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67 results on '"M.-G. Porquet"'

1. Nuclear magic numbers: New features far from stability

Author

O. Sorlin, M.-G. Porquet, 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 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), 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)

Subjects
Nuclear and High Energy Physics, Nuclear Theory, Shell (structure), Stability (learning theory), FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Theoretical physics, Magic number (programming), Bounding overwatch, 0103 physical sciences, Isotonic, Nuclear structure, Tensor, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, nuclear spectroscopy, Physics, 010308 nuclear & particles physics, shell closures, single-particle states, exotic nuclei, magic numbers, Atomic nucleus, Nucleon
Abstract

The main purpose of the present manuscript is to review the structural evolution along the isotonic and isotopic chains around the "traditional" magic numbers 8; 20; 28; 50; 82 and 126. The exotic regions of the chart of nuclides have been explored during the three last decades. Then the postulate of permanent magic numbers was de nitely abandoned and the reason for these structural mutations has been in turn searched for. General trends in the evolution of shell closures are discussed using complementary experimental information, such as the binding energies of the orbits bounding the shell gaps, the trends of the rst collective states of the even-even semi-magic nuclei, and the behavior of certain single-nucleon states. Each section is devoted to a particular magic number. It describes the underlying physics of the shell evolution which is not yet fully understood and indicates future experimental and theoretical challenges. The nuclear mean eld embodies various facets of the Nucleon- Nucleon interaction, among which the spin-orbit and tensor terms play decisive roles in the shell evolutions. The present review intends to provide experimental constraints to be used for the re nement of theoretical models aiming at a good description of the existing atomic nuclei and at more accurate predictions of hitherto unreachable systems., to be published in Prog. Part. Nucl. Phys

Published
2008
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2. A new high-spin level scheme for 149Nd from a fusion-fission reaction

Author

John Durell, M. G. Porquet, Ch. Theisen, Ts. Venkova, M. Houry, R. Lucas, and A. Roach

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Isotope, Excited state, Yrast, Hadron, Nuclear fusion, Atomic physics, Spin (physics), Spectral line
Abstract

A new high-spin level scheme of 149Nd has been identified, which is at variance with the one previously published. The states have been populated in the 12C + 238U fusion-fission reaction at 90MeV bombarding energy and the emitted I³-transitions were detected using the Euroball III array. The yrast band is built on the I½i13/2 sub-shell as in the neighbouring isotones. Moreover, sign of octupole vibrations has been found in 149Nd, as well as in 147Ce, where several new states decaying to the yrast band have been newly observed.

Published
2006
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3. Magnetic dipole bands in : first evidence of excitations across the Z=82 sub-shell in Hg nuclei

Author

F. Hannachi, B. Crowell, A. Korichi, R. V. F. Janssens, T. Lauritsen, F. Azaiez, J.F. Sharpey-Schafer, M. G. Porquet, M. Bergstrom, József Tímár, H. Hübel, I. Ahmad, Nadine Redon, M. P. Carpenter, D. J. Blumenthal, B. J. P. Gall, J.N. Wilson, Ingemar Ragnarsson, R. Wadsworth, A. Lopez-Martens, Anna Wilson, Matthias Meyer, E. S. Paul, D. T. Nisius, Laurent Ducroux, T. L. Khoo, and A. Astier

Subjects
Physics, Nuclear and High Energy Physics, Dipole, Isotope, Proton, Excited state, Potential energy surface, Atomic physics, Spin (physics), Magnetic dipole, Excitation
Abstract

An experiment aimed at studying high-spin states in 190 Hg was performed with the Eurogam II array. The data have revealed the presence of cascades of magnetic dipole transitions with some unexpected properties. Unlike the M1 bands previously observed in the heavier Hg isotopes, these structures have extremely large B(M1)/B(E2) ratios. The observation of a third dipole band with much lower B(M1)/B(E2) values in the same spin/excitation energy regime suggests that the bands may represent configurations occurring in different minima in the potential energy surface. Configuration-dependent Cranked Nilsson–Strutinsky calculations predict the presence of a minimum in the nuclear potential energy surface at a deformation of e≈0.2, γ≈−90°, occurring when a proton is excited across the Z=82 shell-gap into an h9/2 orbital. It is suggested that the bands exhibiting anomalously large B(M1)/B(E2) ratios may be associated with this minimum.

