Search

Your search keyword '"T, Braunroth"' showing total 22 results
Start Over Author "T, Braunroth" Language english
22 results on '"T, Braunroth"'

1. Enhanced quadrupole collectivity in doubly-magic 56Ni: Lifetime measurements of the 41+ and 61+ states

Author

K. Arnswald, A. Blazhev, F. Nowacki, P. Petkov, P. Reiter, T. Braunroth, A. Dewald, M. Droste, C. Fransen, R. Hirsch, V. Karayonchev, L. Kaya, L. Lewandowski, C. Müller-Gatermann, M. Seidlitz, B. Siebeck, A. Vogt, D. Werner, and K.O. Zell

Subjects
Doubly-magic nuclei, N=Z nuclei, Lifetime measurements, DSAM, B(E2) values, Physics, QC1-999
Abstract

Lifetime measurements of excited states in doubly-magic 56Ni have been performed exploiting the Doppler-shift attenuation method in order to determine reduced transition probabilities. For the 41+ and 61+ states, the deduced B(E2) values are compared with results from shell-model calculations employing the GXPF1A and the modern PFSDG-U interactions. In addition, valence ab-initio calculations were performed using a novel realistic Hamiltonian derived from chiral perturbation theory including three-body potential contributions and are confronted with the experimental findings. The new results show maximum E2 strength in comparison with known values along the N=28 chain of isotones. The results corroborate the high collectivity for the double shell closure at N=Z=28 which was anticipated from the large B(E2;21+→0g.s.+) value despite the considerable increase of its excitation energy as compared to neighboring semi-magic nuclei. Based on similarities in the shell structures of the self-conjugate doubly-magic nuclei 56Ni and 100Sn, the new values could be an indication for an expected comparable collective behavior of the 61+ state in 100Sn.

Published
2021
Full Text
View/download PDF

2. Lifetime measurements of excited states in 169,171,173Os: Persistence of anomalous B(E2) ratios in transitional rare earth nuclei in the presence of a decoupled i13/2 valence neutron

Author

W. Zhang, B. Cederwall, M. Doncel, Ö. Aktas, A. Ertoprak, R. Liotta, C. Qi, T. Grahn, B.S. Nara Singh, D.M. Cullen, D. Hodge, M. Giles, S. Stolze, H. Badran, T. Braunroth, T. Calverley, D.M. Cox, Y.D. Fang, P.T. Greenlees, J. Hilton, E. Ideguchi, R. Julin, S. Juutinen, M. Kumar Raju, H. Li, H. Liu, S. Matta, P. Subramaniam, V. Modamio, J. Pakarinen, P. Papadakis, J. Partanen, C.M. Petrache, P. Rahkila, P. Ruotsalainen, M. Sandzelius, J. Sarén, C. Scholey, J. Sorri, M.J. Taylor, J. Uusitalo, and J.J. Valiente-Dobón

Subjects
Physics, QC1-999
Abstract

Lifetimes of low-lying excited states in the νi13/2+ bands of the neutron-deficient osmium isotopes 169,171,173Os have been measured for the first time using the recoil-distance Doppler shift and recoil-isomer tagging techniques. An unusually low value is observed for the ratio B(E2;21/2+→17/2+)/B(E2;17/2+→13/2+) in 169Os, similar to the “anomalously” low values of the ratio B(E2;41+→21+)/B(E2;21+→0gs+) previously observed in several transitional rare-earth nuclides with even numbers of neutrons and protons, including the neighbouring 168,170Os. Furthermore, the evolution of B(E2;21/2+→17/2+)/B(E2;17/2+→13/2+) with increasing neutron number in the odd-mass isotopic chain 169,171,173Os is observed to follow the same trend as observed previously in the even-even Os isotopes. These findings indicate that the possible quantum phase transition from a seniority conserving structure to a collective regime as a function of neutron number suggested for the even-even systems is maintained in these odd-mass osmium nuclei, with the odd valence neutron merely acting as a “spectator”. As for the even-even nuclei, the phenomenon is highly unexpected for nuclei that are not situated near closed shells.

Published
2021
Full Text
View/download PDF

3. Pairing-quadrupole interplay in the neutron-deficient tin nuclei: First lifetime measurements of low-lying states in 106,108Sn

Author

M. Siciliano, J.J. Valiente-Dobón, A. Goasduff, F. Nowacki, A.P. Zuker, D. Bazzacco, A. Lopez-Martens, E. Clément, G. Benzoni, T. Braunroth, F.C.L. Crespi, N. Cieplicka-Oryńczak, M. Doncel, S. Ertürk, G. de France, C. Fransen, A. Gadea, G. Georgiev, A. Goldkuhle, U. Jakobsson, G. Jaworski, P.R. John, I. Kuti, A. Lemasson, T. Marchi, D. Mengoni, C. Michelagnoli, T. Mijatović, C. Müller-Gatermann, D.R. Napoli, J. Nyberg, M. Palacz, R.M. Pérez-Vidal, B. Sayği, D. Sohler, S. Szilner, D. Testov, M. Zielińska, D. Barrientos, B. Birkenbach, H.C. Boston, A.J. Boston, B. Cederwall, J. Collado, D.M. Cullen, P. Désesquelles, C. Domingo-Pardo, J. Dudouet, J. Eberth, F.J. Egea-Canet, V. González, L.J. Harkness-Brennan, H. Hess, D.S. Judson, A. Jungclaus, W. Korten, M. Labiche, A. Lefevre, S. Leoni, H. Li, A. Maj, R. Menegazzo, B. Million, A. Pullia, F. Recchia, P. Reiter, M.D. Salsac, E. Sanchis, O. Stezowski, and Ch. Theisen

