meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Matthieu, L., Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa-Silkowska, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Tello, D. Reygadas, Rezynkina, K., Sanchez-Tembleque, V, Schmitt, C., Soederstroem, P-A, Suerder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M. S., Zeiser, F., and Ziliani, S.
Abstract: We report on spectroscopic information and lifetime measurements in the neutron-rich I-135,I-137,I-139 isotopes. This is the first lifetime data on iodine isotopes beyond N = 82. Excited states were populated in fast neutron-induced fission of U-238 at the ALTO facility of IJCLab with the LICORNE neutron source and detected using the hybrid nu-ball spectrometer. The level schemes of the I-135,I-137,I-139 isotopes are revised in terms of excited states with up to maximum spin-parity of (33/2(+)), populated for the first time in fast neutron-induced fission. We provide first results on the lifetimes of the (9/2(1)(+)) and (13/2(1)(+)) states in I-137 and I-139, and the (17/2(1)(+)) state in 137I. In addition, we give upper lifetime limits for the (11/2(1)(+)) states in I135-139, the (15/2(1)(+)) state in I-137, the (17/2(1)(+)) state in I-139, and reexamine the (29/2(1)(+)) state in I-137. The isomeric data in I-13(5) are reinvestigated, such as the previously known (15/2(1)(+)) and (23/21) isomers with T-1/2 of 1.64(14) and 4.6(7) ns, respectively, as obtained in this work. The new spectroscopic information is compared to that from spontaneous or thermal-neutron induced fission and discussed in the context of large scale shell-model (LSSM) calculations for the region beyond Sn-132, indicating the behavior of collectivity for the three valence-proton iodine chain with N = 82, 84, 86.
Published: 2021

19. Spectroscopy and lifetime measurements in Te-134,Te-136,Te-138 isotopes and implications for the nuclear structure beyond N=82

Author: Hafner, G., Lozeva, R., Naiedja, H., Lebois, M., Jovancevic, N., Thisse, D., Etasse, D., Canavan, R. L., Rudigier, M., Wilson, J. N., Adamska, E., Adsley, P., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Collins, S. M., Cortes, M. L., Davies, P. J., Delafosse, C., Fallot, M., Fornal, B., Fraile, L. M., Gerst, R-B, Gjestvang, D., Guadilla, V, Hauschild, K., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Jazwari, S., Jolie, J., Korgul, A., Koseoglou, P., Kroell, Th, Kurtukian-Nieto, T., Le-meur, L., Ljungvall, J., Lopez-Martens, A., Matea, I, Matthieu, L., Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Tello, D. Reygadas, Rezynkina, K., Sanchez, V, Schmitt, C., Soederstroem, P-A, Suerder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M. S., Zeiser, F., Ziliani, S., Hafner, G., Lozeva, R., Naiedja, H., Lebois, M., Jovancevic, N., Thisse, D., Etasse, D., Canavan, R. L., Rudigier, M., Wilson, J. N., Adamska, E., Adsley, P., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Blazhev, A., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Collins, S. M., Cortes, M. L., Davies, P. J., Delafosse, C., Fallot, M., Fornal, B., Fraile, L. M., Gerst, R-B, Gjestvang, D., Guadilla, V, Hauschild, K., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Jazwari, S., Jolie, J., Korgul, A., Koseoglou, P., Kroell, Th, Kurtukian-Nieto, T., Le-meur, L., Ljungvall, J., Lopez-Martens, A., Matea, I, Matthieu, L., Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Tello, D. Reygadas, Rezynkina, K., Sanchez, V, Schmitt, C., Soederstroem, P-A, Suerder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M. S., Zeiser, F., and Ziliani, S.
Abstract: We report on spectroscopic information and lifetime measurements of even-even neutron-rich Te isotopes. Excited states were populated in fast-neutron induced fission of U-238 at the ALTO facility of IJCLab with the LICORNE neutron source and detected using the hybrid.-ball spectrometer. We provide first results on lifetimes of the 6(1)(+) state in Te-136 and the (6(1)(+)), (4(1)(+)), and (2(1)(+)) states in Te-138 and discuss the results in the context of large-scale shell-model calculations. The level schemes of Te-136 and Te-138 are revised in terms of lifetimes of their 2(1)(+), 4(1)(+) states and updated information on the (4(2)(+)) state in Te-136 is presented. In addition, previously reported data on spectroscopy and lifetimes in Te-134 are reexamined. This work provides new insights into the evolution of collectivity for Te isotopes with N = 82, 84, 86.
Published: 2021

20. New beta-decaying state in Bi-214

Author: Andel, B., Van Duppen, P., Andreyev, A. N., Blazhev, A., Grawe, H., Lica, R., Naidja, H., Stryjczyk, M., Algora, A., Antalic, S., Barzakh, A., Benito, J., Benzoni, G., Berry, T., Borge, M. J. G., Chrysalidis, K., Clisu, C., Costache, C., Cubiss, J. G., De Witte, H., Fedorov, D., V, Fedosseev, V. N., Fraile, L. M., Fynbo, H. O. U., Greenlees, P. T., Harkness-Brennan, L. J., Huyse, M., Illana, A., Jolie, J., Judson, D. S., Konki, J., Lazarus, I, Madurga, M., Marginean, N., Marginean, R., Mihai, C., Marsh, B. A., Molkanov, P., Mosat, P., Murias, J. R., Nacher, E., Negret, A., Page, R. D., Pascu, S., Perea, A., Pucknell, V, Rahkila, P., Rapisarda, E., Rezynkina, K., Sanchez-Tembleque, V, Schomacker, K., Seliverstov, M. D., Sotty, C., Stan, L., Surder, C., Tengblad, O., Vedia, V., Vinals, S., Wadsworth, R., Warr, N., Andel, B., Van Duppen, P., Andreyev, A. N., Blazhev, A., Grawe, H., Lica, R., Naidja, H., Stryjczyk, M., Algora, A., Antalic, S., Barzakh, A., Benito, J., Benzoni, G., Berry, T., Borge, M. J. G., Chrysalidis, K., Clisu, C., Costache, C., Cubiss, J. G., De Witte, H., Fedorov, D., V, Fedosseev, V. N., Fraile, L. M., Fynbo, H. O. U., Greenlees, P. T., Harkness-Brennan, L. J., Huyse, M., Illana, A., Jolie, J., Judson, D. S., Konki, J., Lazarus, I, Madurga, M., Marginean, N., Marginean, R., Mihai, C., Marsh, B. A., Molkanov, P., Mosat, P., Murias, J. R., Nacher, E., Negret, A., Page, R. D., Pascu, S., Perea, A., Pucknell, V, Rahkila, P., Rapisarda, E., Rezynkina, K., Sanchez-Tembleque, V, Schomacker, K., Seliverstov, M. D., Sotty, C., Stan, L., Surder, C., Tengblad, O., Vedia, V., Vinals, S., Wadsworth, R., and Warr, N.
Abstract: A new beta-decaying state in Bi-214 has been identified at the ISOLDE Decay Station at the CERN-ISOLDE facility. A preferred I-pi = (8(-)) assignment was suggested for this state based on the beta-decay feeding pattern to levels in Po-214 and shell-model calculations. The half-life of the I-pi = (8) state was deduced to be T-1/2 = 9.39(10) min. The deexcitation of the levels populated in Po-214 by the beta decay of this state was investigated via gamma-gamma coincidences and a number of new levels and transitions was identified. Shell-model calculations for excited states in Bi-214 and Po-214 were performed using two different effective interactions: the H208 and the modified Kuo-Herling particle interaction. Both calculations agree on the interpretation of the new beta-decaying state as an I-pi = 8 - isomer and allow for tentative assignment of shell-model states to several high-spin states in Po-214.
Published: 2021

21. First -decay spectroscopy of and new -decay branches of

Author: National Science Centre (Poland), Universidad Complutense de Madrid, Agencia Estatal de Investigación (España), Science and Technology Facilities Council (UK), Federal Ministry of Education and Research (Germany), Fundação para a Ciência e a Tecnologia (Portugal), European Organization for Nuclear Research, Institute of Atomic Physics (Romania), European Commission, Academy of Finland, York University, Piersa-Siłkowska, M., Korgul, A., Benito, J., Fraile, Luis M., Benzoni, G., Berry, T., García Borge, María José, Carmona, M., Chrysalidis, K., Correia, J.G., Costache, C., Cubiss, J.G., Day Goodacre, T., De Witte, H., Fedorov, D.V., Fedosseev, V.N., Fernández-Martínez, G., Fynbo, H.O.U., Galaviz, D., Galve, P., García-Díez, M., Greenlees, P.T., Grzywacz, R., Harkness-Brennan, L.J., Henrich, C., Huyse, M., Ibáñez, P., Illana, A., Janas, Z., Johnston, K., Jolie, J., Judson, D.S., Karanyonchev, V., Kicinska-Habior, M., Konki, J., Koszuk, L., Kurcewicz, J., Lazarus, I., Lică, R., López-Montes, A., Mach, H., Madurga, M., Marroquín, I., Marsh, B., Martínez Rodríguez, María del Carmen, Nácher, Enrique, Olaizola, B., Page, R.D., Perea, Ángel, Pucknell, V., Rykaczewski, K.P., Régis, J.M., Schomacker, K., Sánchez-Parcerisa, D., Sánchez-Tembleque, V., Tengblad, Olof, Udías, J.M., Vedia, V., Villa, A., Viñals, S., Warr, N., National Science Centre (Poland), Universidad Complutense de Madrid, Agencia Estatal de Investigación (España), Science and Technology Facilities Council (UK), Federal Ministry of Education and Research (Germany), Fundação para a Ciência e a Tecnologia (Portugal), European Organization for Nuclear Research, Institute of Atomic Physics (Romania), European Commission, Academy of Finland, York University, Piersa-Siłkowska, M., Korgul, A., Benito, J., Fraile, Luis M., Benzoni, G., Berry, T., García Borge, María José, Carmona, M., Chrysalidis, K., Correia, J.G., Costache, C., Cubiss, J.G., Day Goodacre, T., De Witte, H., Fedorov, D.V., Fedosseev, V.N., Fernández-Martínez, G., Fynbo, H.O.U., Galaviz, D., Galve, P., García-Díez, M., Greenlees, P.T., Grzywacz, R., Harkness-Brennan, L.J., Henrich, C., Huyse, M., Ibáñez, P., Illana, A., Janas, Z., Johnston, K., Jolie, J., Judson, D.S., Karanyonchev, V., Kicinska-Habior, M., Konki, J., Koszuk, L., Kurcewicz, J., Lazarus, I., Lică, R., López-Montes, A., Mach, H., Madurga, M., Marroquín, I., Marsh, B., Martínez Rodríguez, María del Carmen, Nácher, Enrique, Olaizola, B., Page, R.D., Perea, Ángel, Pucknell, V., Rykaczewski, K.P., Régis, J.M., Schomacker, K., Sánchez-Parcerisa, D., Sánchez-Tembleque, V., Tengblad, Olof, Udías, J.M., Vedia, V., Villa, A., Viñals, S., and Warr, N.
Abstract: The decay of the neutron-rich and was investigated experimentally in order to provide new insights into the nuclear structure of the tin isotopes with magic proton number above the shell. The -delayed -ray spectroscopy measurement was performed at the ISOLDE facility at CERN, where indium isotopes were selectively laser-ionized and on-line mass separated. Three -decay branches of were established, two of which were observed for the first time. Population of neutron-unbound states decaying via rays was identified in the two daughter nuclei of and , at excitation energies exceeding the neutron separation energy by 1 MeV. The -delayed one- and two-neutron emission branching ratios of were determined and compared with theoretical calculations. The -delayed one-neutron decay was observed to be dominant -decay branch of even though the Gamow-Teller resonance is located substantially above the two-neutron separation energy of . Transitions following the decay of are reported for the first time, including rays tentatively attributed to . In total, six new levels were identified in on the basis of the coincidences observed in the and decays. A transition that might be a candidate for deexciting the missing neutron single-particle state in was observed in both decays and its assignment is discussed. Experimental level schemes of and are compared with shell-model predictions. Using the fast timing technique, half-lives of the , and levels in were determined. From the lifetime of the state measured for the first time, an unexpectedly large transition strength was deduced, which is not reproduced by the shell-model calculations.
Published: 2021

