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6 results on '"Keatings, J.M."'

1. Identification of excited states in $_{52}^{107}\mathrm{Te}_{55}$

Author

Zhang, W., Cederwall, B., Qi, C., Ertoprak, A., Aktas, Ö., Liu, X., Andgren, K., Auranen, K., Bäck, T., Barber, L., Beeton, G., Cullen, D.M., Darby, I.G., Dimmock, M.R., Eeckhaudt, S., Ganioğlu, E., Górska, M., Grahn, T., Greenlees, P.T., Hadinia, B., Ideguchi, E., Illana, A., Jones, P.M., Joss, D.T., Julin, R., Juutinen, S., Keatings, J.M., Khaplanov, A., Kulali, F., Leino, M., Luoma, M., Lv, B., Nara Singh, B.S., Nelson, L., Niikura, M., Nyman, M., Ojala, J., Page, R.D., Pakarinen, J., Paul, E.S., Petrache, C., Petri, M., Rahkila, P., Ruotsalainen, P., Sandzelius, M., Sarén, J., Scholey, C., Smith, J.F., Sorri, J., Tann, H., Zimba, G., Uusitalo, J., Wadsworth, R., Wyss, R., Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

International audience; Excited states in the extremely neutron-deficient nucleus Te107 have been identified from two separate experiments using the recoil-decay tagging technique. Two connected structures were observed on the basis of γγ-coincidence relations and tentatively assigned as built on the mixed-parentage νg7/2d5/2 and νh11/2 intruder configurations. The observed structures were compared with large-scale shell-model calculations and total Routhian surface calculations. Collective behavior was discovered to persist in the νh11/2 band of Te107 which highlights the shape-polarizing effect of a single valence neutron occupying the h11/2 intruder orbit as the N=50 shell closure is approached.

Published
2021
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2. Structure of high-lying levels populated in the $^{96}$Y $\rightarrow ^{96}$Zr $\beta$ decay

Author

Mashtakov, K.R., Ponomarev, V.Yu., Scheck, M., Finch, S.W., Isaak, J., Zweidinger, M., Agar, O., Bathia, C., Beck, T., Beller, J., Bowry, M., Chapman, R., Chishti, M.M.R., Friman-Gayer, U., Gaffney, L.P., Garrett, P.E., Gregor, E.T., Keatings, J.M., Köster, U., Löher, B., MacLean, A.D., O'Donnell, D., Pai, H., Pietralla, N., Rainovski, G., Ramdhane, M., Romig, C., Rusev, G., Savran, D., Simpson, G.S., Sinclair, J., Sonnabend, K., Spagnoletti, P., Tonchev, A.P., Tornow, W., HEP, INSPIRE, Institut Laue-Langevin (ILL), ILL, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)

Subjects
[PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], High Energy Physics::Experiment, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

The nature of $J^{\pi}=1^-$ levels of $^{96}$Zr below the $\beta$-decay $Q_{\beta}$ value of $^{96}$Y has been investigated in high-resolution $\gamma$-ray spectroscopy following the $\beta$ decay as well as in a campaign of inelastic photon scattering experiments. Branching ratios extracted from $\beta$ decay allow the absolute $E1$ excitation strength to be determined for levels populated in both reactions. The combined data represents a comprehensive approach to the wavefunction of $1^-$ levels below the $Q_{\beta}$ value, which are investigated in the theoretical approach of the Quasiparticle Phonon Model. This study clarifies the nuclear structure properties associated with the enhanced population of high-lying levels in the $^{96}$Y$_{gs}$ $\beta$ decay, one of the three most important contributors to the high-energy reactor antineutrino spectrum.