Subjects
Lifetime, Nuclear structure, Multi-nucleon transfer, Light Sn, Tracking array, Physics, QC1-999
Abstract

The lifetimes of the low-lying excited states 2+ and 4+ have been directly measured in the neutron-deficient 106,108Sn isotopes. The nuclei were populated via a deep-inelastic reaction and the lifetime measurement was performed employing a differential plunger device. The emitted γ rays were detected by the AGATA array, while the reaction products were uniquely identified by the VAMOS++ magnetic spectrometer. Large-Scale Shell-Model calculations with realistic forces indicate that, independently of the pairing content of the interaction, the quadrupole force is dominant in the B(E2;21+→0g.s.+) values and it describes well the experimental pattern for 104−114Sn; the B(E2;41+→21+) values, measured here for the first time, depend critically on a delicate pairing-quadrupole balance, disclosed by the very precise results in 108Sn.

Published
2020
Full Text
View/download PDF

4. Lifetime measurement of the 21+ state in 74Rb and isospin properties of quadrupole transition strengths at N = Z

Author

C. Morse, H. Iwasaki, A. Lemasson, A. Dewald, T. Braunroth, V.M. Bader, T. Baugher, D. Bazin, J.S. Berryman, C.M. Campbell, A. Gade, C. Langer, I.Y. Lee, C. Loelius, E. Lunderberg, F. Recchia, D. Smalley, S.R. Stroberg, R. Wadsworth, C. Walz, D. Weisshaar, A. Westerberg, K. Whitmore, and K. Wimmer

Subjects
Physics, QC1-999
Abstract

Self-conjugate nuclei in the A≈70–80 region have attracted a great deal of attention due to phenomena such as shape coexistence and increasing collectivity along the N=Z line. We investigate the structure of nuclei in this region through lifetime measurements using the GRETINA array. The first implementation of the Differential Recoil Distance Doppler Shift technique with fast radioactive beams is demonstrated and verified through a measurement of the well-known B(E2;21+→01+) transition strength in 74Kr. The method is then applied to determine the B(E2;21+→01+) transition strength in 74Rb, the heaviest odd–odd N=Z nucleus for which this quantity has been determined. This result and extended systematics along N=Z suggest the dominance of the isoscalar part of the quadrupole transition strengths in self-conjugate nuclei, as well as the possible presence of shape coexistence in 74Rb. Keywords: Lifetimes, Nuclear transition probabilities, Isospin

Published
2018
Full Text
View/download PDF

5. Enhanced collectivity along the N=Z line: Lifetime measurements in 44Ti, 48Cr, and 52Fe

Author

K. Arnswald, T. Braunroth, M. Seidlitz, L. Coraggio, P. Reiter, B. Birkenbach, A. Blazhev, A. Dewald, C. Fransen, B. Fu, A. Gargano, H. Hess, R. Hirsch, N. Itaco, S.M. Lenzi, L. Lewandowski, J. Litzinger, C. Müller-Gatermann, M. Queiser, D. Rosiak, D. Schneiders, B. Siebeck, T. Steinbach, A. Vogt, K. Wolf, and K.O. Zell

Subjects
N=Z nuclei, Lifetime measurements, RDDS, B(E2) values, Physics, QC1-999
Abstract

Lifetimes of the 21+ states in 44Ti, 48,50Cr, and 52Fe were determined with high accuracy exploiting the recoil distance Doppler-shift method. The reduced E2 transition strengths of 44Ti and 52Fe differ considerably from previously known values. A systematic increase in collectivity is found for the N=Z nuclei compared to neighboring isotopes. The B(E2) values along the Ti, Cr, and Fe isotopic chains are compared to shell-model calculations employing established interactions for the 0f1p shell, as well as a novel effective shell-model Hamiltonian starting from a realistic nucleon–nucleon potential. The theoretical approaches underestimate the B(E2) values for the lower-mass Ti isotopes. Strong indication is found for particle-hole cross-shell configurations, recently corroborated by similar results for the neighboring isotone 42Ca.

Published
2017
Full Text
View/download PDF

6. Lifetime measurements of excited states in 163W and the implications for the anomalous B(E2) ratios in transitional nuclei

Author

M.C. Lewis, D.T. Joss, B. Sayğı, R.D. Page, D.M. Cullen, L. Barber, M.M. Giles, J. Simpson, M.A.M. Al-Aqeel, H. Badran, T. Braunroth, A.D. Briscoe, T. Calverley, A. Dewald, M. Doncel, T. Grahn, P.T. Greenlees, C. Henrich, A. Herzáň, R.-D. Herzberg, E. Higgins, J. Hilton, S. Ilieva, R. Julin, S. Juutinen, J. Keatings, T. Kröll, M. Labiche, K. Mashtakov, B.S. Nara Singh, E. Parr, J. Partanen, E.S. Paul, P. Rahkila, M. Sandzelius, J. Sarén, C. Scholey, M. Siciliano, P. Spagnoletti, S. Stolze, S.V. Szwec, M.J. Taylor, and J. Uusitalo