22. Population of lead isotopes in binary reactions using a Rb-94 radioactive beam

Author: European Commission, Science and Technology Facilities Council (UK), Croatian Science Foundation, Federal Ministry of Education and Research (Germany), Colovic, P., Szilner, S., Illana, A., Valiente-Dobón, J.J., Corradi, L., Pollarolo, G., Mijatovic, T., Goasduff, A., Benzoni, G., García Borge, María José, Boso, A., Boukhari, A., Ceruti, S., Cubiss, J.G., Angelis, G. de, Witte, H. de, Fioretto, E., Fransen, Ch., Galtarossa, F., Gaffney, L.P., Giannopoulos, E., Hess, H., Jurado-Gómez, M.L., Kaya, L., Kröll, Th., Marchi, T., Menegazzo, R., Mengoni, D., Napoli, D.R., O'Neill, G., Pakarinen, J., Podolyák, Zs., Recchia, F., Reiter, P., Rosiak, D., Snall, J., Spagnoletti, P., Testov, D., Thiel, S., Warr, N., Zidarova, R., European Commission, Science and Technology Facilities Council (UK), Croatian Science Foundation, Federal Ministry of Education and Research (Germany), Colovic, P., Szilner, S., Illana, A., Valiente-Dobón, J.J., Corradi, L., Pollarolo, G., Mijatovic, T., Goasduff, A., Benzoni, G., García Borge, María José, Boso, A., Boukhari, A., Ceruti, S., Cubiss, J.G., Angelis, G. de, Witte, H. de, Fioretto, E., Fransen, Ch., Galtarossa, F., Gaffney, L.P., Giannopoulos, E., Hess, H., Jurado-Gómez, M.L., Kaya, L., Kröll, Th., Marchi, T., Menegazzo, R., Mengoni, D., Napoli, D.R., O'Neill, G., Pakarinen, J., Podolyák, Zs., Recchia, F., Reiter, P., Rosiak, D., Snall, J., Spagnoletti, P., Testov, D., Thiel, S., Warr, N., and Zidarova, R.
Abstract: We measured absolute cross sections for neutron transfer channels populated in the Rb-94 + Pb-208 binary reaction. Cross sections have been extracted identifying directly the lead isotopes with the high efficiency MINIBALL gamma-ray array coupled to a particle detector combined with a radioactive Rb-94 beam delivered at E-lab = 6.2 MeV/nucleon by the HIE-ISOLDE facility. We observed sizable cross sections in the neutron-rich mass region, where the heavy partner acquires neutrons. A fair agreement between the measured cross sections with those from GRAZING calculations gives confidence in the cross-section predictions of more neutron-rich nuclei produced via a larger number of transferred nucleons.
Published: 2020

23. gamma-RAY SPECTROSCOPY OF Se-85 PRODUCED IN Th-232 FISSION

Author: Adamska, E., Korgul, A., Fijalkowska, A., Miernik, K., Piersa, M., Canavan, R., Etasse, D., Jovancevic, N., Lebois, M., Rudigier, M., Thisse, D., Wilson, J. N., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Blazhev, A., Benzoni, G., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Ciemala, M., Collins, S., Cortes, L., Davies, P., Delafosse, C., Fallot, M., Fornal, B., Fraile, L. M., Gerst, R. -B., Gjestvang, D., Gottardo, A., Guadilla, V., Hafner, G., Hauschild, K., Heine, M., Henrich, C., Homm, I., Ibrahim, F., Iskra, L. W., Koseoglou, P., Kroell, T., Kurtukian-Nieto, T., Le-Meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Lozeva, R., Matea, I., Nemer, J., Oberstedt, S., Paulsen, W., Popovitch, Y., Qi, L., Ralet, D., Regan, P. H., Tello, D. Reygadas, Rezynkina, K., Sanchez-Tembleque, V., Schmitt, C., Soederstroem, P. -A., Surder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M., Zeiser, F., Adamska, E., Korgul, A., Fijalkowska, A., Miernik, K., Piersa, M., Canavan, R., Etasse, D., Jovancevic, N., Lebois, M., Rudigier, M., Thisse, D., Wilson, J. N., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Blazhev, A., Benzoni, G., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Ciemala, M., Collins, S., Cortes, L., Davies, P., Delafosse, C., Fallot, M., Fornal, B., Fraile, L. M., Gerst, R. -B., Gjestvang, D., Gottardo, A., Guadilla, V., Hafner, G., Hauschild, K., Heine, M., Henrich, C., Homm, I., Ibrahim, F., Iskra, L. W., Koseoglou, P., Kroell, T., Kurtukian-Nieto, T., Le-Meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Lozeva, R., Matea, I., Nemer, J., Oberstedt, S., Paulsen, W., Popovitch, Y., Qi, L., Ralet, D., Regan, P. H., Tello, D. Reygadas, Rezynkina, K., Sanchez-Tembleque, V., Schmitt, C., Soederstroem, P. -A., Surder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M., and Zeiser, F.
Abstract: Excited states in the neutron-rich Se-85 nucleus have been studied using for the first time a fast neutron-induced fission of Th-232. The experiment was performed at the ALTO facility of the IPN Orsay. Coupling of the LICORNE directional neutron source with the nu-ball high-resolution gamma-ray spectrometer provided unique access to high-spin states in neutron-rich fission fragments from the Th-232(n,f) reaction. A preliminary level scheme of Se-85 was established by the analysis of prompt gamma-gamma-gamma coincidences. Identification of the all known yrast states in Se-85 is the first step towards studies of more neutron-rich Se isotopes.
Published: 2020

24. Search for proton emission of the isomeric 10(+) state in Ni-54

Author: Stahl, K., Wendt, A., Reiter, P., Rudolph, D., Blazhev, A., Bruyneel, B., Eberth, J., Fahlander, C., Fransen, C., Golubev, P., Hess, H., Hoischen, R., Holler, A., Kalkuehler, M., Kotthaus, T., Lersch, D., Pascovici, G., Seidlitz, M., Siebeck, B., Taprogge, J., Warr, N., Wiens, A., Zell, O., Stahl, K., Wendt, A., Reiter, P., Rudolph, D., Blazhev, A., Bruyneel, B., Eberth, J., Fahlander, C., Fransen, C., Golubev, P., Hess, H., Hoischen, R., Holler, A., Kalkuehler, M., Kotthaus, T., Lersch, D., Pascovici, G., Seidlitz, M., Siebeck, B., Taprogge, J., Warr, N., Wiens, A., and Zell, O.
Abstract: Several experiments were conducted at the 10 MV Van-de-Graaff tandem accelerator at the Institute of Nuclear Physics, Cologne, to detect proton emission from the isomeric 6457-keV 10(+) state in Ni-54. Excitation functions for two fusion-evaporation reactions were measured to maximise the population of the rare two-neutron evaporation channel from a Ni-56 compound nucleus. The search for delayed proton emission was based on the Si-28(Si-28, 2n)Ni-54 reaction at a beam energy of 70 MeV. For this reaction, a cross-section limit for the population of the 10(+) state in Ni-54 and its proton-decay branch was determined to be sigma < 22 nb.
Published: 2020

25. Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive Ra-222 and Ra-228 Beams

Author: Butler, P. A., Gaffney, L. P., Spagnoletti, P., Abrahams, K., Bowry, M., Cederkall, J., de Angelis, G., De Witte, H., Garrett, P. E., Goldkuhle, A., Henrich, C., Illana, A., Johnston, K., Joss, D. T., Keatings, J. M., Kelly, N. A., Komorowska, M., Konki, J., Kroell, T., Lozano, M., Singh, B. S. Nara, O'Donnell, D., Ojala, J., Page, R. D., Pedersen, L. G., Raison, C., Reiter, P., Rodriguez, J. A., Rosiak, D., Rothe, S., Scheck, M., Seidlitz, M., Shneidman, T. M., Siebeck, B., Sinclair, J., Smith, J. F., Stryjczyk, M., Van Duppen, P., Vinals, S., Virtanen, V., Warr, N., Wrzosek-Lipska, K., Zielinska, M., Butler, P. A., Gaffney, L. P., Spagnoletti, P., Abrahams, K., Bowry, M., Cederkall, J., de Angelis, G., De Witte, H., Garrett, P. E., Goldkuhle, A., Henrich, C., Illana, A., Johnston, K., Joss, D. T., Keatings, J. M., Kelly, N. A., Komorowska, M., Konki, J., Kroell, T., Lozano, M., Singh, B. S. Nara, O'Donnell, D., Ojala, J., Page, R. D., Pedersen, L. G., Raison, C., Reiter, P., Rodriguez, J. A., Rosiak, D., Rothe, S., Scheck, M., Seidlitz, M., Shneidman, T. M., Siebeck, B., Sinclair, J., Smith, J. F., Stryjczyk, M., Van Duppen, P., Vinals, S., Virtanen, V., Warr, N., Wrzosek-Lipska, K., and Zielinska, M.
Abstract: There is sparse direct experimental evidence that atomic nuclei can exhibit stable pear shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole (E3) matrix elements have been determined for transitions in Ra-222,Ra-228 nuclei using the method of sub-barrier, multistep Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of E3 matrix elements for different nuclear transitions is explained by describing Ra-222 as pear shaped with stable octupole deformation, while Ra-228 behaves like an octupole vibrator.
Published: 2020