Published
2020

3. Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive $^{222}\mathrm{Ra}$ and $^{228}\mathrm{Ra}$ Beams

Author

Butler, P.A., Gaffney, L.P., Spagnoletti, P., Abrahams, K., Bowry, M., Cederkäll, J., De Angelis, G., De Witte, H., Garrett, P.E., Goldkuhle, A., Henrich, C., Illana, A., Johnston, K., Joss, D.T., Keatings, J.M., Kelly, N.A., Komorowska, M., Konki, J., Kröll, T., Lozano, M., Nara Singh, B.S., O'Donnell, D., Ojala, J., Page, R.D., Pedersen, L.G., Raison, C., Reiter, P., Rodriguez, J.A., Rosiak, D., Rothe, S., Scheck, M., Seidlitz, M., Shneidman, T.M., Siebeck, B., Sinclair, J., Smith, J.F., Stryjczyk, M., Van Duppen, P., Vinals, S., Virtanen, V., Warr, N., Wrzosek-Lipska, K., Zielińska, M., 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
CERN Lab, nucl-th, Nuclear Theory, Other Fields of Physics, deformation, hep-ph, beam: radioactivity, stability, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucl-ex, physics.atom-ph, rotation, nucleus: transition, Nuclear Physics - Theory, correlation, excited state, Physics::Accelerator Physics, Nuclear Physics - Experiment, Coulomb, Physics::Atomic Physics, Nuclear Experiment, radium: nucleus, Particle Physics - Phenomenology, Nuclear Physics
Abstract

There is sparse direct experimental evidence that atomic nuclei can exhibit stable pear shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole ($E3$) matrix elements have been determined for transitions in $^{222,228}$Ra nuclei using the method of sub-barrier, multi-step Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of $E$3 matrix elements for different nuclear transitions is explained by describing $^{222}$Ra as pear-shaped with stable octupole deformation, while $^{228}$Ra behaves like an octupole vibrator. There is sparse direct experimental evidence that atomic nuclei can exhibit stable pear shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole ($E3$) matrix elements have been determined for transitions in $^{222,228}$Ra nuclei using the method of sub-barrier, multi-step Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of $E$3 matrix elements for different nuclear transitions is explained by describing $^{222}$Ra as pear-shaped with stable octupole deformation, while $^{228}$Ra behaves like an octupole vibrator.

Published
2020
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4. Decay properties of the level 3$^-_1$ in $^{96}$Mo

Author

Gregor, E.T., Arsenyev, N.N., Scheck, M., Shneidman, T.M., Thürauf, M., Bernards, C., Blanc, A., Chapman, R., Drouet, F., Dzhioev, A.A., De France, G., Jentschel, M., Jolie, J., Keatings, J.M., Kröll, Th, Köster, U., Leguillon, R., Mashtakov, K.R., Mutti, P., O'Donnell, D., Petrache, C.M., Simpson, G.S., Sinclair, J., Smith, J.F., Soldner, T., Spagnoletti, P., Sushkov, A.V., Urban, W., Vancraeyenest, A., Vanhoy, J.R., Werner, V., Zell, K.O., Zielińska, M., Institut Laue-Langevin (ILL), ILL, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), 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), 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, Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), 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 Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
High Energy Physics::Experiment, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

International audience; The first excited level of 96Mo was investigated in a high-statistics experiment using the 95Mo(n, γγ) cold neutron capture reaction. The measurements used the high cold neutron flux from the research reactor at Institut Laue-Langevin and employed the highly-efficient EXILL array to detect γ-ray coincidences. The recorded statistics allow identification of decay branches with only a small relative intensity including the E3 decay. With the knowledge of the newly measured branching ratio and the known transition probability, the lifetime of the level was determined and, subsequently, the strength of the other decay branches of the octupole phonon were calculated. The extracted electromagnetic decay strengths are compared to the systematics of the stable even–even molybdenum isotopes and values calculated in a Skyrme-force based quasiparticle random phase approximation and in a cluster approach. Additionally, the decay branch to the low-lying quadrupole isovector level was observed.