Subjects
Physics, QC1-999
Abstract

This letter reports lifetime measurements of excited states in the odd-N nucleus 163W using the recoil-distance Doppler shift method to probe the core polarising effect of the i13/2 neutron orbital on the underlying soft triaxial even-even core. The ratio B(E2:21/2+→17/2+)/B(E2:17/2+→13/2+) is consistent with the predictions of the collective rotational model. The deduced B(E2) values provide insights into the validity of collective model predictions for heavy transitional nuclei and a geometric origin for the anomalous B(E2) ratios observed in nearby even-even nuclei is proposed. Keywords: Mean lifetimes, B(E2) reduced transition probabilities, Recoil-distance Doppler-shift method, Nuclear deformation, Gamma-ray Spectroscopy

Published
2019
Full Text
View/download PDF

7. Evidence of Partial Seniority Conservation in the πg_{9/2} Shell for the N=50 Isotones

Author

R M, Pérez-Vidal, A, Gadea, C, Domingo-Pardo, A, Gargano, J J, Valiente-Dobón, E, Clément, A, Lemasson, L, Coraggio, M, Siciliano, S, Szilner, M, Bast, T, Braunroth, J, Collado, A, Corina, A, Dewald, M, Doncel, J, Dudouet, G, de France, C, Fransen, V, González, T, Hüyük, B, Jacquot, P R, John, A, Jungclaus, Y H, Kim, A, Korichi, M, Labiche, S, Lenzi, H, Li, J, Ljungvall, A, López-Martens, D, Mengoni, C, Michelagnoli, C, Müller-Gatermann, D R, Napoli, A, Navin, B, Quintana, D, Ramos, M, Rejmund, E, Sanchis, J, Simpson, O, Stezowski, D, Wilmsen, M, Zielińska, A J, Boston, D, Barrientos, P, Bednarczyk, G, Benzoni, B, Birkenbach, H C, Boston, A, Bracco, B, Cederwall, D M, Cullen, F, Didierjean, J, Eberth, A, Gottardo, J, Goupil, L J, Harkness-Brennan, H, Hess, D S, Judson, A, Kaşkaş, W, Korten, S, Leoni, R, Menegazzo, B, Million, J, Nyberg, Zs, Podolyak, A, Pullia, D, Ralet, F, Recchia, P, Reiter, K, Rezynkina, M D, Salsac, M, Şenyiğit, D, Sohler, Ch, Theisen, D, Verney, Ministerio de Ciencia e Innovación (España), Generalitat Valenciana, European Commission, Department of Energy (US), Croatian Science Foundation, and Pérez-Vidal, R.M.

Abstract

7 pags., 3 figs., 1 tab., The reduced transition probabilities for the 4_{1}^{+}→2_{1}^{+} and 2_{1}^{+}→0_{1}^{+} transitions in ^{92}Mo and ^{94}Ru and for the 4_{1}^{+}→2_{1}^{+} and 6_{1}^{+}→4_{1}^{+} transitions in ^{90}Zr have been determined in this experiment making use of a multinucleon transfer reaction. These results have been interpreted on the basis of realistic shell-model calculations in the f_{5/2}, p_{3/2}, p_{1/2}, and g_{9/2} proton valence space. Only the combination of extensive lifetime information and large scale shell-model calculations allowed the extent of the seniority conservation in the N=50 g_{9/2} orbital to be understood. The conclusion is that seniority is largely conserved in the first πg_{9/2} orbital., This work was partially supported by MCIN/AEI/10.13039/501100011033 and Generalitat Valenciana, Spain, under Grants No. FPA2017-84756-C4, No. PID2020–118265GB-C4, and No. PROMETEO 2019/005, by the EU FEDER funds, by the European Union’s Horizon 2020 research and innovation program under Grant Agreement No. n654002, by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357, by STFC(UK) and by the Croatian Science Foundation under Projects No. 7194 and No. IP-2018-01-1257.

Published
2022

8. Complete set of bound negative-parity states in the neutron-rich nucleus 18N

Author

S. Ziliani, M. Ciemała, F. C. L. Crespi, S. Leoni, B. Fornal, T. Suzuki, T. Otsuka, A. Maj, P. Bednarczyk, G. Benzoni, A. Bracco, C. Boiano, S. Bottoni, S. Brambilla, M. Bast, M. Beckers, T. Braunroth, F. Camera, N. Cieplicka-Oryńczak, E. Clément, S. Coelli, O. Dorvaux, S. Erturk, G. de France, C. Fransen, A. Goldkuhle, J. Grębosz, M. N. Harakeh, Ł. W. Iskra, B. Jacquot, A. Karpov, M. Kicińska-Habior, Y. Kim, M. Kmiecik, A. Lemasson, S. M. Lenzi, M. Lewitowicz, H. Li, I. Matea, K. Mazurek, C. Michelagnoli, M. Matejska-Minda, B. Million, C. Müller-Gatermann, V. Nanal, P. Napiorkowski, D. R. Napoli, R. Palit, M. Rejmund, Ch. Schmitt, M. Stanoiu, I. Stefan, E. Vardaci, B. Wasilewska, O. Wieland, M. Ziębliński, M. Zielińska, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
Set (abstract data type), Physics, Particle physics, medicine.anatomical_structure, 010308 nuclear & particles physics, 0103 physical sciences, medicine, Neutron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, Parity (mathematics), 01 natural sciences, Nucleus
Abstract

International audience; High-resolution γ-ray spectroscopy of N18 is performed with the Advanced GAmma Tracking Array, following deep-inelastic processes induced by an O18 beam on a Ta181 target. Six states are newly identified, which together with the three known excitations exhaust all negative-parity excited states expected in N18 below the neutron threshold. Spin and parities are proposed for all located states on the basis of decay branchings and comparison with large-scale shell-model calculations performed in the p-sd space, with the YSOX interaction. Of particular interest is the location of the 01− and 12− excitations, which provide strong constrains for cross-shell p-sd matrix elements based on realistic interactions and help to simultaneously reproduce the ground and first-excited states in N16 and N18, for the first time. Understanding the N18 structure may also have significant impact on neutron-capture cross-section calculations in r-process modeling including light neutron-rich nuclei.