26. Shape coexistence and multiparticle-multihole structures in Cd-110,Cd-112

Author: Garrett, P. E., Rodriguez, T. R., Varela, A. Diaz, Green, K. L., Bangay, J., Finlay, A., Austin, R. A. E., Ball, G. C., Bandyopadhyay, D. S., Bildstein, V, Colosimo, S., Cross, D. S., Demand, G. A., Finlay, P., Garnsworthy, A. B., Grinyer, G. F., Hackman, G., Jigmeddorj, B., Jolie, J., Kulp, W. D., Leach, K. G., Morton, A. C., Orce, J. N., Pearson, C. J., Phillips, A. A., Radich, A. J., Rand, E. T., Schumaker, M. A., Svensson, C. E., Sumithrarachchi, C., Triambak, S., Warr, N., Wong, J., Wood, J. L., Yates, S. W., Garrett, P. E., Rodriguez, T. R., Varela, A. Diaz, Green, K. L., Bangay, J., Finlay, A., Austin, R. A. E., Ball, G. C., Bandyopadhyay, D. S., Bildstein, V, Colosimo, S., Cross, D. S., Demand, G. A., Finlay, P., Garnsworthy, A. B., Grinyer, G. F., Hackman, G., Jigmeddorj, B., Jolie, J., Kulp, W. D., Leach, K. G., Morton, A. C., Orce, J. N., Pearson, C. J., Phillips, A. A., Radich, A. J., Rand, E. T., Schumaker, M. A., Svensson, C. E., Sumithrarachchi, C., Triambak, S., Warr, N., Wong, J., Wood, J. L., and Yates, S. W.
Abstract: From detailed spectroscopy of Cd-110 and Cd-112 following the beta(+)/EC decay of In-110,In-112 and the beta(-) decay of Ag-112, the presence of very weak decay branches from nonyrast states is revealed. In Cd-112, 2(5)(+) -> 0(4)(+) and 4(6)(+) -> 2(5)(+) transitions are observed that yield B(E2; 2(5)(+) -> 0(4)(+)) = 34 +/- 15 W.u. and B(E2; 4(6)(+) -> 2(5)(+)) = 77 +/- 30 W.u., respectively, clearly indicating a collective structure. In 110Cd, a weak decay branch from the 4(6)(+) level to the 2(5)(+) level is observed, and from a lifetime measurement following the (n, n gamma' reaction, B(E2; 4(6)(+) -> 2(5)(+)) = 55 +/- 14 W.u. is determined. A new branch is also observed for the decay of the 6(4)(+) level to the 4(6)(+) state, indicating that the sequence 2(5)(+), 4(6)(+), and 6(4)(+) forms part of a collective structure. The presence of 3(3)(+) and 5(2)(+) levels spaced between the previous sequence is highly suggestive of a gamma band built on the 0(2)(+) shape-coexisting intruder state. The 0(4)(+) levels in Cd-110,Cd-112,Cd-114 have preferred decays to the lowest 2(+) members of the intruder bands, and for 114Cd a previous measurement had established an enhanced B(E2; 0(4)(+) -> 2(3)(+)). The energy systematics of the 0(2)(+), 0(3)(+), and 0(4)(+) levels all display the characteristic parabolic-shaped pattern, suggesting that they are built on multiparticle-multihole proton excitations. The results are compared with beyond-mean-field calculations that reproduce qualitatively the observed levels and their decays and suggest that the 0(1)(+), 0(2)(+), 0(3)(+), and 0(4)(+) levels and the excited states built on them possess different deformations.
Published: 2020

27. Octupole states in Tl-207 studied through beta decay

Author: Berry, T. A., Podolyak, Zs, Carroll, R. J., Lica, R., Brown, B. A., Grawe, H., Sotty, Ch, Timofeyuk, N. K., Alexander, T., Andreyev, A. N., Ansari, S., Borge, M. J. G., Brunet, M., Cresswell, J. R., Fahlander, C., Fraile, L. M., Fynbo, H. O. U., Gamba, E., Gelletly, W., Gerst, R-B, Gorska, M., Gredley, A., Greenlees, P., Harkness-Brennan, L. J., Huyse, M., Judge, S. M., Judson, D. S., Konki, J., Kowalska, M., Kurcewicz, J., Kuti, I, Lalkovski, S., Lazarus, I, Lund, M., Madurga, M., Marginean, N., Mihai, C., Mihai, R. E., Nacher, E., Negret, A., Nae, S., Nita, C., Pascu, S., Page, R. D., Patel, Z., Perea, A., Phrompao, J., Piersa, M., Pucknell, V, Rahkila, P., Rapisarda, E., Regan, P. H., Rotaru, F., Rudigier, M., Shand, C. M., Shearman, R., Simpson, E. C., Stegemann, S., Stora, T., Tengblad, O., Turturica, A., Van Duppen, P., Vedia, V., Walker, P. M., Warr, N., Wearing, F. P., De Witte, H., Berry, T. A., Podolyak, Zs, Carroll, R. J., Lica, R., Brown, B. A., Grawe, H., Sotty, Ch, Timofeyuk, N. K., Alexander, T., Andreyev, A. N., Ansari, S., Borge, M. J. G., Brunet, M., Cresswell, J. R., Fahlander, C., Fraile, L. M., Fynbo, H. O. U., Gamba, E., Gelletly, W., Gerst, R-B, Gorska, M., Gredley, A., Greenlees, P., Harkness-Brennan, L. J., Huyse, M., Judge, S. M., Judson, D. S., Konki, J., Kowalska, M., Kurcewicz, J., Kuti, I, Lalkovski, S., Lazarus, I, Lund, M., Madurga, M., Marginean, N., Mihai, C., Mihai, R. E., Nacher, E., Negret, A., Nae, S., Nita, C., Pascu, S., Page, R. D., Patel, Z., Perea, A., Phrompao, J., Piersa, M., Pucknell, V, Rahkila, P., Rapisarda, E., Regan, P. H., Rotaru, F., Rudigier, M., Shand, C. M., Shearman, R., Simpson, E. C., Stegemann, S., Stora, T., Tengblad, O., Turturica, A., Van Duppen, P., Vedia, V., Walker, P. M., Warr, N., Wearing, F. P., and De Witte, H.
Abstract: The beta decay of Hg-207 into the single-proton-hole nucleus Tl-207 has been studied through gamma-ray spectroscopy at the ISOLDE Decay Station (IDS) with the aim of identifying states resulting from coupling of the pi s(1/2)(-1), pi d(3/2)(-1) and pi h(11/2)(-1) shell model orbitals to the collective octupole vibration. Twenty-two states were observed lying between 2.6 and 4.0 MeV, eleven of which were observed for the first time, and 78 new transitions were placed. Two octupole states (s(3/2)-coupled) are identified and three more states (d(3/2)-coupled) are tentatively assigned using spin-parity inferences, while further h(11/2)-coupled states may also have been observed for the first time. Comparisons are made with state-of-the-art large-scale shell model calculations and previous observations made in this region, and systematic underestimation of the energy of the octupole vibrational states is noted. We suggest that in order to resolve the difference in predicted energies for collective and noncollective t = 1 states (t is the number of nucleons breaking the Pb-208 core), the effect of t = 2 mixing may be reduced for octupole-coupled states. The inclusion of mixing with t = 0, 2, 3 excitations is necessary to replicate all t = 1 state energies accurately.
Published: 2020

28. Nuclear structure studies with re-accelerated beams at REX-and HIE-ISOLDE

Author: Reiter, P., Warr, N., Reiter, P., and Warr, N.
Abstract: Nuclear-structure studies with reaccelerated radioactive ion beams at the ISOLDE facility, CERN commenced with the REX-ISOLDE facility and continued after a major upgrade of the facility with the HIE-ISOLDE post-accelerator. The experiments are based on in-beam high-resolution gamma-ray spectroscopy with Miniball, a spectrometer which comprises 24 six-fold segmented, encapsulated high-purity germanium crystals. The Miniball array has been used in Coulomb excitation and transfer-reaction experiments with exotic ion beams of energies up to 10 MeV/u. The investigations cover a wide range of nuclear structure topics which are addressed with beams ranging from beryllium up to heavy radium isotopes. Experimental conditions improved substantially after commissioning of the HIE-ISOLDE project at CERN with higher secondary-beam intensity, higher beam energy and better beam quality. We review the spectroscopy achievements obtained at REX-ISOLDE and first published results from HIE-ISOLDE. (C) 2020 Elsevier B.V. All rights reserved.
Published: 2020

29. Decay studies of the long-lived states in Tl-186

Author: Stryjczyk, M., Andel, B., Andreyev, A. N., Cubiss, J., Pakarinen, J., Rezynkina, K., Van Duppen, P., Antalic, S., Berry, T., Borge, M. J. G., Clisu, C., Cox, D. M., De Witte, H., Fraile, L. M., Fynbo, H. O. U., Gaffney, L. P., Harkness-Brennan, L. J., Huyse, M., Illana, A., Judson, D. S., Konki, J., Kurcewicz, J., Lazarus, I, Lica, R., Madurga, M., Marginean, N., Marginean, R., Mihai, C., Mosat, P., Nacher, E., Negret, A., Ojala, J., Ovejas, J. D., Page, R. D., Papadakis, P., Pascu, S., Perea, A., Podolyak, Zs, Pucknell, V, Rapisarda, E., Rotaru, F., Sotty, C., Tengblad, O., Vedia, V., Vinals, S., Wadsworth, R., Warr, N., Wrzosek-Lipska, K., Stryjczyk, M., Andel, B., Andreyev, A. N., Cubiss, J., Pakarinen, J., Rezynkina, K., Van Duppen, P., Antalic, S., Berry, T., Borge, M. J. G., Clisu, C., Cox, D. M., De Witte, H., Fraile, L. M., Fynbo, H. O. U., Gaffney, L. P., Harkness-Brennan, L. J., Huyse, M., Illana, A., Judson, D. S., Konki, J., Kurcewicz, J., Lazarus, I, Lica, R., Madurga, M., Marginean, N., Marginean, R., Mihai, C., Mosat, P., Nacher, E., Negret, A., Ojala, J., Ovejas, J. D., Page, R. D., Papadakis, P., Pascu, S., Perea, A., Podolyak, Zs, Pucknell, V, Rapisarda, E., Rotaru, F., Sotty, C., Tengblad, O., Vedia, V., Vinals, S., Wadsworth, R., Warr, N., and Wrzosek-Lipska, K.
Abstract: Decay spectroscopy of the long-lived states in Tl-186 has been performed at the ISOLDE Decay Station at ISOLDE, CERN. The a decay from the low-spin (2(-)) state in Tl-186 was observed for the first time and a half-life of 3.4(-0.)(4)(+0.5) s was determined. Based on the alpha-decay energy, the relative positions of the long-lived states were fixed, with the (2(-)) state as the ground state, the 7((+)) state at 77(56) keV, and the 10((-)) state at 451(56) keV. The level scheme of the internal decay of the Tl-186(10((-))) state [T-1/2 = 3.40(9) s], which was known to decay solely through emission of 374-keV gamma-ray transition, was extended and a lower limit for the beta-decay branching b(beta) > 5.9(3)% was determined. The extracted retardation factors for the gamma decay of the 10((-) )state were compared to the available data in neighboring odd-odd thallium isotopes indicating the importance of the pi d(3/2) shell in the isomeric decay and significant structure differences between Tl-184 and Tl-186.
Published: 2020

