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1. Pseudospin Symmetry and Microscopic Origin of Shape Coexistence in the Ni-78 Region : A Hint from Lifetime Measurements

Author

Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, Johan, Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, Dobon, J. J. Valiente, Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, Johan, Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, and Dobon, J. J. Valiente

Abstract

Lifetime measurements of excited states of the light N = 52 isotones Kr-88, Se-86, and Ge-84 have been performed, using the recoil distance Doppler shift method and VAMOS and AGATA spectrometers for particle identification and gamma spectroscopy, respectively. The reduced electric quadrupole transition probabilities B(E2; 2(+)-> 0(+)) and B(E2; 4(+)-> 2(+)) were obtained for the first time for the hard-to-reach 84Ge. While the B(E2; 2(+)-> 0(+) ) values of Kr-88, Se-86 saturate the maximum quadrupole collectivity offered by the natural valence (3s, 2d, 1g(7/2), 1h(11/2)) space of an inert Ni-78 core, the value obtained for Ge-84 largely exceeds it, suggesting that shape coexistence phenomena, previously reported at N less than or similar to 49, extend beyond N = 50. The onset of collectivity at Z = 32 is understood as due to a pseudo-SU(3) organization of the proton single-particle sequence reflecting a clear manifestation of pseudospin symmetry. It is realized that the latter provides actually reliable guidance for understanding the observed proton and neutron single particle structure in the whole medium-mass region, from Ni to Sn, pointing towards the important role of the isovector-vector rho field in shell-structure evolution.

Published
2018
Full Text
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2. Pseudospin Symmetry and Microscopic Origin of Shape Coexistence in the Ni-78 Region : A Hint from Lifetime Measurements

Author

Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, Johan, Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, Dobon, J. J. Valiente, Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, Johan, Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, and Dobon, J. J. Valiente

Abstract

Lifetime measurements of excited states of the light N = 52 isotones Kr-88, Se-86, and Ge-84 have been performed, using the recoil distance Doppler shift method and VAMOS and AGATA spectrometers for particle identification and gamma spectroscopy, respectively. The reduced electric quadrupole transition probabilities B(E2; 2(+)-> 0(+)) and B(E2; 4(+)-> 2(+)) were obtained for the first time for the hard-to-reach 84Ge. While the B(E2; 2(+)-> 0(+) ) values of Kr-88, Se-86 saturate the maximum quadrupole collectivity offered by the natural valence (3s, 2d, 1g(7/2), 1h(11/2)) space of an inert Ni-78 core, the value obtained for Ge-84 largely exceeds it, suggesting that shape coexistence phenomena, previously reported at N less than or similar to 49, extend beyond N = 50. The onset of collectivity at Z = 32 is understood as due to a pseudo-SU(3) organization of the proton single-particle sequence reflecting a clear manifestation of pseudospin symmetry. It is realized that the latter provides actually reliable guidance for understanding the observed proton and neutron single particle structure in the whole medium-mass region, from Ni to Sn, pointing towards the important role of the isovector-vector rho field in shell-structure evolution.

Published
2018
Full Text
View/download PDF

3. Pseudospin Symmetry and Microscopic Origin of Shape Coexistence in the Ni-78 Region : A Hint from Lifetime Measurements

Author

Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, Johan, Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, Dobon, J. J. Valiente, Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, Johan, Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, and Dobon, J. J. Valiente

Abstract

Lifetime measurements of excited states of the light N = 52 isotones Kr-88, Se-86, and Ge-84 have been performed, using the recoil distance Doppler shift method and VAMOS and AGATA spectrometers for particle identification and gamma spectroscopy, respectively. The reduced electric quadrupole transition probabilities B(E2; 2(+)-> 0(+)) and B(E2; 4(+)-> 2(+)) were obtained for the first time for the hard-to-reach 84Ge. While the B(E2; 2(+)-> 0(+) ) values of Kr-88, Se-86 saturate the maximum quadrupole collectivity offered by the natural valence (3s, 2d, 1g(7/2), 1h(11/2)) space of an inert Ni-78 core, the value obtained for Ge-84 largely exceeds it, suggesting that shape coexistence phenomena, previously reported at N less than or similar to 49, extend beyond N = 50. The onset of collectivity at Z = 32 is understood as due to a pseudo-SU(3) organization of the proton single-particle sequence reflecting a clear manifestation of pseudospin symmetry. It is realized that the latter provides actually reliable guidance for understanding the observed proton and neutron single particle structure in the whole medium-mass region, from Ni to Sn, pointing towards the important role of the isovector-vector rho field in shell-structure evolution.

Published
2018
Full Text
View/download PDF

4. Pseudospin Symmetry and Microscopic Origin of Shape Coexistence in the Ni-78 Region: A Hint from Lifetime Measurements

Author

Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, J., Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, Dobon, J. J. Valiente, Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, J., Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, and Dobon, J. J. Valiente

Abstract

Lifetime measurements of excited states of the light N = 52 isotones Kr-88, Se-86, and Ge-84 have been performed, using the recoil distance Doppler shift method and VAMOS and AGATA spectrometers for particle identification and gamma spectroscopy, respectively. The reduced electric quadrupole transition probabilities B(E2; 2(+)-> 0(+)) and B(E2; 4(+)-> 2(+)) were obtained for the first time for the hard-to-reach 84Ge. While the B(E2; 2(+)-> 0(+) ) values of Kr-88, Se-86 saturate the maximum quadrupole collectivity offered by the natural valence (3s, 2d, 1g(7/2), 1h(11/2)) space of an inert Ni-78 core, the value obtained for Ge-84 largely exceeds it, suggesting that shape coexistence phenomena, previously reported at N less than or similar to 49, extend beyond N = 50. The onset of collectivity at Z = 32 is understood as due to a pseudo-SU(3) organization of the proton single-particle sequence reflecting a clear manifestation of pseudospin symmetry. It is realized that the latter provides actually reliable guidance for understanding the observed proton and neutron single particle structure in the whole medium-mass region, from Ni to Sn, pointing towards the important role of the isovector-vector rho field in shell-structure evolution.

Published
2018

5. Pseudospin Symmetry and Microscopic Origin of Shape Coexistence in the Ni-78 Region : A Hint from Lifetime Measurements

Author

Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, Johan, Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, Dobon, J. J. Valiente, Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, Johan, Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, and Dobon, J. J. Valiente

Abstract

Lifetime measurements of excited states of the light N = 52 isotones Kr-88, Se-86, and Ge-84 have been performed, using the recoil distance Doppler shift method and VAMOS and AGATA spectrometers for particle identification and gamma spectroscopy, respectively. The reduced electric quadrupole transition probabilities B(E2; 2(+)-> 0(+)) and B(E2; 4(+)-> 2(+)) were obtained for the first time for the hard-to-reach 84Ge. While the B(E2; 2(+)-> 0(+) ) values of Kr-88, Se-86 saturate the maximum quadrupole collectivity offered by the natural valence (3s, 2d, 1g(7/2), 1h(11/2)) space of an inert Ni-78 core, the value obtained for Ge-84 largely exceeds it, suggesting that shape coexistence phenomena, previously reported at N less than or similar to 49, extend beyond N = 50. The onset of collectivity at Z = 32 is understood as due to a pseudo-SU(3) organization of the proton single-particle sequence reflecting a clear manifestation of pseudospin symmetry. It is realized that the latter provides actually reliable guidance for understanding the observed proton and neutron single particle structure in the whole medium-mass region, from Ni to Sn, pointing towards the important role of the isovector-vector rho field in shell-structure evolution.