Published
2021
Full Text
View/download PDF

9. Spectroscopy of neutron-rich nitrogen isotopes with Agata+Paris+Vamos

Author

S. Ziliani, M. Ciemała, F.C.L. Crespi, S. Leoni, B. Fornal, A. Maj, P. Bednarczyk, G. Benzoni, A. Bracco, C. Boiano, S. Bottoni, S. Brambilla, M. Bast, M. Beckers, T. Braunroth, F. Camera, N. Cieplicka-Oryńczak, E. Clément, S. Coelli, O. Dorvaux, S. Erturk, G. de France, C. Fransen, A. Goldkuhle, J. Grębosz, M.N. Harakeh, Ł.W. Iskra, B. Jacquot, A. Karpov, M. Kicińska-Habior, Y. Kim, M. Kmiecik, A. Lemasson, S.M. Lenzi, M. Lewitowicz, H. Li, I. Matea, K. Mazurek, C. Michelagnoli, M. Matejska-Minda, B. Million, C. Müller-Gatermann, V. Nanal, P. Napiorkowski, D.R. Napoli, R. Palit, M. Rejmund, Ch. Schmitt, M. Stanoiu, I. Stefan, E. Vardaci, B. Wasilewska, O. Wieland, M. Ziębliński, M. Zielińska, Ziliani, S., Ciemała, M., Crespi, F. C. L., Leoni, S., Fornal, B., Maj, A., Bednarczyk, P., Benzoni, G., Bracco, A., Boiano, C., Bottoni, S., Brambilla, S., Bast, M., Beckers, M., Braunroth, T., Camera, F., Cieplicka-Orynczak, N., Clément, E., Coelli, S., Dorvaux, O., Erturk, S., de France, G., Fransen, C., Goldkuhle, A., Grebosz, J., Harakeh, M. N., Iskra, Ł. W., Jacquot, B., Karpov, A., Kicinska-Habior, M., Kim, Y., Kmiecik, M., Lemasson, A., Lenzi, S. M., Lewitowicz, M., Li, H., Matea, I., Mazurek, K., Michelagnoli, C., Matejska-Minda, M., Million, B., Müller-Gatermann, C., Nanal, V., Napiorkowski, P., Napoli, D. R., Palit, R., Rejmund, M., Schmitt, Ch., Stanoiu, M., Stefan, I., Vardaci, E., Wasilewska, B., Wieland, O., Zieblinski, M., Zielinska, M., Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), ILL, and Research unit Nuclear & Hadron Physics

Subjects
Physics, education.field_of_study, Spectrometer, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Population, Gamma ray, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Excited state, 0103 physical sciences, Neutron, AGATA, 010306 general physics, Spectroscopy, education, Beam (structure)
Abstract

Excited states of 17N, 18N and 19N were investigated through the measurement of gamma rays, following their population via deep-inelastic reactions induced by an 18O beam (7 MeV/u) on a thick 181Ta target. The experimental setup comprised the AGATA+PARIS detection system, coupled to the VAMOS++ magnetic spectrometer. In the 17N nucleus, the analysis of gamma-ray transitions de-exciting two states around 4-5 MeV clearly pointed to discrepancies with the lifetime values reported in literature. Three new gamma rays were observed in 18N at the energies of 1662.3 (3) keV, 2073.4 (8) keV and 2300.9 (8) keV, and hints for other two new transitions around 1566 keV and 1720 keV were found. In addition, a new transition with energy of 2489.7 (8) keV was observed in 19N.

Published
2020
Full Text
View/download PDF

10. Lifetime Measurements of Low-lying States in $^{73}$Ga and $^{70,72,74}$Zn Isotopes

Author

T. Milanović, I. Čeliković, C. Michelagnoli, G. de France, A. Boso, T. Braunroth, E. Clément, A. Dewald, G. Georgiev, E. Ideguchi, B. Jacquot, W. Królas, D. Napoli, N. Lalović, K.Y. Lee, A. Lemasson, H. Li, J. Ljungvall, A. Navin, A. Nori, R. Perez-Vidal, M. Rejmund, P. Ujić, D. Wilmsen, Y. Yamamoto, M. Zielińska, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and ILL

Subjects
Physics, symbols.namesake, Recoil, Isotope, Spectrometer, symbols, General Physics and Astronomy, AGATA, Atomic physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Tracking (particle physics), Doppler effect, Beam (structure)
Abstract

International audience; Lifetimes of low-lying states in 73Ga and 70,72,74Zn were measured using the Recoil Distance Doppler Shift (RDDS) method. These nuclei were produced in deep-inelastic reactions in inverse kinematics with a 208Pb beam impinging on a 76Ge target. Prompt γ rays were detected using the AGATA tracking array coupled to the VAMOS++ spectrometer. Lifetime of the 5/2 − state in 73Ga, measured for the first time, provides additional evidence for the existence of a 1/2 −, 3/2 − ground-state doublet. The lifetimes of the 4 + states in 70,72,74Zn were remeasured in an attempt to understand the discrepancies observed between earlier measurements. Our results are in agreement with those of previous plunger experiments.