Published
2001
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4. Recent developments of multi e-γ spectrometers

Author

Jean Vanhorenbeeck, John Durell, B. J. Varley, Matthew Jones, Ch. Vieu, T. Rzaca-Urban, A. Minkova, W.R. Phillips, S.J. Dorning, C. Schück, E.B. Kharraja, P.G. Dagnall, E. Gueorguieva, M. Kaci, M. G. Porquet, J. C. S. Bacelar, J.S. Dionisio, Th. Venkova, Michèle Pautrat, A. Passoja, J.M. Lagrange, H. Folger, A. G. Smith, and W. Urban

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Spectrometer, Nuclear spectroscopy, Background suppression, Detector, Electron, Instrumentation, Selection (genetic algorithm), Coincidence
Abstract

A brief introductory survey of gamma-ray detector arrays and in-beam electron spectrometers developed during the last three lustra is followed by a broad discussion of the general requirements for single and multiple in-beam e-gamma spectrometers. A detailed analysis is made of a few important tools for reducing the low-energy electron background (i.e. simultaneous E-Bp selection, true and random coincidence rates, EM static fields around the target region). This survey and discussion are illustrated by the results of several in-beam e-gamma measurements dealing with nuclear spectroscogic investigations of a few medium and heavy nuclei. (C) 1999 Elsevier Science B.V. All rights reserved.

Published
1999
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5. Intrinsic proton states around the superdeformed shell closureZ=80

Author

Y. Le Coz, M. Meyer, J.F. Sharpey-Schafer, S. Bouneau, Christian Bourgeois, János Timár, Faiçal Azaiez, M. Kaci, H. Sergolle, N. Redon, Paul-Henri Heenen, Laurent Ducroux, M. Bergström, M. A. Riley, Isabelle Deloncle, B. J. P. Gall, Ramon Wyss, E. S. Paul, Josette Duprat, M. G. Porquet, Anna Wilson, and Alain Astier

Subjects
Physics, Nuclear and High Energy Physics, Proton, Spin states, Atomic orbital, Closure (mathematics), Shell (structure), Moment of inertia, Atomic physics, Spectroscopy, Signature (topology)
Abstract

High spin states in ${}^{193}\mathrm{Tl}$ have been populated by the ${}^{181}\mathrm{Ta}{(}^{16}\mathrm{O},6n)$ reaction at 110 MeV and \ensuremath{\gamma}-ray spectroscopy was performed using the EUROGAM II array. In addition to the two known superdeformed (SD) bands, three new superdeformed bands have been identified. The dynamic moments of inertia of two of these new bands display a sudden and opposite change of slope and two of them have identical transition energies within 2 keV. The behavior of their dynamic moments of inertia and their \ensuremath{\gamma} transitions allowed us to propose configurations for the proton orbitals involved around the SD shell closure $Z=80.$ The intrinsic proton states identified are the two signature partners of the $[411]1/2$ and the negative signature of the $[651]1/2$ orbitals. Their properties are compared to the predictions of two theoretical calculations.

Published
1998
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7. Isomeric states in 66As

Author

S. Andriamonje, F. Davi, A. Musquère, J. E. Sauvestre, B. Blank, M. Lewitowicz, C. Donzaud, Andreas Martin Heinz, F. Boué, Arnd R. Junghans, M. Karny, A. Grewe, H. Grawe, A. Fleury, Z. Janas, R. Del Moral, M.S. Pravikoff, M. Pfützner, S. Czajkowski, K. Sümmerer, Robert Grzywacz, J.P. Dufour, M. G. Porquet, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-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), 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 Spectrométrie Nucléaire et de Spectrométrie de Masse (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), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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
Physics, Nuclear and High Energy Physics, Decay scheme, Spectrometer, 010308 nuclear & particles physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, medicine.anatomical_structure, Fragmentation (mass spectrometry), 0103 physical sciences, medicine, Atomic physics, 010306 general physics, Nucleus, Excitation
Abstract

Two new isomeric states in the self-conjugate nucleus 66As have been observed at the final focus of the LISE3 spectrometer at GANIL. The nucleus has been produced in a fragmentation reaction of 78Kr at 73A MeV. The 66m1,m2As isomeric levels are placed at excitation energies of E ∗m1 =3023.9 keV and E ∗m2 =1356.7 keV. Half-lives of T1/2m1=17.5(15) μs and T1/2m2=1.9(5) μs have been measured for the isomers and a decay scheme has been established.