Published
2018
Full Text
View/download PDF

6. Pseudospin Symmetry and Microscopic Origin of Shape Coexistence in the Ni-78 Region: A Hint from Lifetime Measurements

Author

Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, J., Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, Dobon, J. J. Valiente, Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, J., Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, and Dobon, J. J. Valiente

Abstract

Lifetime measurements of excited states of the light N = 52 isotones Kr-88, Se-86, and Ge-84 have been performed, using the recoil distance Doppler shift method and VAMOS and AGATA spectrometers for particle identification and gamma spectroscopy, respectively. The reduced electric quadrupole transition probabilities B(E2; 2(+)-> 0(+)) and B(E2; 4(+)-> 2(+)) were obtained for the first time for the hard-to-reach 84Ge. While the B(E2; 2(+)-> 0(+) ) values of Kr-88, Se-86 saturate the maximum quadrupole collectivity offered by the natural valence (3s, 2d, 1g(7/2), 1h(11/2)) space of an inert Ni-78 core, the value obtained for Ge-84 largely exceeds it, suggesting that shape coexistence phenomena, previously reported at N less than or similar to 49, extend beyond N = 50. The onset of collectivity at Z = 32 is understood as due to a pseudo-SU(3) organization of the proton single-particle sequence reflecting a clear manifestation of pseudospin symmetry. It is realized that the latter provides actually reliable guidance for understanding the observed proton and neutron single particle structure in the whole medium-mass region, from Ni to Sn, pointing towards the important role of the isovector-vector rho field in shell-structure evolution.

Published
2018

7. Pseudospin Symmetry and Microscopic Origin of Shape Coexistence in the Ni-78 Region : A Hint from Lifetime Measurements

Author

Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, Johan, Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, Dobon, J. J. Valiente, Delafosse, C., Verney, D., Marevic, P., Gottardo, A., Michelagnoli, C., Lemasson, A., Goasduff, A., Ljungvall, J., Clement, E., Korichi, A., De Angelis, G., Andreoiu, C., Babo, M., Boso, A., Didierjean, F., Dudouet, J., Franchoo, S., Gadea, A., Georgiev, G., Ibrahim, F., Jacquot, B., Konstantinopoulos, T., Lenzi, S. M., Maquart, G., Matea, I, Mengoni, D., Napoli, D. R., Niksic, T., Olivier, L., Perez-Vidal, R. M., Portail, C., Recchia, F., Redon, N., Siciliano, M., Stefan, I, Stezowski, O., Vretenar, D., Zielinska, M., Barrientos, D., Benzoni, G., Birkenbach, B., Boston, A. J., Boston, H. C., Cederwall, B., Charles, L., Ciemala, M., Collado, J., Cullen, D. M., Desesquelles, P., de France, G., Domingo-Pardo, C., Eberth, J., Gonzalez, V, Harkness-Brennan, L. J., Hess, H., Judson, D. S., Jungclaus, A., Korten, W., Lefevre, A., Legruel, F., Menegazzo, R., Million, B., Nyberg, Johan, Quintana, B., Ralet, D., Reiter, P., Saillant, F., Sanchis, E., Theisen, Ch, and Dobon, J. J. Valiente

Abstract

Lifetime measurements of excited states of the light N = 52 isotones Kr-88, Se-86, and Ge-84 have been performed, using the recoil distance Doppler shift method and VAMOS and AGATA spectrometers for particle identification and gamma spectroscopy, respectively. The reduced electric quadrupole transition probabilities B(E2; 2(+)-> 0(+)) and B(E2; 4(+)-> 2(+)) were obtained for the first time for the hard-to-reach 84Ge. While the B(E2; 2(+)-> 0(+) ) values of Kr-88, Se-86 saturate the maximum quadrupole collectivity offered by the natural valence (3s, 2d, 1g(7/2), 1h(11/2)) space of an inert Ni-78 core, the value obtained for Ge-84 largely exceeds it, suggesting that shape coexistence phenomena, previously reported at N less than or similar to 49, extend beyond N = 50. The onset of collectivity at Z = 32 is understood as due to a pseudo-SU(3) organization of the proton single-particle sequence reflecting a clear manifestation of pseudospin symmetry. It is realized that the latter provides actually reliable guidance for understanding the observed proton and neutron single particle structure in the whole medium-mass region, from Ni to Sn, pointing towards the important role of the isovector-vector rho field in shell-structure evolution.

Published
2018
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8. Measurement of lifetimes in Fe-62,Fe-64, Co-61,Co-63, and Mn-59

Author

Klintefjord, M., Ljungvall, J., Gorgen, A., Lenzi, S. M., Garrote, F. L. Bello, Blazhev, A., Clement, E., de France, G., Delaroche, J. -P., Desesquelles, P., Dewald, A., Doherty, D. T., Fransen, C., Gengelbach, A., Georgiev, G., Girod, M., Goasduff, A., Gottardo, A., Hadynska-Klek, K., Jacquot, B., Konstantinopoulos, T., Korichi, A., Lemasson, A., Libert, J., Lopez-Martens, A., Michelagnoli, C., Navin, A., Nyberg, J., Perez-Vidal, R. M., Roccia, S., Sahin, E., Stefan, I., Stuchbery, A. E., Zielinska, M., Barrientos, D., Birkenbach, B., Boston, A., Charles, L., Ciemala, M., Dudouet, J., Eberth, J., Gadea, A., Gonzalez, V., Harkness-Brennan, L., Hess, H., Jungclaus, A., Korten, W., Menegazzo, R., Mengoni, D., Million, B., Pullia, A., Ralet, D., Recchia, F., Reiter, P., Salsac, M. D., Sanchis, E., Stezowski, O., Theisen, Ch., Dobon, J. J. Valiente, Klintefjord, M., Ljungvall, J., Gorgen, A., Lenzi, S. M., Garrote, F. L. Bello, Blazhev, A., Clement, E., de France, G., Delaroche, J. -P., Desesquelles, P., Dewald, A., Doherty, D. T., Fransen, C., Gengelbach, A., Georgiev, G., Girod, M., Goasduff, A., Gottardo, A., Hadynska-Klek, K., Jacquot, B., Konstantinopoulos, T., Korichi, A., Lemasson, A., Libert, J., Lopez-Martens, A., Michelagnoli, C., Navin, A., Nyberg, J., Perez-Vidal, R. M., Roccia, S., Sahin, E., Stefan, I., Stuchbery, A. E., Zielinska, M., Barrientos, D., Birkenbach, B., Boston, A., Charles, L., Ciemala, M., Dudouet, J., Eberth, J., Gadea, A., Gonzalez, V., Harkness-Brennan, L., Hess, H., Jungclaus, A., Korten, W., Menegazzo, R., Mengoni, D., Million, B., Pullia, A., Ralet, D., Recchia, F., Reiter, P., Salsac, M. D., Sanchis, E., Stezowski, O., Theisen, Ch., and Dobon, J. J. Valiente