Published
2019
Full Text
View/download PDF

11. SPECTROSCOPY OF NEUTRON-RICH C, O, N AND F ISOTOPES WITH THE AGATA plus PARIS plus VAMOS SETUP AT GANIL

Author

S. Ziliani, M. Ciemała, F. Crespi, S. Leoni, B. Fornal, A. Maj, P. Bednarczyk, G. Benzoni, A. Bracco, C. Boiano, S. Bottoni, S. Brambilla, M. Bast, M. Beckers, T. Braunroth, F. Camera, N. Cieplicka-Oryńczak, E. Clément, O. Dorvaux, S. Erturk, G. De France, A. Goldkuhle, J. Grębosz, M.N. Harakeh, Ł.W. Iskra, B. Jacquot, M. Kicińska-Habior, Y. Kim, M. Kmiecik, A. Lemasson, H. Li, I. Matea, K. Mazurek, C. Michelagnoli, B. Million, C. Müller-Gatermann, P. Napiorkowski, V. Nanal, M. Matejska-Minda, M. Rejmund, Ch. Schmitt, M. Stanoiu, I. Stefan, B. Wasilewska, M. Ziębliński, Fornal, Bogdan -- 0000-0002-1142-8067, Ciemala, Michal -- 0000-0001-5328-720X, [Ziliani, S. -- Crespi, F. -- Leoni, S. -- Bracco, A. -- Bottoni, S. -- Camera, F.] Univ Milan, Milan, Italy -- [Ziliani, S. -- Crespi, F. -- Leoni, S. -- Benzoni, G. -- Bracco, A. -- Boiano, C. -- Bottoni, S. -- Brambilla, S. -- Camera, F. -- Million, B.] INFN, Sez Milano, Milan, Italy -- [Ciemala, M. -- Fornal, B. -- Maj, A. -- Bednarczyk, P. -- Cieplicka-Orynczak, N. -- Grebosz, J. -- Iskra, L. W. -- Kmiecik, M. -- Mazurek, K. -- Wasilewska, B.] Polish Acad Sci, Inst Nucl Phys, Krakow, Poland -- [Bast, M. -- Beckers, M. -- Braunroth, T. -- Goldkuhle, A. -- Mueller-Gatermann, C.] IKP Cologne, Cologne, Germany -- [Clement, E. -- De France, G. -- Jacquot, B. -- Kim, Y. -- Lemasson, A. -- Li, H. -- Rejmund, M.] CEA, DSAM, GANIL, Caen, France -- [Clement, E. -- De France, G. -- Jacquot, B. -- Kim, Y. -- Lemasson, A. -- Li, H. -- Rejmund, M.] CNRS, IN2P3, Caen, France -- [Dorvaux, O. -- Schmitt, Ch] CNRS, IN2P3, IPHC UMR 7178, Strasbourg, France -- [Erturk, S.] Nigde Univ, Nigde, Turkey -- [Harakeh, M. N.] KVI Ctr Adv Radiat Technol, Groningen, Netherlands -- [Kicinska-Habior, M. -- Matea, I -- Stefan, I] Warsaw Univ, Fac Phys, Warsaw, Poland -- [Kicinska-Habior, M. -- Matea, I -- Stefan, I] IPN, Orsay Lab, Orsay, France -- [Michelagnoli, C.] ILL Grenoble, Grenoble, France -- [Napiorkowski, P. -- Matejska-Minda, M.] Univ Warsaw, Heavy Ion Lab, Warsaw, Poland -- [Nanal, V] Dept Nucl & Atom Phys, Mumbai, Maharashtra, India -- [Stanoiu, M.] IFIN HH, Bucharest, Romania -- [Zieblinski, M.] CEA, DRF, IRFU, Ctr CEA Saclay, Saclay, France, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut Laue-Langevin (ILL), ILL, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 0-Belirlenecek, and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Isotope, Spectrometer, 010308 nuclear & particles physics, General Physics and Astronomy, Context (language use), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, 0-Belirlenecek, Nuclear physics, Nuclear interaction, Ab initio quantum chemistry methods, 0103 physical sciences, Neutron, AGATA, Spectroscopy, Nuclear Experiment
Abstract

Zakopane Conference on Nuclear Physics - Extremes of the Nuclear Landscape -- AUG 26-SEP 02, 2018 -- Zakopane, POLAND, WOS: 000463866500052, Recent ab initio calculations pointed out the importance of the three-body terms of the nuclear interaction, in the description of the structure of n-rich systems. The state lifetimes in light n-rich carbon and oxygen nuclei have been predicted to be sensitive to the three-body terms and, in this context, an experiment, aiming at the measurement of these lifetimes, was performed in GANIL in July 2017 with the AGATA and PARIS arrays coupled to the VAMOS++ magnetic spectrometer. Details on the AGATA preliminary data analysis are presented., National Science Centre, Poland (NCN) [2013/08/M/ST2/00257, 2014/14/M/ST2/00738, 2016/22/M/ST2/00269], This work was supported by the National Science Centre, Poland (NCN) under contracts No. 2013/08/M/ST2/00257, 2014/14/M/ST2/00738 and 2016/22/M/ST2/00269.