30. Lifetime measurements of Er-162: Evolution of collectivity in the rare-earth region

Author: Knafla, L., Hafner, G., Jolie, J., Regis, J-M, Karayonchev, V, Blazhev, A., Esmaylzadeh, A., Fransen, C., Goldkuhle, A., Herb, S., Muller-Gatermann, C., Warr, N., Zell, K. O., Knafla, L., Hafner, G., Jolie, J., Regis, J-M, Karayonchev, V, Blazhev, A., Esmaylzadeh, A., Fransen, C., Goldkuhle, A., Herb, S., Muller-Gatermann, C., Warr, N., and Zell, K. O.
Abstract: Lifetimes of low-lying yrast states in Er-162 are measured using the electronic gamma-gamma fast-timing technique. Excited states were populated in a Sm-154(C-12, (4)n)Er-162 fusion-evaporation reaction and gamma rays were detected in a combined setup of high purity germanium and LaBr3(Ce) scintillation detectors. The lifetimes of the 4(1)(+) and 6(1)(+) states are determined for the first time and the lifetimes of the 2(1)(+) and 7- states are remeasured with higher precision. Reduced transition probabilities are extracted and well reproduced by theoretical calculations in the framework of the confined beta soft model and the interacting boson model.
Published: 2020

31. Restoring the valence-shell stabilization in Nd-140

Author: Kern, R., Zidarova, R., Pietralla, N., Rainovski, G., Stegmann, R., Blazhev, A., Boukhari, A., Cederkall, J., Cubiss, J. G., Djongolov, M., Fransen, C., Gaffney, L. P., Gladnishki, K., Giannopoulos, E., Hess, H., Jolie, J., Karayonchev, V, Kaya, L., Keatings, J. M., Kocheva, D., Kroell, Th, Moeller, O., O'Neill, G. G., Pakarinen, J., Reiter, P., Rosiak, D., Scheck, M., Snall, J., Soederstroem, P-A, Spagnoletti, P., Stoyanova, M., Thiel, S., Vogt, A., Warr, N., Welker, A., Werner, V, Wiederhold, J., De Witte, H., Kern, R., Zidarova, R., Pietralla, N., Rainovski, G., Stegmann, R., Blazhev, A., Boukhari, A., Cederkall, J., Cubiss, J. G., Djongolov, M., Fransen, C., Gaffney, L. P., Gladnishki, K., Giannopoulos, E., Hess, H., Jolie, J., Karayonchev, V, Kaya, L., Keatings, J. M., Kocheva, D., Kroell, Th, Moeller, O., O'Neill, G. G., Pakarinen, J., Reiter, P., Rosiak, D., Scheck, M., Snall, J., Soederstroem, P-A, Spagnoletti, P., Stoyanova, M., Thiel, S., Vogt, A., Warr, N., Welker, A., Werner, V, Wiederhold, J., and De Witte, H.
Abstract: A projectile Coulomb-excitation experiment was performed at the radioactive-ion beam facility HIE-ISOLDE at CERN to obtain E2 and M1 transition matrix elements of Nd-140 using the multistep Coulomb-excitation code GOSIA. The absolute M1 strengths, B(M1; 2(2)(-) -> 2(1)(+)) = 0.033(8)mu(2)(N), B(M1 ; 2(3)(+) -> 2(1)(+)) = 0.26(-0.10)(+0.11)mu(2)(N), and B(M1; 2(4)+ -> 2(1)(+)) < 0.04 mu(2)(N) identify the 2(3)(+) state as the main fragment of the one-quadrupole-phonon proton-neutron mixed-symmetry state of Nd-140. The degree of F-spin mixing in Nd-140 was quantified with the determination of the mixing matrix element VF-mix < 7(-7)(-13) keV.
Published: 2020

32. Competition between Allowed and First-Forbidden beta Decay: The Case of Hg-208 -> Tl-2(0)8

Author: Carroll, R. J., Podolyak, Zs, Berry, T., Grawe, H., Alexander, T., Andreyev, A. N., Ansari, S., Borge, M. J. G., Brunet, M., Creswell, J. R., Fraile, L. M., Fahlander, C., Fynbo, H. O. U., Gamba, E. R., Gelletly, W., Gerst, R-B, Gorska, M., Gredley, A., Greenlees, P. T., Harkness-Brennan, L. J., Huyse, M., Judge, S. M., Judson, D. S., Konki, J., Kurcewicz, J., Kuti, I, Lalkovski, S., Lazarus, I. H., Lica, R., Lund, M., Madurga, M., Marginean, N., Marginean, R., Marroquin, I, Mihai, C., Mihai, R. E., Nacher, E., Negret, A., Nita, C., Pascu, S., Page, R. D., Patel, Z., Perea, A., Phrompao, J., Piersa, M., Pucknell, V, Rahkila, P., Rapisarda, E., Regan, P. H., Rotaru, F., Rudigier, M., Shand, C. M., Shearman, R., Stegemann, S., Stora, T., Sotty, Ch, Tengblad, O., Van Duppen, P., Vedia, V., Wadsworth, R., Walker, P. M., Warr, N., Wearing, F., De Witte, H., Carroll, R. J., Podolyak, Zs, Berry, T., Grawe, H., Alexander, T., Andreyev, A. N., Ansari, S., Borge, M. J. G., Brunet, M., Creswell, J. R., Fraile, L. M., Fahlander, C., Fynbo, H. O. U., Gamba, E. R., Gelletly, W., Gerst, R-B, Gorska, M., Gredley, A., Greenlees, P. T., Harkness-Brennan, L. J., Huyse, M., Judge, S. M., Judson, D. S., Konki, J., Kurcewicz, J., Kuti, I, Lalkovski, S., Lazarus, I. H., Lica, R., Lund, M., Madurga, M., Marginean, N., Marginean, R., Marroquin, I, Mihai, C., Mihai, R. E., Nacher, E., Negret, A., Nita, C., Pascu, S., Page, R. D., Patel, Z., Perea, A., Phrompao, J., Piersa, M., Pucknell, V, Rahkila, P., Rapisarda, E., Regan, P. H., Rotaru, F., Rudigier, M., Shand, C. M., Shearman, R., Stegemann, S., Stora, T., Sotty, Ch, Tengblad, O., Van Duppen, P., Vedia, V., Wadsworth, R., Walker, P. M., Warr, N., Wearing, F., and De Witte, H.
Abstract: The beta decay of Hg-208 into the one-proton hole, one neutron-particle Tl-208(81)127 nucleus was investigated at CERN-ISOLDE. Shell-model calculations describe well the level scheme deduced, validating the proton-neutron interactions used, with implications for the whole of the N > 126, Z < 82 quadrant of neutron-rich nuclei. While both negative and positive parity states with spin 0 and 1 are expected within the Q(beta) window, only three negative parity states are populated directly in the beta decay. The data provide a unique test of the competition between allowed Gamow-Teller and Fermi, and first-forbidden beta decays, essential for the understanding of the nucleosynthesis of heavy nuclei in the rapid neutron capture process. Furthermore, the observation of the parity changing 0(+) -> 0(-)beta decay where the daughter state is core excited is unique, and can provide information on mesonic corrections of effective operators.
Published: 2020

33. Population of lead isotopes in binary reactions using a Rb-94 radioactive beam

Author: Colovic, P., Szilner, S., Illana, A., Valiente-Dobon, J. J., Corradi, L., Pollarolo, G., Mijatovic, T., Goasduff, A., Benzoni, G., Borge, M. J. G., Boso, A., Boukhari, A., Ceruti, S., Cubiss, J. G., de Angelis, G., De Witte, H., Fioretto, E., Fransen, Ch, Galtarossa, F., Gaffney, L. P., Giannopoulos, E., Hess, H., Jurado-Gomez, M. L., Kaya, L., Kroell, Th, Marchi, T., Menegazzo, R., Mengoni, D., Napoli, D. R., O'Neill, G., Pakarinen, J., Podolyak, Zs, Recchia, F., Reiter, P., Rosiak, D., Snall, J., Spagnoletti, P., Testov, D., Thiel, S., Warr, N., Zidarova, R., Colovic, P., Szilner, S., Illana, A., Valiente-Dobon, J. J., Corradi, L., Pollarolo, G., Mijatovic, T., Goasduff, A., Benzoni, G., Borge, M. J. G., Boso, A., Boukhari, A., Ceruti, S., Cubiss, J. G., de Angelis, G., De Witte, H., Fioretto, E., Fransen, Ch, Galtarossa, F., Gaffney, L. P., Giannopoulos, E., Hess, H., Jurado-Gomez, M. L., Kaya, L., Kroell, Th, Marchi, T., Menegazzo, R., Mengoni, D., Napoli, D. R., O'Neill, G., Pakarinen, J., Podolyak, Zs, Recchia, F., Reiter, P., Rosiak, D., Snall, J., Spagnoletti, P., Testov, D., Thiel, S., Warr, N., and Zidarova, R.
Abstract: We measured absolute cross sections for neutron transfer channels populated in the Rb-94 + Pb-208 binary reaction. Cross sections have been extracted identifying directly the lead isotopes with the high efficiency MINIBALL gamma-ray array coupled to a particle detector combined with a radioactive Rb-94 beam delivered at E-lab = 6.2 MeV/nucleon by the HIE-ISOLDE facility. We observed sizable cross sections in the neutron-rich mass region, where the heavy partner acquires neutrons. A fair agreement between the measured cross sections with those from GRAZING calculations gives confidence in the cross-section predictions of more neutron-rich nuclei produced via a larger number of transferred nucleons.
Published: 2020