Published
2019
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5. A revised B(E2; 2$^{+}_{1} \to 0^{+}_{1}$) value in the semi-magic nucleus $^{210}$Po

Author

Kocheva , D., Rainovski , G., Jolie , J., Pietralla , N., Blazhev , A., Astier , A., Altenkirch , R., Ansari , S., Braunroth , Th., Cortés , M.L., Dewald , A., Diel , F., Djongolov , M., Fransen , C., Gladnishki , K., Hennig , A., Karayonchev , V., Keatings , J.M., Kluge , E., Litzinger , J., Müller-Gatermann , C., Petkov , P., Rudigier , M., Scheck , M., Scholz , Ph., Spagnoletti , P., Spieker , M., Stahl , C., Stegmann , R., Stoyanova , M., Thöle , P., Warr , N., Werner , V., Zell , K.O., Van Isacker , P., Ponomarev , V.Yu., Wölk , D., Witt , W., 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), 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), 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), 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), 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 ), Grand Accélérateur National d'Ions Lourds ( GANIL ), and 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 )

Subjects
Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 25.45.Hi, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 190 ≤ A ≤ 219, Random-phase approximations, 27.80.+w, Nuclear Theory (nucl-th), Electromagnetic transitions, Transfer reactions, 21.60.Jz, 21.10.Tg, 23.20.-g, [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment, [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th]
Abstract

International audience; The lifetimes of the $ 2^+_1$ , the $ 2^+_2$ and the $ 3^-_1$ states of$^{210}$Po have been measured in the$^{208}$Pb($^{12}$C,$^{10}$Be)$^{210}$Po transfer reaction by the Doppler-shift attenuation method. The result for the lifetime of the $ 2^+_1$ state is about three times shorter than the adopted value. However, the new value still does not allow for a consistent description of the properties of the yrast $ 2^+_1$ , $ 4^+_1$ , $ 6^+_1$ , and $ 8^+_1$ states of$^{210}$Po in the framework of nuclear shell models. Quasi-particle Phonon Model (QPM) calculations also cannot overcome this problem thus indicating the existence of a peculiarity which is neglected in both theoretical approaches.

Published
2017
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6. Low collectivity of the ${2}_{1}^{+}$ state of $^{212}\mathrm{Po}$

Author

Kocheva, D., Rainovski, G., Jolie, J., Pietralla, N., Blazhev, A., Altenkirch, R., Ansari, S., Astier, A., Bast, M., Beckers, M., Braunroth, Th., Cappellazzo, M., Dewald, A., Diel, F., Djongolov, M., Fransen, C., Gladnishki, K., Goldkuhle, A., Hennig, A., Karayonchev, V., Keatings, J.M., Kluge, E., Kröll, Th., Litzinger, J., Moschner, K., Müller-Gatermann, C., Petkov, P., Scheck, M., Scholz, Ph., Schmidt, T., Spagnoletti, P., Stahl, C., Stegmann, R., Stolz, A., Vogt, A., Warr, N., Werner, V., Wölk, D., Zamora, J.C., Zell, K.O., Ponomarev, V.Yu., Van Isacker, P., 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), 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), 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), and 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)

Subjects
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

International audience; The lifetime of the $2^+_1$ state of $^{212}$Po was measured in the $^{208}$Pb($^{12}$C,$^{8}$Be)$^{212}$Po transfer reaction by γ -ray spectroscopy employing the recoil distance Doppler shift (RDDS) method. The derived absolute B(E2) value of 2.6(3)W.u. indicates a low collectivity and contradicts previous claims of α-cluster components in the structure of the $2^+_1$ state. It is demonstrated that a consistent description of the properties of the $2^+_1$−$4^+_1$−$6^+_1$−$8^+_1$ sequence in $^{212}$Po cannot be achieved in the framework of a single-j shell-model calculation, either. This puzzle is traced to the properties of the seniority-2 configurations in $^{210}$Pb and $^{210}$Po.

Published
2017
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