Published
2019
Full Text
View/download PDF

12. Determination of Lifetimes of Excited States in Neutron-rich $^{20}$O Isotope from Experiment with the AGATA+PARIS+VAMOS Setup

Author

M. Ciemała, S. Ziliani, F. Crespi, S. Leoni, B. Fornal, A. Maj, P. Bednarczyk, G. Benzoni, A. Bracco, C. Boiano, S. Bottoni, S. Brambilla, M. Bast, M. Beckers, T. Braunroth, F. Camera, N. Cieplicka-Oryńczak, E. Clément, O. Dorvaux, S. Ertürk, G. De France, A. Goldkuhle, J. Grębosz, M.N. Harakeh, Ł.W. Iskra, B. Jacquot, A. Karpov, M. Kicińska-Habior, Y. Kim, M. Kmiecik, A. Lemasson, H. Li, I. Matea, K. Mazurek, C. Michelagnoli, B. Millon, C. Müller-Gatermann, P. Napiorkowski, V. Nanal, M. Matejska-Minda, M. Rejmund, B. Sowicki, Ch. Schmitt, M. Stanoiu, I. Stefan, B. Wasilewska, M. Zielińska, M. Ziębliński, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut Laue-Langevin (ILL), ILL, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Nuclear Theory, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, Excited state, 0103 physical sciences, AGATA, Neutron, Nuclear Experiment
Abstract

International audience; An experiment aiming at measuring lifetimes of the second 2+ excited states in neutron-rich C and O isotopes was recently performed at the GANIL laboratory, in France. In these nuclei, recent ab initio calculations provide a detailed description of the nuclear excited states, predicting a strong sensitivity of the electromagnetic transition probabilities to the details of the nucleon–nucleon interactions, especially in connection with the role played by the three-body (NNN) forces. Thus, the measurement of 2 + states lifetimes in this region will be a stringent test of the importance of including the NNN forces in describing the electromagnetic properties of selected nuclear states. This contribution reports on the status of the experimental analysis for the case of lifetimes in 20O.

Published
2018
Full Text
View/download PDF

13. Study of Quadrupole Correlations in N = Z = 50 Region via Lifetime Measurements

Author

M. Siciliano, J.J. Valiente-Dobón, A. Goasduff, D. Bazzacco, N. Alahari, G. Benzoni, T. Braunroth, N. Cieplicka, F.C.L. Crespi, E. Clement, G. De France, M. Doncel, S. Ertürk, C. Fransen, A. Gadea, G. Georgiev, A. Goldkuhle, U. Jakobsson, G. Jaworski, P.R. John, I. Kuti, A. Lemasson, A. Lopez-Martens, H. Li, S. Lunardi, T. Marchi, D. Mengoni, C. Michelagnoli, T. Mijatovic, C. Müller-Gatermann, D.R. Napoli, J. Nyberg, M. Palacz, R.M. Pérez-Vidal, M. Rejmund, B. Saygi, D. Sohler, S. Szilner, D. Testov, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 010308 nuclear & particles physics, multinucleon transfer reactions, magnetic spectrometers, heavy nuclei, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Measure (physics), General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Excited state, 0103 physical sciences, Quadrupole, Order (group theory), AGATA, 010306 general physics, Nuclear Experiment
Abstract

During the AGATA campaign at GANIL, the neutron-deficient Sn region was populated via a multi-nucleon transfer reaction in order to directly measure the lifetime of the first excited states with a plunger device, providing complementary information to previous results obtained with Coulomb excitation experiments. The AGATA γ-ray array was used together with the VAMOS++ spectrometer to study the nuclei of interest. ispartof: Acta Physica Polonica B vol:48 issue:3 pages:331-336 ispartof: location:Zakopane: POLAND status: published

Published
2016
Full Text
View/download PDF

14. Lifetime measurments of excited states in neutron-rich fission fragments

Author

T.W. Hagen, L. Grente, A. Görgen, M.-D. Salsac, W. Korten, F. Farget, T. Braunroth, B. Bruyneel, I. Celikovic, E. Clément, G. de France, O. Delaune, A. Dewald, A. Dijon, M. Hackstein, B. Jacquot, J. Litzinger, J. Ljungvall, C. Louchart, C. Michelagnoli, D.R. Napoli, A. Navin, F. Recchia, M. Rejmund, W. Rother, E. Sahin, S. Siem, B. Sulignano, Ch. Theisen, J.J. Valiente-Dobon, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), CSNSM SNO, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM)

Subjects
Physics, Spectrometer, 010308 nuclear & particles physics, Fission, Gamma ray, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, symbols.namesake, Physics and Astronomy (all), Recoil, Excited state, 0103 physical sciences, symbols, Neutron, Atomic number, Atomic physics, Nuclear Experiment, Doppler effect
Abstract

Expérience GANIL/VAMOS/EXOGAM; International audience; Lifetimes of short-lived excited states in a wide range of neutron-richfission fragments were measured using the recoil distance Doppler shift(RDDS) technique, which was applied to fusion-fission reactions in inversekinematics for the first time. The fission fragments were identified eventby-event in mass, charge, and atomic number using the VAMOS magneticspectrometer at GANIL. Gamma rays originating from the fission fragmentswere measured with the EXOGAM array of Ge Clover detectors aroundthe target position. Using a degrader, the change in the Doppler shiftof the $\gamma$ ray allows the application of the RDDS method. Details of theexperimental technique will be discussed and the status for the ongoinganalysis for odd-mass yttrium isotopes will be presented.