Abstract

Lifetimes of the 4(1)(+) states in Fe-62,Fe-64 and the 11/2(1)(-) states in Co-61,Co-63 and Mn-59 were measured at the Grand Accelerateur National d'Ions Lourds (GANIL) facility by using the Advanced Gamma Tracking Array (AGATA) and the large-acceptance variable mode spectrometer (VAMOS++). The states were populated through multinucleon transfer reactions with a U-238 beam impinging on a Ni-64 target, and lifetimes in the picosecond range were measured by using the recoil distance Doppler shift method. The data show an increase of collectivity in the iron isotopes approaching N = 40. The reduction of the subshell gap between the nu 2p(1/2) and nu 1g(9/2) orbitals leads to an increased population of the quasi-SU(3) pair (nu 1g(9/2), nu 2d(5/2)), which causes an increase in quadrupole collectivity. This is not observed for the cobalt isotopes withN < 40 for which the neutron subshell gap is larger due to the repulsive monopole component of the tensor nucleon-nucleon interaction. The extracted experimental B(E2) values are compared with large-scale shell-model calculations and with beyond-mean-field calculations with the Gogny D1S interaction. A good agreement between calculations and experimental values is found, and the results demonstrate in particular the spectroscopic quality of the Lenzi, Nowacki, Poves, and Sieja (LNPS) shell-model interaction.

Published
2017

9. Lifetime measurements in Ru-100

Author

Konstantinopoulos, T., Petkov, P., Goasduff, A., Arici, T., Astier, A., Atanasova, L., Axiotis, M., Bonatsos, D., Detistov, P., Dewald, A., Eller, M. J., Foteinou, V., Gargano, A., Georgiev, G., Gladnishki, K., Gottardo, A., Harissopulos, S., Hess, H., Kaim, S., Kocheva, D., Kusoglu, A., Lagoyannis, A., Ljungvall, J., Lutter, R., Matea, I., Melon, B., Mertzimekis, T. J., Nannini, A., Petrache, C. M., Petrovici, A., Provatas, G., Reiter, P., Rocchini, M., Roccia, S., Seidlitz, M., Siebeck, B., Suzuki, D., Warr, N., De Witte, H., Zerrouki, T., Konstantinopoulos, T., Petkov, P., Goasduff, A., Arici, T., Astier, A., Atanasova, L., Axiotis, M., Bonatsos, D., Detistov, P., Dewald, A., Eller, M. J., Foteinou, V., Gargano, A., Georgiev, G., Gladnishki, K., Gottardo, A., Harissopulos, S., Hess, H., Kaim, S., Kocheva, D., Kusoglu, A., Lagoyannis, A., Ljungvall, J., Lutter, R., Matea, I., Melon, B., Mertzimekis, T. J., Nannini, A., Petrache, C. M., Petrovici, A., Provatas, G., Reiter, P., Rocchini, M., Roccia, S., Seidlitz, M., Siebeck, B., Suzuki, D., Warr, N., De Witte, H., and Zerrouki, T.

Abstract

The nucleus Ru-100 appears to be a good candidate for the E(5) critical point symmetry which describes the U(5)-SO(6) shape phase transition. To investigate this point with respect to the electromagnetic transition strengths, lifetime measurements of its yrast states have been performed using the recoil distance Doppler shift technique as well as the Doppler shift attenuation method. As a result, the lifetimes of the yrast 2(+), 4(+), and 8(+) states were determined. The deduced transition strengths are compared to the E(5) predictions as well as to the results of excited Vampir and shell-model calculations.

Published
2017

10. Kr-96(36)60-Low-Z Boundary of the Island of Deformation at N=60

Author

Dudouet, J., Lemasson, A., Duchene, G., Rejmund, M., Clement, E., Michelagnoli, C., Didierjean, F., Korichi, A., Maquart, G., Stezowski, O., Lizarazo, C., Perez-Vidal, R. M., Andreoiu, C., de Angelis, G., Astier, A., Delafosse, C., Deloncle, I., Dombradi, Z., de France, G., Gadea, A., Gottardo, A., Jacquot, B., Jones, P., Konstantinopoulos, T., Kuti, I., Le Blanc, F., Lenzi, S. M., Li, G., Lozeva, R., Million, B., Napoli, D. R., Navin, A., Petrache, C. M., Pietralla, N., Ralet, D., Ramdhane, M., Redon, N., Schmitt, C., Sohler, D., Verney, D., Barrientos, D., Birkenbach, B., Burrows, I., Charles, L., CoIlado, J., Cullen, D. M., Desesquelles, P., Domingo Pardo, C., Gonzalez, V., Harkness-Brennan, L., Hess, H., Judson, D. S., Karolak, M., Korten, W., Labiche, M., Ljungval, J., Menegazzo, R., Mengoni, D., Pullia, A., Recchia, F., Reiter, P., Salsac, M. D., Sanchis, E., Theisen, Ch., Valiente-Dobon, J. J., Zielinska, M., Dudouet, J., Lemasson, A., Duchene, G., Rejmund, M., Clement, E., Michelagnoli, C., Didierjean, F., Korichi, A., Maquart, G., Stezowski, O., Lizarazo, C., Perez-Vidal, R. M., Andreoiu, C., de Angelis, G., Astier, A., Delafosse, C., Deloncle, I., Dombradi, Z., de France, G., Gadea, A., Gottardo, A., Jacquot, B., Jones, P., Konstantinopoulos, T., Kuti, I., Le Blanc, F., Lenzi, S. M., Li, G., Lozeva, R., Million, B., Napoli, D. R., Navin, A., Petrache, C. M., Pietralla, N., Ralet, D., Ramdhane, M., Redon, N., Schmitt, C., Sohler, D., Verney, D., Barrientos, D., Birkenbach, B., Burrows, I., Charles, L., CoIlado, J., Cullen, D. M., Desesquelles, P., Domingo Pardo, C., Gonzalez, V., Harkness-Brennan, L., Hess, H., Judson, D. S., Karolak, M., Korten, W., Labiche, M., Ljungval, J., Menegazzo, R., Mengoni, D., Pullia, A., Recchia, F., Reiter, P., Salsac, M. D., Sanchis, E., Theisen, Ch., Valiente-Dobon, J. J., and Zielinska, M.