34. Lifetime measurements of excited states in neutron-rich Ti-53: Benchmarking effective shell-model interactions

Author: Goldkuhle, A., Blazhev, A., Fransen, C., Dewald, A., Beckers, M., Birkenbach, B., Braunroth, T., Clement, E., Dudouet, J., Eberth, J., Hess, H., Jacquot, B., Jolie, J., Kim, Y-H, Lemasson, A., Lenzi, S. M., Li, H. J., Litzinger, J., Michelagnoli, C., Mueller-Gatermann, C., Singh, B. S. Nara, Perez-Vidal, R. M., Ralet, D., Reiter, P., Vogt, A., Warr, N., Zell, K. O., Goldkuhle, A., Blazhev, A., Fransen, C., Dewald, A., Beckers, M., Birkenbach, B., Braunroth, T., Clement, E., Dudouet, J., Eberth, J., Hess, H., Jacquot, B., Jolie, J., Kim, Y-H, Lemasson, A., Lenzi, S. M., Li, H. J., Litzinger, J., Michelagnoli, C., Mueller-Gatermann, C., Singh, B. S. Nara, Perez-Vidal, R. M., Ralet, D., Reiter, P., Vogt, A., Warr, N., and Zell, K. O.
Abstract: Level lifetimes of the yrast (5/2(-)) to 13/2(-) states in the neutron-rich nucleus Ti-53, produced in a multinucleon-transfer reaction, have been measured for the first time. The recoil distance Doppler-shift method was employed and lifetimes of the excited states were extracted by a lineshape analysis aided by GEANT4-based Monte-Carlo simulations. The experiment was performed at the Grand Accelerateur National d'Ions Lourds facility in Caen, France, by using the Advanced Gamma Tracking Array for the gamma-ray detection coupled to the large-acceptance variable mode spectrometer for an event-by-event particle identification and the Cologne plunger for deep-inelastic reactions. Reduced transition probabilities, deduced from the lifetimes, give new information on the nuclear structure of Ti-53, and are used to benchmark different shell-model calculations using established interactions in the f p shell.
Published: 2020

35. Tests of collectivity in Zr-98 by absolute transition rates

Author: Karayonchev, V, Jolie, J., Blazhev, A., Dewald, A., Esmaylzadeh, A., Fransen, C., Haefner, G., Knafla, L., Litzinger, J., Muller-Gatermann, C., Regis, J-M, Schomacker, K., Vogt, A., Warr, N., Leviatan, A., Gavrielov, N., Karayonchev, V, Jolie, J., Blazhev, A., Dewald, A., Esmaylzadeh, A., Fransen, C., Haefner, G., Knafla, L., Litzinger, J., Muller-Gatermann, C., Regis, J-M, Schomacker, K., Vogt, A., Warr, N., Leviatan, A., and Gavrielov, N.
Abstract: Lifetimes of low-spin excited states in Zr-98 were measured using the recoil-distance Doppler-shift technique , and the Doppler-shift attenuation method. The nucleus of interest was populated in a( 96)zr(O-18, O-16) Zr-98 two- neutron transfer reaction at the Cologne FN Tandem accelerator. Lifetimes of six low-spin excited states, of which four are unknown, were measured. The deduced B(E2) values were compared with Monte Carlo shell model and interacting boson model with configuration mixing calculations. Both approaches reproduce well most of the data but leave challenging questions regarding the structure of some low-lying states.
Published: 2020

36. Lifetime measurements in the odd-A nucleus Hf-177

Author: Knafla, L., Alexa, P., Koester, U., Thiamova, G., Regis, J-M, Jolie, J., Blanc, A., Bruce, A. M., Esmaylzadeh, A., Fraile, L. M., de France, G., Haefner, G., Ilieva, S., Jentschel, M., Karayonchev, V, Korten, W., Kroell, T., Lalkovski, S., Leoni, S., Mach, H., Marginean, N., Mutti, P., Pascovici, G., Paziy, V, Podolyak, Zs, Regan, P. H., Roberts, O. J., Saed-Samii, N., Simpson, G. S., Smith, J. F., Soldner, T., Townsley, C., Ur, C. A., Urban, W., Vancraeyenest, A., Warr, N., Knafla, L., Alexa, P., Koester, U., Thiamova, G., Regis, J-M, Jolie, J., Blanc, A., Bruce, A. M., Esmaylzadeh, A., Fraile, L. M., de France, G., Haefner, G., Ilieva, S., Jentschel, M., Karayonchev, V, Korten, W., Kroell, T., Lalkovski, S., Leoni, S., Mach, H., Marginean, N., Mutti, P., Pascovici, G., Paziy, V, Podolyak, Zs, Regan, P. H., Roberts, O. J., Saed-Samii, N., Simpson, G. S., Smith, J. F., Soldner, T., Townsley, C., Ur, C. A., Urban, W., Vancraeyenest, A., and Warr, N.
Abstract: Lifetimes of low- and high-spin states in the odd-A nucleus Hf-177 were measured during the EXILL&FATIMA campaign using a spectrometer equipped with eight HPGe-Clover detectors and 16 fast-timing LaBr3(Ce) detectors. For the determination of lifetimes in the pico- to nanosecond regime, the well-established generalized centroid difference method was used. Lifetimes of the 9/2(-), 9/2(+), 11/2(-), 11/2(+) states were remeasured, the lifetimes of the 13/2(-), 17/2(-), 13/2(+), 15/2(+), and 17/2(+) states were determined for the first time and an upper limit for the 19/2(+) state has been established. From these lifetimes absolute reduced transition probabilities were extracted and compared to particle-rotor-model calculations and quasiparticle-phonon-model calculations showing the importance of including multipole-multipole interactions in the description of odd-A nuclei in the rare earth region.
Published: 2020

37. Prompt and delayed gamma spectroscopy of neutron-rich Kr-94 and observation of a new isomer

Author: Gerst, R-B, Blazhev, A., Warr, N., Wilson, J. N., Lebois, M., Jovancevic, N., Thisse, D., Canavan, R., Rudigier, M., Etasse, D., Adamska, E., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Courtin, S., Cortes, M. L., Davies, P., Delafosse, C., Fallot, M., Fornal, B., Fraile, L. M., Gjestvang, D., Gottardo, A., Guadilla, V, Haefner, G., Hauschild, K., Heine, M., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Ivanov, P., Jazrawi, S., Korgul, A., Koseoglou, P., Kroell, T., Kurtukian-Nieto, T., Le Meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Lozeva, R., Matea, I, Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Reygadas-Tello, D., Rezynkina, K., Sanchez-Tembleque, V, Schmitt, C., Soederstroem, P-A, Suerder, C., Tocabens, G., Vedia, V., Verney, D., Wasilewska, B., Wiederhold, J., Yavachova, M., Zeiser, F., Ziliani, S., Gerst, R-B, Blazhev, A., Warr, N., Wilson, J. N., Lebois, M., Jovancevic, N., Thisse, D., Canavan, R., Rudigier, M., Etasse, D., Adamska, E., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Benzoni, G., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Courtin, S., Cortes, M. L., Davies, P., Delafosse, C., Fallot, M., Fornal, B., Fraile, L. M., Gjestvang, D., Gottardo, A., Guadilla, V, Haefner, G., Hauschild, K., Heine, M., Henrich, C., Homm, I, Ibrahim, F., Iskra, L. W., Ivanov, P., Jazrawi, S., Korgul, A., Koseoglou, P., Kroell, T., Kurtukian-Nieto, T., Le Meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Lozeva, R., Matea, I, Miernik, K., Nemer, J., Oberstedt, S., Paulsen, W., Piersa, M., Popovitch, Y., Porzio, C., Qi, L., Ralet, D., Regan, P. H., Reygadas-Tello, D., Rezynkina, K., Sanchez-Tembleque, V, Schmitt, C., Soederstroem, P-A, Suerder, C., Tocabens, G., Vedia, V., Verney, D., Wasilewska, B., Wiederhold, J., Yavachova, M., Zeiser, F., and Ziliani, S.
Abstract: Prompt and delayed gamma-ray spectroscopy of the neutron-rich Kr-94 was performed, as part of the fission campaign at the ALTO facility of the IPN Orsay, using the fast-neutron-induced fission reaction U-238(n, f) in combination with the nu-Ball array, a novel hybrid gamma spectrometer for energy and lifetime measurements. Several new yrast and nonyrast transitions were observed for the first time, extending the previously known level scheme. Additionally, we report on the observation of a new short-lived isomer at 3444 keV with a half-life of 32(3) ns. The analysis of the Nilsson orbitals obtained from Gogny cranked Hartree-Fock-Bogoliubov calculations suggests a (9(-)) spin and an oblate deformation for this isomer corresponding to a two-quasineutron state, indicating an isomeric structure very similar to that of the neighboring isotones Sr-96 and Se-92.
Published: 2020

38. The observation of vibrating pear shapes in radon nuclei: update

Author: Butler, P. A., Gaffney, L. P., Spagnoletti, P., Konki, J., Scheck, M., Smith, J. F., Abrahams, K., Bowry, M., Cederkäll, J., Chupp, T., De Angelis, G., De Witte, H., Garrett, P. E., Goldkuhle, A., Henrich, C., Illana, A., Johnston, K., Joss, D. T., Keatings, J. M., Kelly, N. A., Komorowska, M., Kröll, T., Lozano, M., Singh, B. S. Nara, O'Donnell, D., Ojala, J., Page, R. D., Pedersen, L. G., Raison, C., Reiter, P., Rodriguez, J. A., Rosiak, D., Rothe, S., Seidlitz, M., Shneidman, T. M., Siebeck, B., Sinclair, J., Stryjczyk, M., Van Duppen, P., Vinals, S., Virtanen, V., Warr, N., Wrzosek-Lipska, K., Zielińska, M., Butler, P. A., Gaffney, L. P., Spagnoletti, P., Konki, J., Scheck, M., Smith, J. F., Abrahams, K., Bowry, M., Cederkäll, J., Chupp, T., De Angelis, G., De Witte, H., Garrett, P. E., Goldkuhle, A., Henrich, C., Illana, A., Johnston, K., Joss, D. T., Keatings, J. M., Kelly, N. A., Komorowska, M., Kröll, T., Lozano, M., Singh, B. S. Nara, O'Donnell, D., Ojala, J., Page, R. D., Pedersen, L. G., Raison, C., Reiter, P., Rodriguez, J. A., Rosiak, D., Rothe, S., Seidlitz, M., Shneidman, T. M., Siebeck, B., Sinclair, J., Stryjczyk, M., Van Duppen, P., Vinals, S., Virtanen, V., Warr, N., Wrzosek-Lipska, K., and Zielińska, M.
Abstract: There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the standard model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we have observed the low-lying quantum states in $^{224}$Rn and $^{226}$Rn by accelerating beams of these radioactive nuclei. We report here additional states not assigned in our 2019 publication. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment., Comment: Updated from Nat. Comm. 10 (2019) 2473
Published: 2020
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39. Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive $^{222}$Ra and $^{228}$Ra Beams