Published
2015
Full Text
View/download PDF

16. Evidence of Partial Seniority Conservation in the πg_{9/2} Shell for the N=50 Isotones.

Author

Pérez-Vidal RM, Gadea A, Domingo-Pardo C, Gargano A, Valiente-Dobón JJ, Clément E, Lemasson A, Coraggio L, Siciliano M, Szilner S, Bast M, Braunroth T, Collado J, Corina A, Dewald A, Doncel M, Dudouet J, de France G, Fransen C, González V, Hüyük T, Jacquot B, John PR, Jungclaus A, Kim YH, Korichi A, Labiche M, Lenzi S, Li H, Ljungvall J, López-Martens A, Mengoni D, Michelagnoli C, Müller-Gatermann C, Napoli DR, Navin A, Quintana B, Ramos D, Rejmund M, Sanchis E, Simpson J, Stezowski O, Wilmsen D, Zielińska M, Boston AJ, Barrientos D, Bednarczyk P, Benzoni G, Birkenbach B, Boston HC, Bracco A, Cederwall B, Cullen DM, Didierjean F, Eberth J, Gottardo A, Goupil J, Harkness-Brennan LJ, Hess H, Judson DS, Kaşkaş A, Korten W, Leoni S, Menegazzo R, Million B, Nyberg J, Podolyak Z, Pullia A, Ralet D, Recchia F, Reiter P, Rezynkina K, Salsac MD, Şenyiğit M, Sohler D, Theisen C, and Verney D

Abstract

The reduced transition probabilities for the 4_{1}^{+}→2_{1}^{+} and 2_{1}^{+}→0_{1}^{+} transitions in ^{92}Mo and ^{94}Ru and for the 4_{1}^{+}→2_{1}^{+} and 6_{1}^{+}→4_{1}^{+} transitions in ^{90}Zr have been determined in this experiment making use of a multinucleon transfer reaction. These results have been interpreted on the basis of realistic shell-model calculations in the f_{5/2}, p_{3/2}, p_{1/2}, and g_{9/2} proton valence space. Only the combination of extensive lifetime information and large scale shell-model calculations allowed the extent of the seniority conservation in the N=50 g_{9/2} orbital to be understood. The conclusion is that seniority is largely conserved in the first πg_{9/2} orbital.

Published
2022
Full Text
View/download PDF

17. Stopping power of water for carbon ions with energies in the Bragg peak region.

Author

Baek WY, Braunroth T, de La Fuente Rosales L, Rahm JM, and Rabus H

Abstract

The stopping power of liquid water was measured for carbon ions with energies in the Bragg peak region using the inverted Doppler shift attenuation method. Among the semiempirical data, the results of this work agree best with the data recommended in the Errata and Addendum of ICRU Report No. 73, which is based on an I value of 78 eV for water. The agreement was worse when the present results were compared to the newer recommendation of the ICRU published in ICRU Report No. 90. The srim code seems to slightly overestimate the stopping power of water for carbon ions above 3 MeV. A semiexperimental stopping power of water for α particles was derived from the present results using the theoretical ratio between the stopping powers of water for carbon ions and α particles computed by means of the casp code. These values agree well with the experimental data for α particles within the uncertainties.

Published
2020
Full Text
View/download PDF

18. Publisher's Note: Direct Lifetime Measurements of the Excited States in ^{72}Ni [Phys. Rev. Lett. 116, 122502 (2016)].

Author

Kolos K, Miller D, Grzywacz R, Iwasaki H, Al-Shudifat M, Bazin D, Bingham CR, Braunroth T, Cerizza G, Gade A, Lemasson A, Liddick SN, Madurga M, Morse C, Portillo M, Rajabali MM, Recchia F, Riedinger LL, Voss P, Walters WB, Weisshaar D, Whitmore K, Wimmer K, and Tostevin JA

Abstract

This corrects the article DOI: 10.1103/PhysRevLett.116.122502.

Published
2020
Full Text
View/download PDF

19. Evidence for Coexisting Shapes through Lifetime Measurements in ^{98}Zr.

Author

Singh P, Korten W, Hagen TW, Görgen A, Grente L, Salsac MD, Farget F, Clément E, de France G, Braunroth T, Bruyneel B, Celikovic I, Delaune O, Dewald A, Dijon A, Delaroche JP, Girod M, Hackstein M, Jacquot B, Libert J, Litzinger J, Ljungvall J, Louchart C, Gottardo A, Michelagnoli C, Müller-Gatermann C, Napoli DR, Otsuka T, Pillet N, Recchia F, Rother W, Sahin E, Siem S, Sulignano B, Togashi T, Tsunoda Y, Theisen C, and Valiente-Dobon JJ

Abstract

The lifetimes of the first excited 2^{+}, 4^{+}, and 6^{+} states in ^{98}Zr were measured with the recoil-distance Doppler shift method in an experiment performed at GANIL. Excited states in ^{98}Zr were populated using the fission reaction between a 6.2  MeV/u ^{238}U beam and a ^{9}Be target. The γ rays were detected with the EXOGAM array in correlation with the fission fragments identified by mass and atomic number in the VAMOS++ spectrometer. Our result shows a very small B(E2;2_{1}^{+}→0_{1}^{+}) value in ^{98}Zr, thereby confirming the very sudden onset of collectivity at N=60. The experimental results are compared to large-scale Monte Carlo shell model and beyond-mean-field calculations. The present results indicate the coexistence of two additional deformed shapes in this nucleus along with the spherical ground state.