Abstract

Prompt.-ray spectroscopy of the neutron-rich Kr-96, produced in transfer-and fusion-induced fission reactions, has been performed using the combination of the Advanced Gamma Tracking Array and the VAMOS + +spectrometer. A second excited state, assigned to J pi = 4(+), is observed for the first time, and a previously reported level energy of the first 2+ excited state is confirmed. The measured energy ratio R-4/2 = E(4(+))/E(2(+)) = 2.12(1) indicates that this nucleus does not show a well-developed collectivity contrary to that seen in heavier N = 60 isotones. This new measurement highlights an abrupt transition of the degree of collectivity as a function of the proton number at Z = 36, of similar amplitude to that observed at N = 60 at higher Z values. A possible reason for this abrupt transition could be related to the insufficient proton excitations in the g(9/2), d(5/2), and s(1/2) orbitals to generate strong quadrupole correlations or to the coexistence of competing different shapes. An unexpected continuous decrease of R-4/2 as a function of the neutron number up to N = 60 is also evidenced. This measurement establishes the Kr isotopic chain as the low-Z boundary of the island of deformation for N = 60 isotones. A comparison with available theoretical predictions using different beyond mean-field approaches shows that these models fail to reproduce the abrupt transitions at N = 60 and Z = 36.

Published
2017

11. Anomalies in the Charge Yields of Fission Fragments from the U-238(n, f) Reaction

Author

Wilson, J. N., Lebois, M., Qi, L., Amador-Celdran, P., Bleuel, D., Briz, J. A., Carroll, R., Catford, W., De Witte, H., Doherty, D. T., Eloirdi, R., Georgiev, G., Gottardo, A., Goasduff, A., Hadynska-Klek, K., Hauschild, K., Hess, H., Ingeberg, V., Konstantinopoulos, T., Ljungvall, J., Lopez-Martens, A., Lorusso, G., Lozeva, R., Lutter, R., Marini, P., Matea, I., Materna, T., Mathieu, L., Oberstedt, A., Oberstedt, S., Panebianco, S., Podolyak, Zs., Porta, A., Regan, P. H., Reiter, P., Rezynkina, K., Rose, S. J., Sahin, E., Seidlitz, M., Serot, O., Shearman, R., Siebeck, B., Siem, S., Smith, A. G., Tveten, G. M., Verney, D., Warr, N., Zeiser, F., Zielinska, M., Wilson, J. N., Lebois, M., Qi, L., Amador-Celdran, P., Bleuel, D., Briz, J. A., Carroll, R., Catford, W., De Witte, H., Doherty, D. T., Eloirdi, R., Georgiev, G., Gottardo, A., Goasduff, A., Hadynska-Klek, K., Hauschild, K., Hess, H., Ingeberg, V., Konstantinopoulos, T., Ljungvall, J., Lopez-Martens, A., Lorusso, G., Lozeva, R., Lutter, R., Marini, P., Matea, I., Materna, T., Mathieu, L., Oberstedt, A., Oberstedt, S., Panebianco, S., Podolyak, Zs., Porta, A., Regan, P. H., Reiter, P., Rezynkina, K., Rose, S. J., Sahin, E., Seidlitz, M., Serot, O., Shearman, R., Siebeck, B., Siem, S., Smith, A. G., Tveten, G. M., Verney, D., Warr, N., Zeiser, F., and Zielinska, M.

Abstract

Fast-neutron-induced fission of U-238 at an energy just above the fission threshold is studied with a novel technique which involves the coupling of a high-efficiency.-ray spectrometer (MINIBALL) to an inversekinematics neutron source (LICORNE) to extract charge yields of fission fragments via gamma-gamma coincidence spectroscopy. Experimental data and fission models are compared and found to be in reasonable agreement for many nuclei; however, significant discrepancies of up to 600% are observed, particularly for isotopes of Sn and Mo. This indicates that these models significantly overestimate the standard 1 fission mode and suggests that spherical shell effects in the nascent fission fragments are less important for low-energy fastneutron-induced fission than for thermal neutron-induced fission. This has consequences for understanding and modeling the fission process, for experimental nuclear structure studies of the most neutron-rich nuclei, for future energy applications (e.g., Generation IV reactors which use fast-neutron spectra), and for the reactor antineutrino anomaly.

Published
2017

12. Lifetime measurements in Ru-100

Author

Konstantinopoulos, T., Petkov, P., Goasduff, A., Arici, T., Astier, A., Atanasova, L., Axiotis, M., Bonatsos, D., Detistov, P., Dewald, A., Eller, M. J., Foteinou, V., Gargano, A., Georgiev, G., Gladnishki, K., Gottardo, A., Harissopulos, S., Hess, H., Kaim, S., Kocheva, D., Kusoglu, A., Lagoyannis, A., Ljungvall, J., Lutter, R., Matea, I., Melon, B., Mertzimekis, T. J., Nannini, A., Petrache, C. M., Petrovici, A., Provatas, G., Reiter, P., Rocchini, M., Roccia, S., Seidlitz, M., Siebeck, B., Suzuki, D., Warr, N., De Witte, H., Zerrouki, T., Konstantinopoulos, T., Petkov, P., Goasduff, A., Arici, T., Astier, A., Atanasova, L., Axiotis, M., Bonatsos, D., Detistov, P., Dewald, A., Eller, M. J., Foteinou, V., Gargano, A., Georgiev, G., Gladnishki, K., Gottardo, A., Harissopulos, S., Hess, H., Kaim, S., Kocheva, D., Kusoglu, A., Lagoyannis, A., Ljungvall, J., Lutter, R., Matea, I., Melon, B., Mertzimekis, T. J., Nannini, A., Petrache, C. M., Petrovici, A., Provatas, G., Reiter, P., Rocchini, M., Roccia, S., Seidlitz, M., Siebeck, B., Suzuki, D., Warr, N., De Witte, H., and Zerrouki, T.

Abstract

The nucleus Ru-100 appears to be a good candidate for the E(5) critical point symmetry which describes the U(5)-SO(6) shape phase transition. To investigate this point with respect to the electromagnetic transition strengths, lifetime measurements of its yrast states have been performed using the recoil distance Doppler shift technique as well as the Doppler shift attenuation method. As a result, the lifetimes of the yrast 2(+), 4(+), and 8(+) states were determined. The deduced transition strengths are compared to the E(5) predictions as well as to the results of excited Vampir and shell-model calculations.