Author: Butler, P. A., Gaffney, L. P., Spagnoletti, P., Abrahams, K., Bowry, M., Cederkäll, J., De Angelis, G., De Witte, H., Garrett, P. E., Goldkuhle, A., Henrich, C., Illana, A., Johnston, K., Joss, D. T., Keatings, J. M., Kelly, N. A., Komorowska, M., Konki, J., Kröll, T., Lozano, M., Singh, B. S. Nara, O'Donnell, D., Ojala, J., Page, R. D., Pedersen, L. G., Raison, C., Reiter, P., Rodriguez, J. A., Rosiak, D., Rothe, S., Scheck, M., Seidlitz, M., Shneidman, T. M., Siebeck, B., Sinclair, J., Smith, J. F., Stryjczyk, M., Van Duppen, P., Vinals, S., Virtanen, V., Warr, N., Wrzosek-Lipska, K., Zielińska, M., Butler, P. A., Gaffney, L. P., Spagnoletti, P., Abrahams, K., Bowry, M., Cederkäll, J., De Angelis, G., De Witte, H., Garrett, P. E., Goldkuhle, A., Henrich, C., Illana, A., Johnston, K., Joss, D. T., Keatings, J. M., Kelly, N. A., Komorowska, M., Konki, J., Kröll, T., Lozano, M., Singh, B. S. Nara, O'Donnell, D., Ojala, J., Page, R. D., Pedersen, L. G., Raison, C., Reiter, P., Rodriguez, J. A., Rosiak, D., Rothe, S., Scheck, M., Seidlitz, M., Shneidman, T. M., Siebeck, B., Sinclair, J., Smith, J. F., Stryjczyk, M., Van Duppen, P., Vinals, S., Virtanen, V., Warr, N., Wrzosek-Lipska, K., and Zielińska, M.
Abstract: There is sparse direct experimental evidence that atomic nuclei can exhibit stable pear shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole ($E3$) matrix elements have been determined for transitions in $^{222,228}$Ra nuclei using the method of sub-barrier, multi-step Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of $E$3 matrix elements for different nuclear transitions is explained by describing $^{222}$Ra as pear-shaped with stable octupole deformation, while $^{228}$Ra behaves like an octupole vibrator., Comment: to be published in Physical Review Letters
Published: 2020
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40. gamma-RAY SPECTROSCOPY OF Se-85 PRODUCED IN Th-232 FISSION

Author: Adamska, E., Korgul, A., Fijalkowska, A., Miernik, K., Piersa, M., Canavan, R., Etasse, D., Jovancevic, N., Lebois, M., Rudigier, M., Thisse, D., Wilson, J. N., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Blazhev, A., Benzoni, G., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Ciemala, M., Collins, S., Cortes, L., Davies, P., Delafosse, C., Fallot, M., Fornal, B., Fraile, L. M., Gerst, R. -B., Gjestvang, D., Gottardo, A., Guadilla, V., Hafner, G., Hauschild, K., Heine, M., Henrich, C., Homm, I., Ibrahim, F., Iskra, L. W., Koseoglou, P., Kroell, T., Kurtukian-Nieto, T., Le-Meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Lozeva, R., Matea, I., Nemer, J., Oberstedt, S., Paulsen, W., Popovitch, Y., Qi, L., Ralet, D., Regan, P. H., Tello, D. Reygadas, Rezynkina, K., Sanchez-Tembleque, V., Schmitt, C., Soederstroem, P. -A., Surder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M., Zeiser, F., Adamska, E., Korgul, A., Fijalkowska, A., Miernik, K., Piersa, M., Canavan, R., Etasse, D., Jovancevic, N., Lebois, M., Rudigier, M., Thisse, D., Wilson, J. N., Adsley, P., Algora, A., Babo, M., Belvedere, K., Benito, J., Blazhev, A., Benzoni, G., Boso, A., Bottoni, S., Bunce, M., Chakma, R., Cieplicka-Orynczak, N., Ciemala, M., Collins, S., Cortes, L., Davies, P., Delafosse, C., Fallot, M., Fornal, B., Fraile, L. M., Gerst, R. -B., Gjestvang, D., Gottardo, A., Guadilla, V., Hafner, G., Hauschild, K., Heine, M., Henrich, C., Homm, I., Ibrahim, F., Iskra, L. W., Koseoglou, P., Kroell, T., Kurtukian-Nieto, T., Le-Meur, L., Leoni, S., Ljungvall, J., Lopez-Martens, A., Lozeva, R., Matea, I., Nemer, J., Oberstedt, S., Paulsen, W., Popovitch, Y., Qi, L., Ralet, D., Regan, P. H., Tello, D. Reygadas, Rezynkina, K., Sanchez-Tembleque, V., Schmitt, C., Soederstroem, P. -A., Surder, C., Tocabens, G., Vedia, V., Verney, D., Warr, N., Wasilewska, B., Wiederhold, J., Yavahchova, M., and Zeiser, F.
Abstract: Excited states in the neutron-rich Se-85 nucleus have been studied using for the first time a fast neutron-induced fission of Th-232. The experiment was performed at the ALTO facility of the IPN Orsay. Coupling of the LICORNE directional neutron source with the nu-ball high-resolution gamma-ray spectrometer provided unique access to high-spin states in neutron-rich fission fragments from the Th-232(n,f) reaction. A preliminary level scheme of Se-85 was established by the analysis of prompt gamma-gamma-gamma coincidences. Identification of the all known yrast states in Se-85 is the first step towards studies of more neutron-rich Se isotopes.
Published: 2020

41. Search for proton emission of the isomeric 10(+) state in Ni-54

Author: Stahl, K., Wendt, A., Reiter, P., Rudolph, D., Blazhev, A., Bruyneel, B., Eberth, J., Fahlander, C., Fransen, C., Golubev, P., Hess, H., Hoischen, R., Holler, A., Kalkuehler, M., Kotthaus, T., Lersch, D., Pascovici, G., Seidlitz, M., Siebeck, B., Taprogge, J., Warr, N., Wiens, A., Zell, O., Stahl, K., Wendt, A., Reiter, P., Rudolph, D., Blazhev, A., Bruyneel, B., Eberth, J., Fahlander, C., Fransen, C., Golubev, P., Hess, H., Hoischen, R., Holler, A., Kalkuehler, M., Kotthaus, T., Lersch, D., Pascovici, G., Seidlitz, M., Siebeck, B., Taprogge, J., Warr, N., Wiens, A., and Zell, O.
Abstract: Several experiments were conducted at the 10 MV Van-de-Graaff tandem accelerator at the Institute of Nuclear Physics, Cologne, to detect proton emission from the isomeric 6457-keV 10(+) state in Ni-54. Excitation functions for two fusion-evaporation reactions were measured to maximise the population of the rare two-neutron evaporation channel from a Ni-56 compound nucleus. The search for delayed proton emission was based on the Si-28(Si-28, 2n)Ni-54 reaction at a beam energy of 70 MeV. For this reaction, a cross-section limit for the population of the 10(+) state in Ni-54 and its proton-decay branch was determined to be sigma < 22 nb.
Published: 2020

42. Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive Ra-222 and Ra-228 Beams

Author: Butler, P. A., Gaffney, L. P., Spagnoletti, P., Abrahams, K., Bowry, M., Cederkall, J., de Angelis, G., De Witte, H., Garrett, P. E., Goldkuhle, A., Henrich, C., Illana, A., Johnston, K., Joss, D. T., Keatings, J. M., Kelly, N. A., Komorowska, M., Konki, J., Kroell, T., Lozano, M., Singh, B. S. Nara, O'Donnell, D., Ojala, J., Page, R. D., Pedersen, L. G., Raison, C., Reiter, P., Rodriguez, J. A., Rosiak, D., Rothe, S., Scheck, M., Seidlitz, M., Shneidman, T. M., Siebeck, B., Sinclair, J., Smith, J. F., Stryjczyk, M., Van Duppen, P., Vinals, S., Virtanen, V., Warr, N., Wrzosek-Lipska, K., Zielinska, M., Butler, P. A., Gaffney, L. P., Spagnoletti, P., Abrahams, K., Bowry, M., Cederkall, J., de Angelis, G., De Witte, H., Garrett, P. E., Goldkuhle, A., Henrich, C., Illana, A., Johnston, K., Joss, D. T., Keatings, J. M., Kelly, N. A., Komorowska, M., Konki, J., Kroell, T., Lozano, M., Singh, B. S. Nara, O'Donnell, D., Ojala, J., Page, R. D., Pedersen, L. G., Raison, C., Reiter, P., Rodriguez, J. A., Rosiak, D., Rothe, S., Scheck, M., Seidlitz, M., Shneidman, T. M., Siebeck, B., Sinclair, J., Smith, J. F., Stryjczyk, M., Van Duppen, P., Vinals, S., Virtanen, V., Warr, N., Wrzosek-Lipska, K., and Zielinska, M.
Abstract: There is sparse direct experimental evidence that atomic nuclei can exhibit stable pear shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole (E3) matrix elements have been determined for transitions in Ra-222,Ra-228 nuclei using the method of sub-barrier, multistep Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of E3 matrix elements for different nuclear transitions is explained by describing Ra-222 as pear shaped with stable octupole deformation, while Ra-228 behaves like an octupole vibrator.
Published: 2020