Published
2018
Full Text
View/download PDF

20. Lifetime Measurements of Excited States in ^{172}Pt and the Variation of Quadrupole Transition Strength with Angular Momentum.

Author

Cederwall B, Doncel M, Aktas Ö, Ertoprak A, Liotta R, Qi C, Grahn T, Cullen DM, Hodge D, Giles M, Stolze S, Badran H, Braunroth T, Calverley T, Cox DM, Fang YD, Greenlees PT, Hilton J, Ideguchi E, Julin R, Juutinen S, Raju MK, Li H, Liu H, Matta S, Modamio V, Pakarinen J, Papadakis P, Partanen J, Petrache CM, Rahkila P, Ruotsalainen P, Sandzelius M, Sarén J, Scholey C, Sorri J, Subramaniam P, Taylor MJ, Uusitalo J, and Valiente-Dobón JJ

Abstract

Lifetimes of the first excited 2^{+} and 4^{+} states in the extremely neutron-deficient nuclide ^{172}Pt have been measured for the first time using the recoil-distance Doppler shift and recoil-decay tagging techniques. An unusually low value of the ratio B(E2:4_{1}^{+}→2_{1}^{+})/B(E2:2_{1}^{+}→0_{gs}^{+})=0.55(19) was found, similar to a handful of other such anomalous cases observed in the entire Segré chart. The observation adds to a cluster of a few extremely neutron-deficient nuclides of the heavy transition metals with neutron numbers N≈90-94 featuring the effect. No theoretical model calculations reported to date have been able to explain the anomalously low B(E2:4_{1}^{+}→2_{1}^{+})/B(E2:2_{1}^{+}→0_{gs}^{+}) ratios observed in these cases. Such low values cannot, e.g., be explained within the framework of the geometrical collective model or by algebraic approaches within the interacting boson model framework. It is proposed that the group of B(E2:4_{1}^{+}→2_{1}^{+})/B(E2:2_{1}^{+}→0_{gs}^{+}) ratios in the extremely neutron-deficient even-even W, Os, and Pt nuclei around neutron numbers N≈90-94 reveal a quantum phase transition from a seniority-conserving structure to a collective regime as a function of neutron number. Although a system governed by seniority symmetry is the only theoretical framework for which such an effect may naturally occur, the phenomenon is highly unexpected for these nuclei that are not situated near closed shells.

Published
2018
Full Text
View/download PDF

21. Direct Lifetime Measurements of the Excited States in (72)Ni.

Author

Kolos K, Miller D, Grzywacz R, Iwasaki H, Al-Shudifat M, Bazin D, Bingham CR, Braunroth T, Cerizza G, Gade A, Lemasson A, Liddick SN, Madurga M, Morse C, Portillo M, Rajabali MM, Recchia F, Riedinger LL, Voss P, Walters WB, Weisshaar D, Whitmore K, Wimmer K, and Tostevin JA

Abstract

The lifetimes of the first excited 2^{+} and 4^{+} states in ^{72}Ni were measured at the National Superconducting Cyclotron Laboratory with the recoil-distance Doppler-shift method, a model-independent probe to obtain the reduced transition probability. Excited states in ^{72}Ni were populated by the one-proton knockout reaction of an intermediate energy ^{73}Cu beam. γ-ray-recoil coincidences were detected with the γ-ray tracking array GRETINA and the S800 spectrograph. Our results provide evidence of enhanced transition probability B(E2;2^{+}→0^{+}) as compared to ^{68}Ni, but do not confirm the trend of large B(E2) values reported in the neighboring isotope ^{70}Ni obtained from Coulomb excitation measurement. The results are compared to shell model calculations. The lifetime obtained for the excited 4_{1}^{+} state is consistent with models showing decay of a seniority ν=4, 4^{+} state, which is consistent with the disappearance of the 8^{+} isomer in ^{72}Ni.

Published
2016
Full Text
View/download PDF

22. Evolution of collectivity in 72Kr: evidence for rapid shape transition.

Author

Iwasaki H, Lemasson A, Morse C, Dewald A, Braunroth T, Bader VM, Baugher T, Bazin D, Berryman JS, Campbell CM, Gade A, Langer C, Lee IY, Loelius C, Lunderberg E, Recchia F, Smalley D, Stroberg SR, Wadsworth R, Walz C, Weisshaar D, Westerberg A, Whitmore K, and Wimmer K

Abstract

The transition rates from the yrast 2+ and 4+ states in the self-conjugate 72Kr nucleus were studied via lifetime measurements employing the GRETINA array with a novel application of the recoil-distance method. The large collectivity observed for the 4+→2+ transition suggests a prolate character of the excited states. The reduced collectivity previously reported for the 2+→0+ transition was confirmed. The irregular behavior of collectivity points to the occurrence of a rapid oblate-prolate shape transition in 72Kr, providing stringent tests for advanced theories to describe the shape coexistence and its evolution.

Published
2014
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results