Published
2017

13. Measurement of lifetimes in Fe-62,Fe-64, Co-61,Co-63, and Mn-59

Author

Klintefjord, M., Ljungvall, J., Gorgen, A., Lenzi, S. M., Garrote, F. L. Bello, Blazhev, A., Clement, E., de France, G., Delaroche, J. -P., Desesquelles, P., Dewald, A., Doherty, D. T., Fransen, C., Gengelbach, A., Georgiev, G., Girod, M., Goasduff, A., Gottardo, A., Hadynska-Klek, K., Jacquot, B., Konstantinopoulos, T., Korichi, A., Lemasson, A., Libert, J., Lopez-Martens, A., Michelagnoli, C., Navin, A., Nyberg, J., Perez-Vidal, R. M., Roccia, S., Sahin, E., Stefan, I., Stuchbery, A. E., Zielinska, M., Barrientos, D., Birkenbach, B., Boston, A., Charles, L., Ciemala, M., Dudouet, J., Eberth, J., Gadea, A., Gonzalez, V., Harkness-Brennan, L., Hess, H., Jungclaus, A., Korten, W., Menegazzo, R., Mengoni, D., Million, B., Pullia, A., Ralet, D., Recchia, F., Reiter, P., Salsac, M. D., Sanchis, E., Stezowski, O., Theisen, Ch., Dobon, J. J. Valiente, Klintefjord, M., Ljungvall, J., Gorgen, A., Lenzi, S. M., Garrote, F. L. Bello, Blazhev, A., Clement, E., de France, G., Delaroche, J. -P., Desesquelles, P., Dewald, A., Doherty, D. T., Fransen, C., Gengelbach, A., Georgiev, G., Girod, M., Goasduff, A., Gottardo, A., Hadynska-Klek, K., Jacquot, B., Konstantinopoulos, T., Korichi, A., Lemasson, A., Libert, J., Lopez-Martens, A., Michelagnoli, C., Navin, A., Nyberg, J., Perez-Vidal, R. M., Roccia, S., Sahin, E., Stefan, I., Stuchbery, A. E., Zielinska, M., Barrientos, D., Birkenbach, B., Boston, A., Charles, L., Ciemala, M., Dudouet, J., Eberth, J., Gadea, A., Gonzalez, V., Harkness-Brennan, L., Hess, H., Jungclaus, A., Korten, W., Menegazzo, R., Mengoni, D., Million, B., Pullia, A., Ralet, D., Recchia, F., Reiter, P., Salsac, M. D., Sanchis, E., Stezowski, O., Theisen, Ch., and Dobon, J. J. Valiente

Abstract

Lifetimes of the 4(1)(+) states in Fe-62,Fe-64 and the 11/2(1)(-) states in Co-61,Co-63 and Mn-59 were measured at the Grand Accelerateur National d'Ions Lourds (GANIL) facility by using the Advanced Gamma Tracking Array (AGATA) and the large-acceptance variable mode spectrometer (VAMOS++). The states were populated through multinucleon transfer reactions with a U-238 beam impinging on a Ni-64 target, and lifetimes in the picosecond range were measured by using the recoil distance Doppler shift method. The data show an increase of collectivity in the iron isotopes approaching N = 40. The reduction of the subshell gap between the nu 2p(1/2) and nu 1g(9/2) orbitals leads to an increased population of the quasi-SU(3) pair (nu 1g(9/2), nu 2d(5/2)), which causes an increase in quadrupole collectivity. This is not observed for the cobalt isotopes withN < 40 for which the neutron subshell gap is larger due to the repulsive monopole component of the tensor nucleon-nucleon interaction. The extracted experimental B(E2) values are compared with large-scale shell-model calculations and with beyond-mean-field calculations with the Gogny D1S interaction. A good agreement between calculations and experimental values is found, and the results demonstrate in particular the spectroscopic quality of the Lenzi, Nowacki, Poves, and Sieja (LNPS) shell-model interaction.

Published
2017

14. Anomalies in the Charge Yields of Fission Fragments from the U-238(n, f) Reaction

Author

Wilson, J. N., Lebois, M., Qi, L., Amador-Celdran, P., Bleuel, D., Briz, J. A., Carroll, R., Catford, W., De Witte, H., Doherty, D. T., Eloirdi, R., Georgiev, G., Gottardo, A., Goasduff, A., Hadynska-Klek, K., Hauschild, K., Hess, H., Ingeberg, V., Konstantinopoulos, T., Ljungvall, J., Lopez-Martens, A., Lorusso, G., Lozeva, R., Lutter, R., Marini, P., Matea, I., Materna, T., Mathieu, L., Oberstedt, A., Oberstedt, S., Panebianco, S., Podolyak, Zs., Porta, A., Regan, P. H., Reiter, P., Rezynkina, K., Rose, S. J., Sahin, E., Seidlitz, M., Serot, O., Shearman, R., Siebeck, B., Siem, S., Smith, A. G., Tveten, G. M., Verney, D., Warr, N., Zeiser, F., Zielinska, M., Wilson, J. N., Lebois, M., Qi, L., Amador-Celdran, P., Bleuel, D., Briz, J. A., Carroll, R., Catford, W., De Witte, H., Doherty, D. T., Eloirdi, R., Georgiev, G., Gottardo, A., Goasduff, A., Hadynska-Klek, K., Hauschild, K., Hess, H., Ingeberg, V., Konstantinopoulos, T., Ljungvall, J., Lopez-Martens, A., Lorusso, G., Lozeva, R., Lutter, R., Marini, P., Matea, I., Materna, T., Mathieu, L., Oberstedt, A., Oberstedt, S., Panebianco, S., Podolyak, Zs., Porta, A., Regan, P. H., Reiter, P., Rezynkina, K., Rose, S. J., Sahin, E., Seidlitz, M., Serot, O., Shearman, R., Siebeck, B., Siem, S., Smith, A. G., Tveten, G. M., Verney, D., Warr, N., Zeiser, F., and Zielinska, M.

Abstract

Fast-neutron-induced fission of U-238 at an energy just above the fission threshold is studied with a novel technique which involves the coupling of a high-efficiency.-ray spectrometer (MINIBALL) to an inversekinematics neutron source (LICORNE) to extract charge yields of fission fragments via gamma-gamma coincidence spectroscopy. Experimental data and fission models are compared and found to be in reasonable agreement for many nuclei; however, significant discrepancies of up to 600% are observed, particularly for isotopes of Sn and Mo. This indicates that these models significantly overestimate the standard 1 fission mode and suggests that spherical shell effects in the nascent fission fragments are less important for low-energy fastneutron-induced fission than for thermal neutron-induced fission. This has consequences for understanding and modeling the fission process, for experimental nuclear structure studies of the most neutron-rich nuclei, for future energy applications (e.g., Generation IV reactors which use fast-neutron spectra), and for the reactor antineutrino anomaly.