43. Shape coexistence and multiparticle-multihole structures in Cd-110,Cd-112

Author: Garrett, P. E., Rodriguez, T. R., Varela, A. Diaz, Green, K. L., Bangay, J., Finlay, A., Austin, R. A. E., Ball, G. C., Bandyopadhyay, D. S., Bildstein, V, Colosimo, S., Cross, D. S., Demand, G. A., Finlay, P., Garnsworthy, A. B., Grinyer, G. F., Hackman, G., Jigmeddorj, B., Jolie, J., Kulp, W. D., Leach, K. G., Morton, A. C., Orce, J. N., Pearson, C. J., Phillips, A. A., Radich, A. J., Rand, E. T., Schumaker, M. A., Svensson, C. E., Sumithrarachchi, C., Triambak, S., Warr, N., Wong, J., Wood, J. L., Yates, S. W., Garrett, P. E., Rodriguez, T. R., Varela, A. Diaz, Green, K. L., Bangay, J., Finlay, A., Austin, R. A. E., Ball, G. C., Bandyopadhyay, D. S., Bildstein, V, Colosimo, S., Cross, D. S., Demand, G. A., Finlay, P., Garnsworthy, A. B., Grinyer, G. F., Hackman, G., Jigmeddorj, B., Jolie, J., Kulp, W. D., Leach, K. G., Morton, A. C., Orce, J. N., Pearson, C. J., Phillips, A. A., Radich, A. J., Rand, E. T., Schumaker, M. A., Svensson, C. E., Sumithrarachchi, C., Triambak, S., Warr, N., Wong, J., Wood, J. L., and Yates, S. W.
Abstract: From detailed spectroscopy of Cd-110 and Cd-112 following the beta(+)/EC decay of In-110,In-112 and the beta(-) decay of Ag-112, the presence of very weak decay branches from nonyrast states is revealed. In Cd-112, 2(5)(+) -> 0(4)(+) and 4(6)(+) -> 2(5)(+) transitions are observed that yield B(E2; 2(5)(+) -> 0(4)(+)) = 34 +/- 15 W.u. and B(E2; 4(6)(+) -> 2(5)(+)) = 77 +/- 30 W.u., respectively, clearly indicating a collective structure. In 110Cd, a weak decay branch from the 4(6)(+) level to the 2(5)(+) level is observed, and from a lifetime measurement following the (n, n gamma' reaction, B(E2; 4(6)(+) -> 2(5)(+)) = 55 +/- 14 W.u. is determined. A new branch is also observed for the decay of the 6(4)(+) level to the 4(6)(+) state, indicating that the sequence 2(5)(+), 4(6)(+), and 6(4)(+) forms part of a collective structure. The presence of 3(3)(+) and 5(2)(+) levels spaced between the previous sequence is highly suggestive of a gamma band built on the 0(2)(+) shape-coexisting intruder state. The 0(4)(+) levels in Cd-110,Cd-112,Cd-114 have preferred decays to the lowest 2(+) members of the intruder bands, and for 114Cd a previous measurement had established an enhanced B(E2; 0(4)(+) -> 2(3)(+)). The energy systematics of the 0(2)(+), 0(3)(+), and 0(4)(+) levels all display the characteristic parabolic-shaped pattern, suggesting that they are built on multiparticle-multihole proton excitations. The results are compared with beyond-mean-field calculations that reproduce qualitatively the observed levels and their decays and suggest that the 0(1)(+), 0(2)(+), 0(3)(+), and 0(4)(+) levels and the excited states built on them possess different deformations.
Published: 2020

44. Octupole states in Tl-207 studied through beta decay

Author: Berry, T. A., Podolyak, Zs, Carroll, R. J., Lica, R., Brown, B. A., Grawe, H., Sotty, Ch, Timofeyuk, N. K., Alexander, T., Andreyev, A. N., Ansari, S., Borge, M. J. G., Brunet, M., Cresswell, J. R., Fahlander, C., Fraile, L. M., Fynbo, H. O. U., Gamba, E., Gelletly, W., Gerst, R-B, Gorska, M., Gredley, A., Greenlees, P., Harkness-Brennan, L. J., Huyse, M., Judge, S. M., Judson, D. S., Konki, J., Kowalska, M., Kurcewicz, J., Kuti, I, Lalkovski, S., Lazarus, I, Lund, M., Madurga, M., Marginean, N., Mihai, C., Mihai, R. E., Nacher, E., Negret, A., Nae, S., Nita, C., Pascu, S., Page, R. D., Patel, Z., Perea, A., Phrompao, J., Piersa, M., Pucknell, V, Rahkila, P., Rapisarda, E., Regan, P. H., Rotaru, F., Rudigier, M., Shand, C. M., Shearman, R., Simpson, E. C., Stegemann, S., Stora, T., Tengblad, O., Turturica, A., Van Duppen, P., Vedia, V., Walker, P. M., Warr, N., Wearing, F. P., De Witte, H., Berry, T. A., Podolyak, Zs, Carroll, R. J., Lica, R., Brown, B. A., Grawe, H., Sotty, Ch, Timofeyuk, N. K., Alexander, T., Andreyev, A. N., Ansari, S., Borge, M. J. G., Brunet, M., Cresswell, J. R., Fahlander, C., Fraile, L. M., Fynbo, H. O. U., Gamba, E., Gelletly, W., Gerst, R-B, Gorska, M., Gredley, A., Greenlees, P., Harkness-Brennan, L. J., Huyse, M., Judge, S. M., Judson, D. S., Konki, J., Kowalska, M., Kurcewicz, J., Kuti, I, Lalkovski, S., Lazarus, I, Lund, M., Madurga, M., Marginean, N., Mihai, C., Mihai, R. E., Nacher, E., Negret, A., Nae, S., Nita, C., Pascu, S., Page, R. D., Patel, Z., Perea, A., Phrompao, J., Piersa, M., Pucknell, V, Rahkila, P., Rapisarda, E., Regan, P. H., Rotaru, F., Rudigier, M., Shand, C. M., Shearman, R., Simpson, E. C., Stegemann, S., Stora, T., Tengblad, O., Turturica, A., Van Duppen, P., Vedia, V., Walker, P. M., Warr, N., Wearing, F. P., and De Witte, H.
Abstract: The beta decay of Hg-207 into the single-proton-hole nucleus Tl-207 has been studied through gamma-ray spectroscopy at the ISOLDE Decay Station (IDS) with the aim of identifying states resulting from coupling of the pi s(1/2)(-1), pi d(3/2)(-1) and pi h(11/2)(-1) shell model orbitals to the collective octupole vibration. Twenty-two states were observed lying between 2.6 and 4.0 MeV, eleven of which were observed for the first time, and 78 new transitions were placed. Two octupole states (s(3/2)-coupled) are identified and three more states (d(3/2)-coupled) are tentatively assigned using spin-parity inferences, while further h(11/2)-coupled states may also have been observed for the first time. Comparisons are made with state-of-the-art large-scale shell model calculations and previous observations made in this region, and systematic underestimation of the energy of the octupole vibrational states is noted. We suggest that in order to resolve the difference in predicted energies for collective and noncollective t = 1 states (t is the number of nucleons breaking the Pb-208 core), the effect of t = 2 mixing may be reduced for octupole-coupled states. The inclusion of mixing with t = 0, 2, 3 excitations is necessary to replicate all t = 1 state energies accurately.
Published: 2020

45. Nuclear structure studies with re-accelerated beams at REX-and HIE-ISOLDE

Author: Reiter, P., Warr, N., Reiter, P., and Warr, N.
Abstract: Nuclear-structure studies with reaccelerated radioactive ion beams at the ISOLDE facility, CERN commenced with the REX-ISOLDE facility and continued after a major upgrade of the facility with the HIE-ISOLDE post-accelerator. The experiments are based on in-beam high-resolution gamma-ray spectroscopy with Miniball, a spectrometer which comprises 24 six-fold segmented, encapsulated high-purity germanium crystals. The Miniball array has been used in Coulomb excitation and transfer-reaction experiments with exotic ion beams of energies up to 10 MeV/u. The investigations cover a wide range of nuclear structure topics which are addressed with beams ranging from beryllium up to heavy radium isotopes. Experimental conditions improved substantially after commissioning of the HIE-ISOLDE project at CERN with higher secondary-beam intensity, higher beam energy and better beam quality. We review the spectroscopy achievements obtained at REX-ISOLDE and first published results from HIE-ISOLDE. (C) 2020 Elsevier B.V. All rights reserved.
Published: 2020

46. Detailed spectroscopy of doubly magic Sn-132

Author: Benito, J., Fraile, L. M., Korgul, A., Piersa, M., Adamska, E., Andreyev, A. N., Alvarez-Rodriguez, R., Barzakh, A. E., Benzoni, G., Berry, T., Borge, M. J. G., Carmona, M., Chrysalidis, K., Costache, C., Cubiss, J. G., Goodacre, T. Day, De Witte, H., Fedorov, D., V, Fedosseev, V. N., Fernandez-Martinez, G., Fijalkowska, A., Fila, M., Fynbo, H., Galaviz, D., Galve, P., Garcia-Diez, M., Greenlees, P. T., Grzywacz, R., Harkness-Brennan, L. J., Henrich, C., Huyse, M., Ibanez, P., Illana, A., Janas, Z., Jolie, J., Judson, D. S., Karayonchev, V, Kicinska-Habior, M., Konki, J., Kurcewicz, J., Lazarus, I, Lica, R., Lopez-Montes, A., Lund, M., Mach, H., Madurga, M., Marroquin, I, Marsh, B., Martinez, M. C., Mazzocchi, C., Marginean, N., Marginean, R., Miernik, K., Mihai, C., Mihai, R. E., Nacher, E., Negret, A., Olaizola, B., Page, R. D., Paulauskas, S., V, Pascu, S., Perea, A., Pucknell, V, Rahkila, P., Raison, C., Rapisarda, E., Regis, J-M, Rezynkina, K., Rotaru, F., Rothe, S., Sanchez-Parcerisa, D., Sanchez-Tembleque, V, Schomacker, K., Simpson, G. S., Sotty, Ch, Stan, L., Stanoiu, M., Stryjczyk, M., Tengblad, O., Turturica, A., Udias, J. M., Van Duppen, P., Vedia, V., Villa-Abaunza, A., Vinals, S., Walters, W. B., Wadsworth, R., Warr, N., Benito, J., Fraile, L. M., Korgul, A., Piersa, M., Adamska, E., Andreyev, A. N., Alvarez-Rodriguez, R., Barzakh, A. E., Benzoni, G., Berry, T., Borge, M. J. G., Carmona, M., Chrysalidis, K., Costache, C., Cubiss, J. G., Goodacre, T. Day, De Witte, H., Fedorov, D., V, Fedosseev, V. N., Fernandez-Martinez, G., Fijalkowska, A., Fila, M., Fynbo, H., Galaviz, D., Galve, P., Garcia-Diez, M., Greenlees, P. T., Grzywacz, R., Harkness-Brennan, L. J., Henrich, C., Huyse, M., Ibanez, P., Illana, A., Janas, Z., Jolie, J., Judson, D. S., Karayonchev, V, Kicinska-Habior, M., Konki, J., Kurcewicz, J., Lazarus, I, Lica, R., Lopez-Montes, A., Lund, M., Mach, H., Madurga, M., Marroquin, I, Marsh, B., Martinez, M. C., Mazzocchi, C., Marginean, N., Marginean, R., Miernik, K., Mihai, C., Mihai, R. E., Nacher, E., Negret, A., Olaizola, B., Page, R. D., Paulauskas, S., V, Pascu, S., Perea, A., Pucknell, V, Rahkila, P., Raison, C., Rapisarda, E., Regis, J-M, Rezynkina, K., Rotaru, F., Rothe, S., Sanchez-Parcerisa, D., Sanchez-Tembleque, V, Schomacker, K., Simpson, G. S., Sotty, Ch, Stan, L., Stanoiu, M., Stryjczyk, M., Tengblad, O., Turturica, A., Udias, J. M., Van Duppen, P., Vedia, V., Villa-Abaunza, A., Vinals, S., Walters, W. B., Wadsworth, R., and Warr, N.
Abstract: The structure of the doubly magic Sn-132(50)82 has been investigated at the ISOLDE facility at CERN, populated both by the beta(-) decay of In-132 and beta(-)-delayed neutron emission of In-133. The level scheme of Sn-13(2) is greatly expanded with the addition of 68 gamma transitions and 17 levels observed for the first time in the beta decay. The information on the excited structure is completed by new gamma transitions and states populated in the beta-n decay of In-133. Improved delayed neutron emission probabilities are obtained both for In-132 and In-133. Level lifetimes are measured via the advanced time-delayed beta gamma gamma(t) fast-timing method. An interpretation of the level structure is given based on the experimental findings and the particle-hole configurations arising from core excitations both from the N = 82 and Z = 50 shells, leading to positive- and negative-parity particle-hole multiplets. The experimental information provides new data to challenge the theoretical description of Sn-132.
Published: 2020