Published
2017

15. Kr-96(36)60-Low-Z Boundary of the Island of Deformation at N=60

Author

Dudouet, J., Lemasson, A., Duchene, G., Rejmund, M., Clement, E., Michelagnoli, C., Didierjean, F., Korichi, A., Maquart, G., Stezowski, O., Lizarazo, C., Perez-Vidal, R. M., Andreoiu, C., de Angelis, G., Astier, A., Delafosse, C., Deloncle, I., Dombradi, Z., de France, G., Gadea, A., Gottardo, A., Jacquot, B., Jones, P., Konstantinopoulos, T., Kuti, I., Le Blanc, F., Lenzi, S. M., Li, G., Lozeva, R., Million, B., Napoli, D. R., Navin, A., Petrache, C. M., Pietralla, N., Ralet, D., Ramdhane, M., Redon, N., Schmitt, C., Sohler, D., Verney, D., Barrientos, D., Birkenbach, B., Burrows, I., Charles, L., CoIlado, J., Cullen, D. M., Desesquelles, P., Domingo Pardo, C., Gonzalez, V., Harkness-Brennan, L., Hess, H., Judson, D. S., Karolak, M., Korten, W., Labiche, M., Ljungval, J., Menegazzo, R., Mengoni, D., Pullia, A., Recchia, F., Reiter, P., Salsac, M. D., Sanchis, E., Theisen, Ch., Valiente-Dobon, J. J., Zielinska, M., Dudouet, J., Lemasson, A., Duchene, G., Rejmund, M., Clement, E., Michelagnoli, C., Didierjean, F., Korichi, A., Maquart, G., Stezowski, O., Lizarazo, C., Perez-Vidal, R. M., Andreoiu, C., de Angelis, G., Astier, A., Delafosse, C., Deloncle, I., Dombradi, Z., de France, G., Gadea, A., Gottardo, A., Jacquot, B., Jones, P., Konstantinopoulos, T., Kuti, I., Le Blanc, F., Lenzi, S. M., Li, G., Lozeva, R., Million, B., Napoli, D. R., Navin, A., Petrache, C. M., Pietralla, N., Ralet, D., Ramdhane, M., Redon, N., Schmitt, C., Sohler, D., Verney, D., Barrientos, D., Birkenbach, B., Burrows, I., Charles, L., CoIlado, J., Cullen, D. M., Desesquelles, P., Domingo Pardo, C., Gonzalez, V., Harkness-Brennan, L., Hess, H., Judson, D. S., Karolak, M., Korten, W., Labiche, M., Ljungval, J., Menegazzo, R., Mengoni, D., Pullia, A., Recchia, F., Reiter, P., Salsac, M. D., Sanchis, E., Theisen, Ch., Valiente-Dobon, J. J., and Zielinska, M.

Abstract

Prompt.-ray spectroscopy of the neutron-rich Kr-96, produced in transfer-and fusion-induced fission reactions, has been performed using the combination of the Advanced Gamma Tracking Array and the VAMOS + +spectrometer. A second excited state, assigned to J pi = 4(+), is observed for the first time, and a previously reported level energy of the first 2+ excited state is confirmed. The measured energy ratio R-4/2 = E(4(+))/E(2(+)) = 2.12(1) indicates that this nucleus does not show a well-developed collectivity contrary to that seen in heavier N = 60 isotones. This new measurement highlights an abrupt transition of the degree of collectivity as a function of the proton number at Z = 36, of similar amplitude to that observed at N = 60 at higher Z values. A possible reason for this abrupt transition could be related to the insufficient proton excitations in the g(9/2), d(5/2), and s(1/2) orbitals to generate strong quadrupole correlations or to the coexistence of competing different shapes. An unexpected continuous decrease of R-4/2 as a function of the neutron number up to N = 60 is also evidenced. This measurement establishes the Kr isotopic chain as the low-Z boundary of the island of deformation for N = 60 isotones. A comparison with available theoretical predictions using different beyond mean-field approaches shows that these models fail to reproduce the abrupt transitions at N = 60 and Z = 36.

Published
2017

16. Lifetime measurements in Pd-102: Searching for empirical proof of the E(5) critical-point symmetry in nuclear structure

Author

Konstantinopoulos, T., Ashley, S. F., Axiotis, M., Spyrou, A., Harissopulos, S., Dewald, A., Litzinger, J., Moeller, O., Mueller-Gatterman, C., Petkov, P., Napoli, D. R., Marginean, N., de Angelis, G., Ur, C. A., Bazzacco, D., Farnea, E., Lenzi, S. M., Vlastou, R., Balabanski, D., Konstantinopoulos, T., Ashley, S. F., Axiotis, M., Spyrou, A., Harissopulos, S., Dewald, A., Litzinger, J., Moeller, O., Mueller-Gatterman, C., Petkov, P., Napoli, D. R., Marginean, N., de Angelis, G., Ur, C. A., Bazzacco, D., Farnea, E., Lenzi, S. M., Vlastou, R., and Balabanski, D.

Abstract

Lifetimes of yrast and nonyrast states of Pd-102 populated via the Zr-92(C-13, 3n) reaction are measured by means of the recoil distance Doppler-shift technique with a Cologne plunger coupled to a GASP spectrometer. The event-by-event data accumulated at 24 plunger distances in the range of 0.1 mu m to 9 mm are analyzed using the differential decay curve method. The resulting B(E2) values of the gamma transitions depopulating yrast-band members up to the I-pi = 8(+) state are found to deviate significantly from the corresponding predictions of the E(5) critical-point symmetry.

Published
2016

17. Lifetime measurements in Pd-102: Searching for empirical proof of the E(5) critical-point symmetry in nuclear structure

Author

Konstantinopoulos, T., Ashley, S. F., Axiotis, M., Spyrou, A., Harissopulos, S., Dewald, A., Litzinger, J., Moeller, O., Mueller-Gatterman, C., Petkov, P., Napoli, D. R., Marginean, N., de Angelis, G., Ur, C. A., Bazzacco, D., Farnea, E., Lenzi, S. M., Vlastou, R., Balabanski, D., Konstantinopoulos, T., Ashley, S. F., Axiotis, M., Spyrou, A., Harissopulos, S., Dewald, A., Litzinger, J., Moeller, O., Mueller-Gatterman, C., Petkov, P., Napoli, D. R., Marginean, N., de Angelis, G., Ur, C. A., Bazzacco, D., Farnea, E., Lenzi, S. M., Vlastou, R., and Balabanski, D.

Abstract

Lifetimes of yrast and nonyrast states of Pd-102 populated via the Zr-92(C-13, 3n) reaction are measured by means of the recoil distance Doppler-shift technique with a Cologne plunger coupled to a GASP spectrometer. The event-by-event data accumulated at 24 plunger distances in the range of 0.1 mu m to 9 mm are analyzed using the differential decay curve method. The resulting B(E2) values of the gamma transitions depopulating yrast-band members up to the I-pi = 8(+) state are found to deviate significantly from the corresponding predictions of the E(5) critical-point symmetry.

Published
2016

18. High-spin spectroscopy of Ce-139

Author

Kaim, S., Petrache, C. M., Gargano, A., Itaco, N., Zerrouki, T., Leguillon, R., Astier, A., Deloncle, I., Konstantinopoulos, T., Regis, J. M., Wilmsen, D., Melon, B., Nannini, A., Ducoin, C., Guinet, D., Bhattacharjee, T., Kaim, S., Petrache, C. M., Gargano, A., Itaco, N., Zerrouki, T., Leguillon, R., Astier, A., Deloncle, I., Konstantinopoulos, T., Regis, J. M., Wilmsen, D., Melon, B., Nannini, A., Ducoin, C., Guinet, D., and Bhattacharjee, T.

Abstract

High-spin states in Ce-139 have been populated using the Te-130(C-14,5n) reaction. The level scheme has been extended to higher spins, including a new band of dipole transitions. The parity of several states has been changed from negative to positive, mainly based on the comparison with the level structure of the core nucleus Ce-140 and the results of a realistic shell-model calculation. The dipole band is interpreted as a magnetic rotation band with pi h(11/2)(2) circle times nu h(11/2)(-1) configuration built on small deformation axial shape with (epsilon(2) = 0.12, gamma = 0 degrees).

Published
2015

19. High-spin spectroscopy of Ce-139

Author

Kaim, S., Petrache, C. M., Gargano, A., Itaco, N., Zerrouki, T., Leguillon, R., Astier, A., Deloncle, I., Konstantinopoulos, T., Regis, J. M., Wilmsen, D., Melon, B., Nannini, A., Ducoin, C., Guinet, D., Bhattacharjee, T., Kaim, S., Petrache, C. M., Gargano, A., Itaco, N., Zerrouki, T., Leguillon, R., Astier, A., Deloncle, I., Konstantinopoulos, T., Regis, J. M., Wilmsen, D., Melon, B., Nannini, A., Ducoin, C., Guinet, D., and Bhattacharjee, T.

Abstract

High-spin states in Ce-139 have been populated using the Te-130(C-14,5n) reaction. The level scheme has been extended to higher spins, including a new band of dipole transitions. The parity of several states has been changed from negative to positive, mainly based on the comparison with the level structure of the core nucleus Ce-140 and the results of a realistic shell-model calculation. The dipole band is interpreted as a magnetic rotation band with pi h(11/2)(2) circle times nu h(11/2)(-1) configuration built on small deformation axial shape with (epsilon(2) = 0.12, gamma = 0 degrees).

Published
2015

20. High-spin spectroscopy of Ce-139

Author

Kaim, S., Petrache, C. M., Gargano, A., Itaco, N., Zerrouki, T., Leguillon, R., Astier, A., Deloncle, I., Konstantinopoulos, T., Regis, J. M., Wilmsen, D., Melon, B., Nannini, A., Ducoin, C., Guinet, D., Bhattacharjee, T., Kaim, S., Petrache, C. M., Gargano, A., Itaco, N., Zerrouki, T., Leguillon, R., Astier, A., Deloncle, I., Konstantinopoulos, T., Regis, J. M., Wilmsen, D., Melon, B., Nannini, A., Ducoin, C., Guinet, D., and Bhattacharjee, T.

Abstract

High-spin states in Ce-139 have been populated using the Te-130(C-14,5n) reaction. The level scheme has been extended to higher spins, including a new band of dipole transitions. The parity of several states has been changed from negative to positive, mainly based on the comparison with the level structure of the core nucleus Ce-140 and the results of a realistic shell-model calculation. The dipole band is interpreted as a magnetic rotation band with pi h(11/2)(2) circle times nu h(11/2)(-1) configuration built on small deformation axial shape with (epsilon(2) = 0.12, gamma = 0 degrees).

Published
2015

21. High-spin spectroscopy of Ce-139

Author

Kaim, S., Petrache, C. M., Gargano, A., Itaco, N., Zerrouki, T., Leguillon, R., Astier, A., Deloncle, I., Konstantinopoulos, T., Regis, J. M., Wilmsen, D., Melon, B., Nannini, A., Ducoin, C., Guinet, D., Bhattacharjee, T., Kaim, S., Petrache, C. M., Gargano, A., Itaco, N., Zerrouki, T., Leguillon, R., Astier, A., Deloncle, I., Konstantinopoulos, T., Regis, J. M., Wilmsen, D., Melon, B., Nannini, A., Ducoin, C., Guinet, D., and Bhattacharjee, T.

Abstract

High-spin states in Ce-139 have been populated using the Te-130(C-14,5n) reaction. The level scheme has been extended to higher spins, including a new band of dipole transitions. The parity of several states has been changed from negative to positive, mainly based on the comparison with the level structure of the core nucleus Ce-140 and the results of a realistic shell-model calculation. The dipole band is interpreted as a magnetic rotation band with pi h(11/2)(2) circle times nu h(11/2)(-1) configuration built on small deformation axial shape with (epsilon(2) = 0.12, gamma = 0 degrees).

Published
2015

22. Investigation of the reaction Ge-74(p,gamma)As-75 using the in-beam method to improve reaction network predictions for p nuclei

Author

Sauerwein, A., Endres, J., Netterdon, L., Zilges, A., Foteinou, V., Provatas, G., Konstantinopoulos, T., Axiotis, M., Ashley, S. F., Harissopulos, S., Rauscher, T., Sauerwein, A., Endres, J., Netterdon, L., Zilges, A., Foteinou, V., Provatas, G., Konstantinopoulos, T., Axiotis, M., Ashley, S. F., Harissopulos, S., and Rauscher, T.

Abstract

Background: Astrophysical models studying the origin of the neutron-deficient p nuclides require knowledge of proton capture cross sections at low energy. The production site of the p nuclei is still under discussion but a firm basis of nuclear reaction rates is required to address the astrophysical uncertainties. Data at astrophysically relevant interaction energies are scarce. Problems with the prediction of charged particle capture cross sections at low energy were found in the comparisons between previous data and calculations in the Hauser-Feshbach statistical model of compound reactions. Purpose: A measurement of Ge-74(p,gamma)As-75 at low proton energies, inside the astrophysically relevant energy region, is important in several respects. The reaction is directly important because it is a bottleneck in the reaction flow which produces the lightest p nucleus Se-74. It is also an important addition to the data set required to test reaction-rate predictions and to allow an improvement in the global p + nucleus optical potential required in such calculations. Method: An in-beam experiment was performed, making it possible to measure in the range 2.1 <= E-p <= 3.7 MeV, which is for the most part inside the astrophysically relevant energy window. Angular distributions of the gamma-ray transitions were measured with high-purity germanium detectors at eight angles relative to the beam axis. In addition to the total cross sections, partial cross sections for the direct population of 12 levels were determined. Results: The resulting cross sections were compared to Hauser-Feshbach calculations using the code SMARAGD. Only a constant renormalization factor of the calculated proton widths allowed a good reproduction of both total and partial cross sections. The accuracy of the calculation made it possible to check the spin assignment of some states in As-75. In the case of the 1075-keV state, a double state with spins and parities of 3/2- and 5/2- is needed to explain the

Published
2012

23. Investigation of the reaction Ge-74(p,gamma)As-75 using the in-beam method to improve reaction network predictions for p nuclei

Author

Sauerwein, A., Endres, J., Netterdon, L., Zilges, A., Foteinou, V., Provatas, G., Konstantinopoulos, T., Axiotis, M., Ashley, S. F., Harissopulos, S., Rauscher, T., Sauerwein, A., Endres, J., Netterdon, L., Zilges, A., Foteinou, V., Provatas, G., Konstantinopoulos, T., Axiotis, M., Ashley, S. F., Harissopulos, S., and Rauscher, T.