47. Decay studies of the long-lived states in Tl-186

Author: Stryjczyk, M., Andel, B., Andreyev, A. N., Cubiss, J., Pakarinen, J., Rezynkina, K., Van Duppen, P., Antalic, S., Berry, T., Borge, M. J. G., Clisu, C., Cox, D. M., De Witte, H., Fraile, L. M., Fynbo, H. O. U., Gaffney, L. P., Harkness-Brennan, L. J., Huyse, M., Illana, A., Judson, D. S., Konki, J., Kurcewicz, J., Lazarus, I, Lica, R., Madurga, M., Marginean, N., Marginean, R., Mihai, C., Mosat, P., Nacher, E., Negret, A., Ojala, J., Ovejas, J. D., Page, R. D., Papadakis, P., Pascu, S., Perea, A., Podolyak, Zs, Pucknell, V, Rapisarda, E., Rotaru, F., Sotty, C., Tengblad, O., Vedia, V., Vinals, S., Wadsworth, R., Warr, N., Wrzosek-Lipska, K., Stryjczyk, M., Andel, B., Andreyev, A. N., Cubiss, J., Pakarinen, J., Rezynkina, K., Van Duppen, P., Antalic, S., Berry, T., Borge, M. J. G., Clisu, C., Cox, D. M., De Witte, H., Fraile, L. M., Fynbo, H. O. U., Gaffney, L. P., Harkness-Brennan, L. J., Huyse, M., Illana, A., Judson, D. S., Konki, J., Kurcewicz, J., Lazarus, I, Lica, R., Madurga, M., Marginean, N., Marginean, R., Mihai, C., Mosat, P., Nacher, E., Negret, A., Ojala, J., Ovejas, J. D., Page, R. D., Papadakis, P., Pascu, S., Perea, A., Podolyak, Zs, Pucknell, V, Rapisarda, E., Rotaru, F., Sotty, C., Tengblad, O., Vedia, V., Vinals, S., Wadsworth, R., Warr, N., and Wrzosek-Lipska, K.
Abstract: Decay spectroscopy of the long-lived states in Tl-186 has been performed at the ISOLDE Decay Station at ISOLDE, CERN. The a decay from the low-spin (2(-)) state in Tl-186 was observed for the first time and a half-life of 3.4(-0.)(4)(+0.5) s was determined. Based on the alpha-decay energy, the relative positions of the long-lived states were fixed, with the (2(-)) state as the ground state, the 7((+)) state at 77(56) keV, and the 10((-)) state at 451(56) keV. The level scheme of the internal decay of the Tl-186(10((-))) state [T-1/2 = 3.40(9) s], which was known to decay solely through emission of 374-keV gamma-ray transition, was extended and a lower limit for the beta-decay branching b(beta) > 5.9(3)% was determined. The extracted retardation factors for the gamma decay of the 10((-) )state were compared to the available data in neighboring odd-odd thallium isotopes indicating the importance of the pi d(3/2) shell in the isomeric decay and significant structure differences between Tl-184 and Tl-186.
Published: 2020

48. Lifetime measurements of excited states in neutron-rich Ti-53: Benchmarking effective shell-model interactions

Author: Goldkuhle, A., Blazhev, A., Fransen, C., Dewald, A., Beckers, M., Birkenbach, B., Braunroth, T., Clement, E., Dudouet, J., Eberth, J., Hess, H., Jacquot, B., Jolie, J., Kim, Y-H, Lemasson, A., Lenzi, S. M., Li, H. J., Litzinger, J., Michelagnoli, C., Mueller-Gatermann, C., Singh, B. S. Nara, Perez-Vidal, R. M., Ralet, D., Reiter, P., Vogt, A., Warr, N., Zell, K. O., Goldkuhle, A., Blazhev, A., Fransen, C., Dewald, A., Beckers, M., Birkenbach, B., Braunroth, T., Clement, E., Dudouet, J., Eberth, J., Hess, H., Jacquot, B., Jolie, J., Kim, Y-H, Lemasson, A., Lenzi, S. M., Li, H. J., Litzinger, J., Michelagnoli, C., Mueller-Gatermann, C., Singh, B. S. Nara, Perez-Vidal, R. M., Ralet, D., Reiter, P., Vogt, A., Warr, N., and Zell, K. O.
Abstract: Level lifetimes of the yrast (5/2(-)) to 13/2(-) states in the neutron-rich nucleus Ti-53, produced in a multinucleon-transfer reaction, have been measured for the first time. The recoil distance Doppler-shift method was employed and lifetimes of the excited states were extracted by a lineshape analysis aided by GEANT4-based Monte-Carlo simulations. The experiment was performed at the Grand Accelerateur National d'Ions Lourds facility in Caen, France, by using the Advanced Gamma Tracking Array for the gamma-ray detection coupled to the large-acceptance variable mode spectrometer for an event-by-event particle identification and the Cologne plunger for deep-inelastic reactions. Reduced transition probabilities, deduced from the lifetimes, give new information on the nuclear structure of Ti-53, and are used to benchmark different shell-model calculations using established interactions in the f p shell.
Published: 2020

49. Restoring the valence-shell stabilization in Nd-140

Author: Kern, R., Zidarova, R., Pietralla, N., Rainovski, G., Stegmann, R., Blazhev, A., Boukhari, A., Cederkall, J., Cubiss, J. G., Djongolov, M., Fransen, C., Gaffney, L. P., Gladnishki, K., Giannopoulos, E., Hess, H., Jolie, J., Karayonchev, V, Kaya, L., Keatings, J. M., Kocheva, D., Kroell, Th, Moeller, O., O'Neill, G. G., Pakarinen, J., Reiter, P., Rosiak, D., Scheck, M., Snall, J., Soederstroem, P-A, Spagnoletti, P., Stoyanova, M., Thiel, S., Vogt, A., Warr, N., Welker, A., Werner, V, Wiederhold, J., De Witte, H., Kern, R., Zidarova, R., Pietralla, N., Rainovski, G., Stegmann, R., Blazhev, A., Boukhari, A., Cederkall, J., Cubiss, J. G., Djongolov, M., Fransen, C., Gaffney, L. P., Gladnishki, K., Giannopoulos, E., Hess, H., Jolie, J., Karayonchev, V, Kaya, L., Keatings, J. M., Kocheva, D., Kroell, Th, Moeller, O., O'Neill, G. G., Pakarinen, J., Reiter, P., Rosiak, D., Scheck, M., Snall, J., Soederstroem, P-A, Spagnoletti, P., Stoyanova, M., Thiel, S., Vogt, A., Warr, N., Welker, A., Werner, V, Wiederhold, J., and De Witte, H.
Abstract: A projectile Coulomb-excitation experiment was performed at the radioactive-ion beam facility HIE-ISOLDE at CERN to obtain E2 and M1 transition matrix elements of Nd-140 using the multistep Coulomb-excitation code GOSIA. The absolute M1 strengths, B(M1; 2(2)(-) -> 2(1)(+)) = 0.033(8)mu(2)(N), B(M1 ; 2(3)(+) -> 2(1)(+)) = 0.26(-0.10)(+0.11)mu(2)(N), and B(M1; 2(4)+ -> 2(1)(+)) < 0.04 mu(2)(N) identify the 2(3)(+) state as the main fragment of the one-quadrupole-phonon proton-neutron mixed-symmetry state of Nd-140. The degree of F-spin mixing in Nd-140 was quantified with the determination of the mixing matrix element VF-mix < 7(-7)(-13) keV.
Published: 2020

50. Lifetime measurements in the odd-A nucleus Hf-177

Author: Knafla, Lukas, Alexa, P., Koester, U., Thiamova, G., Regis, J-M, Jolie, J., Blanc, A., Bruce, A. M., Esmaylzadeh, A., Fraile, L. M., de France, G., Haefner, G., Ilieva, S., Jentschel, M., Karayonchev, V, Korten, W., Kroell, T., Lalkovski, S., Leoni, S., Mach, H., Marginean, N., Mutti, P., Pascovici, G., Paziy, V, Podolyak, Zs, Regan, P. H., Roberts, O. J., Saed-Samii, N., Simpson, G. S., Smith, J. F., Soldner, T., Townsley, C., Ur, C. A., Urban, W., Vancraeyenest, A., Warr, N., Knafla, Lukas, Alexa, P., Koester, U., Thiamova, G., Regis, J-M, Jolie, J., Blanc, A., Bruce, A. M., Esmaylzadeh, A., Fraile, L. M., de France, G., Haefner, G., Ilieva, S., Jentschel, M., Karayonchev, V, Korten, W., Kroell, T., Lalkovski, S., Leoni, S., Mach, H., Marginean, N., Mutti, P., Pascovici, G., Paziy, V, Podolyak, Zs, Regan, P. H., Roberts, O. J., Saed-Samii, N., Simpson, G. S., Smith, J. F., Soldner, T., Townsley, C., Ur, C. A., Urban, W., Vancraeyenest, A., and Warr, N.
Abstract: Lifetimes of low- and high-spin states in the odd-A nucleus Hf-177 were measured during the EXILL&FATIMA campaign using a spectrometer equipped with eight HPGe-Clover detectors and 16 fast-timing LaBr3(Ce) detectors. For the determination of lifetimes in the pico- to nanosecond regime, the well-established generalized centroid difference method was used. Lifetimes of the 9/2(-), 9/2(+), 11/2(-), 11/2(+) states were remeasured, the lifetimes of the 13/2(-), 17/2(-), 13/2(+), 15/2(+), and 17/2(+) states were determined for the first time and an upper limit for the 19/2(+) state has been established. From these lifetimes absolute reduced transition probabilities were extracted and compared to particle-rotor-model calculations and quasiparticle-phonon-model calculations showing the importance of including multipole-multipole interactions in the description of odd-A nuclei in the rare earth region.
Published: 2020

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