Abstract

Background: Astrophysical models studying the origin of the neutron-deficient p nuclides require knowledge of proton capture cross sections at low energy. The production site of the p nuclei is still under discussion but a firm basis of nuclear reaction rates is required to address the astrophysical uncertainties. Data at astrophysically relevant interaction energies are scarce. Problems with the prediction of charged particle capture cross sections at low energy were found in the comparisons between previous data and calculations in the Hauser-Feshbach statistical model of compound reactions. Purpose: A measurement of Ge-74(p,gamma)As-75 at low proton energies, inside the astrophysically relevant energy region, is important in several respects. The reaction is directly important because it is a bottleneck in the reaction flow which produces the lightest p nucleus Se-74. It is also an important addition to the data set required to test reaction-rate predictions and to allow an improvement in the global p + nucleus optical potential required in such calculations. Method: An in-beam experiment was performed, making it possible to measure in the range 2.1 <= E-p <= 3.7 MeV, which is for the most part inside the astrophysically relevant energy window. Angular distributions of the gamma-ray transitions were measured with high-purity germanium detectors at eight angles relative to the beam axis. In addition to the total cross sections, partial cross sections for the direct population of 12 levels were determined. Results: The resulting cross sections were compared to Hauser-Feshbach calculations using the code SMARAGD. Only a constant renormalization factor of the calculated proton widths allowed a good reproduction of both total and partial cross sections. The accuracy of the calculation made it possible to check the spin assignment of some states in As-75. In the case of the 1075-keV state, a double state with spins and parities of 3/2- and 5/2- is needed to explain the

Published
2012

24. Coulomb excitation of Ga-73

Author

Diriken, J., Stefanescu, I., Balabanski, D., Blasi, N., Blazhev, A., Bree, N., Cederkaell, J., Cocolios, T. E., Davinson, T., Eberth, J., Ekstrom, A., Fedorov, D. V., Fedosseev, V. N., Fraile, L. M., Franchoo, S., Georgiev, G., Gladnishki, K., Huyse, M., Ivanov, O. V., Ivanov, V. S., Iwanicki, J., Jolie, J., Konstantinopoulos, T., Kroell, Th., Kruecken, R., Koester, U., Lagoyannis, A., Lo Bianco, G., Maierbeck, P., Marsh, B. A., Napiorkowski, P., Patronis, N., Pauwels, D., Reiter, P., Seliverstov, M., Sletten, G., Van de Walle, J., Van Duppen, P., Voulot, D., Walters, W. B., Warr, N., Wenander, F., Wrzosek, K., Diriken, J., Stefanescu, I., Balabanski, D., Blasi, N., Blazhev, A., Bree, N., Cederkaell, J., Cocolios, T. E., Davinson, T., Eberth, J., Ekstrom, A., Fedorov, D. V., Fedosseev, V. N., Fraile, L. M., Franchoo, S., Georgiev, G., Gladnishki, K., Huyse, M., Ivanov, O. V., Ivanov, V. S., Iwanicki, J., Jolie, J., Konstantinopoulos, T., Kroell, Th., Kruecken, R., Koester, U., Lagoyannis, A., Lo Bianco, G., Maierbeck, P., Marsh, B. A., Napiorkowski, P., Patronis, N., Pauwels, D., Reiter, P., Seliverstov, M., Sletten, G., Van de Walle, J., Van Duppen, P., Voulot, D., Walters, W. B., Warr, N., Wenander, F., and Wrzosek, K.

Abstract

The B(E2; I-i -> I-f) values for transitions in Ga-71(31)40 and Ga-73(31)42 were deduced from a Coulomb excitation experiment at the safe energy of 2.95 MeV/nucleon using post-accelerated beams of Ga-71,Ga-73 at the REX-ISOLDE on-line isotope mass separator facility. The emitted gamma rays were detected by the MINIBALL gamma-detector array, and B(E2; I-i -> I-f) values were obtained from the yields normalized to the known strength of the 2(+) -> 0(+) transition in the Sn-120 target. The comparison of these new results with the data of less neutron-rich gallium isotopes shows a shift of the E2 collectivity toward lower excitation energy when adding neutrons beyond N = 40. This supports conclusions from previous studies of the gallium isotopes, which indicated a structural change in this isotopic chain between N = 40 and 42. Combined with recent measurements from collinear laser spectroscopy showing a 1/2(-) spin and parity for the ground state, the extracted results revealed evidence for a 1/2(-), 3/2(-) doublet near the ground state in Ga-73(31)42 differing by at most 0.8 keV in energy.

Published
2010

25. Coulomb excitation of Ga-73

Author

Diriken, J., Stefanescu, I., Balabanski, D., Blasi, N., Blazhev, A., Bree, N., Cederkaell, J., Cocolios, T. E., Davinson, T., Eberth, J., Ekstrom, A., Fedorov, D. V., Fedosseev, V. N., Fraile, L. M., Franchoo, S., Georgiev, G., Gladnishki, K., Huyse, M., Ivanov, O. V., Ivanov, V. S., Iwanicki, J., Jolie, J., Konstantinopoulos, T., Kroell, Th., Kruecken, R., Koester, U., Lagoyannis, A., Lo Bianco, G., Maierbeck, P., Marsh, B. A., Napiorkowski, P., Patronis, N., Pauwels, D., Reiter, P., Seliverstov, M., Sletten, G., Van de Walle, J., Van Duppen, P., Voulot, D., Walters, W. B., Warr, N., Wenander, F., Wrzosek, K., Diriken, J., Stefanescu, I., Balabanski, D., Blasi, N., Blazhev, A., Bree, N., Cederkaell, J., Cocolios, T. E., Davinson, T., Eberth, J., Ekstrom, A., Fedorov, D. V., Fedosseev, V. N., Fraile, L. M., Franchoo, S., Georgiev, G., Gladnishki, K., Huyse, M., Ivanov, O. V., Ivanov, V. S., Iwanicki, J., Jolie, J., Konstantinopoulos, T., Kroell, Th., Kruecken, R., Koester, U., Lagoyannis, A., Lo Bianco, G., Maierbeck, P., Marsh, B. A., Napiorkowski, P., Patronis, N., Pauwels, D., Reiter, P., Seliverstov, M., Sletten, G., Van de Walle, J., Van Duppen, P., Voulot, D., Walters, W. B., Warr, N., Wenander, F., and Wrzosek, K.

Abstract

The B(E2; I-i -> I-f) values for transitions in Ga-71(31)40 and Ga-73(31)42 were deduced from a Coulomb excitation experiment at the safe energy of 2.95 MeV/nucleon using post-accelerated beams of Ga-71,Ga-73 at the REX-ISOLDE on-line isotope mass separator facility. The emitted gamma rays were detected by the MINIBALL gamma-detector array, and B(E2; I-i -> I-f) values were obtained from the yields normalized to the known strength of the 2(+) -> 0(+) transition in the Sn-120 target. The comparison of these new results with the data of less neutron-rich gallium isotopes shows a shift of the E2 collectivity toward lower excitation energy when adding neutrons beyond N = 40. This supports conclusions from previous studies of the gallium isotopes, which indicated a structural change in this isotopic chain between N = 40 and 42. Combined with recent measurements from collinear laser spectroscopy showing a 1/2(-) spin and parity for the ground state, the extracted results revealed evidence for a 1/2(-), 3/2(-) doublet near the ground state in Ga-73(31)42 differing by at most 0.8 keV in energy.

Published
2010

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