Published
1998
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8. A study of fusion - fission atZ= 107

Author

F. Hoellinger, Peter M. Jones, G. Duchêne, F. D. Smit, D. M. Cullen, J.F. Sharpey-Schafer, M. G. Porquet, T Stevens, B. J. P. Gall, Neil Rowley, Anna Wilson, P. A. Butler, R. T. Newman, A. Minkova, T. Kutsarova, S. Naguleswaran, N. Schulz, and J. V. Pilcher

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Fission products, Cold fission, Cluster decay, Neutron emission, Fission, Nuclear Theory, Fission product yield, Nuclear Experiment, Delayed neutron, Fast fission
Abstract

An experiment was performed with the EUROGAM II array to investigate the reaction channels that are open in the fusion of a beam on the actinide target at a series of energies around the Coulomb barrier. The symmetric fission products identified from the level structures seem to suggest that a proton and neutrons are emitted prior to fission.

Published
1997
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9. 31S(p,γ)32Cl reaction in explosive hydrogen burning

Author

J. P. Thibaud, G. Bogaert, A. Lefebvre, P. Aguer, Michael Wiescher, L. Rosier, Joachim Görres, F. de Oliveira, S. Vouzoukas, S. Fortier, M. G. Porquet, J.M. Maison, Andrea Denker, J. Kiener, A. Coc, and Vincent Tatischeff

Subjects
Physics, Nuclear and High Energy Physics, Work (thermodynamics), Explosive material, Hydrogen, Proton, White dwarf, chemistry.chemical_element, Nova (laser), Reaction rate, chemistry, Astrophysics::Solar and Stellar Astrophysics, Atomic physics, Nuclear Experiment, Excitation
Abstract

In the present work we attempted to determine excitation energies and widths of proton unbound states in 32 Cl. These states may contribute as resonances to the 31 S(p,γ) reaction and will determine the reaction rate. Results were used to evaluate the reaction flow in the Si to Ar region obtained by nova outbursts in the case of an ONeMg white dwarf of 1.35 M ⊙ .

Published
1997
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10. Dipole bands in the oblate-shaped195Pb

Author

M. Kaci, H. Sergolle, Marco Meyer, C. W. Beausang, F. Azaiez, N. Redon, N. Poffé, A. G. Smith, A. Korichi, R. Wadsworth, J.F. Sharpey-Schafer, Malcolm J. Joyce, Josette Duprat, M. Aïche, B. J. P. Gall, K. Hauschild, M. G. Porquet, R. Duffait, N. Perrin, G. Bastin, F. Hannachi, R. M. Clark, E. S. Paul, I. Deloncle, C. Bourgeois, J. Simpson, Y. Le Coz, and C. Schück

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Dipole, Spectrometer, Oblate spheroid, Nuclear fusion, Neutron, Atomic physics
Abstract

The nucleus195Pb has been populated with the184W+16O reaction at 113 MeV. Two dipole γ-ray cascades have been observed using the EUROGAM spectrometer. A comprehensive level scheme related to these structures has been established. Multiparticle configurations are attributed to these high-spin structures from detailed comparison with the neighbouring nuclei,193Hg,194Pb and195Tl. Band crossings due to i13/2 neutron pair breaking are observed in195Pb at about the same frequencies as in the isotone193Hg.

Published
1996
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11. Collective and quasiparticle excitations in superdeformedHg190

Author

A. Korichi, D. T. Nisius, T. Lauritsen, Takashi Nakatsukasa, M. Bergström, Laurent Ducroux, T. L. Khoo, A. Lopez-Martens, Anna Wilson, J. N. Wilson, M. P. Carpenter, M. G. Porquet, B. Crowell, B. J. P. Gall, D. J. Blumenthal, F. Azaiez, Iftikhar Ahmad, N. Redon, J.F. Sharpey-Schafer, R. V. F. Janssens, József Tímár, A. Astier, Matthias Meyer, E. S. Paul, and F. Hannachi

Subjects
Physics, Nuclear and High Energy Physics, Yrast, Excited state, Phase (waves), Quasiparticle, Neutron, Moment of inertia, Atomic physics, Random phase approximation, Excitation
Abstract

Superdeformed (SD) states of {sup 190}Hg have been studied with the Eurogam Phase 2 {gamma}-ray spectrometer using the {sup 160}Gd({sup 34}S,4{ital n}) reaction. Two new excited SD bands have been found and identified as belonging to this nucleus, bringing the total number of SD bands in {sup 190}Hg to 4. One of the new bands has a dynamic moment of inertia that is very similar to that of the yrast SD band of {sup 190}Hg and most other SD bands in the {ital A}{approximately}190 region. In contrast, the other band has a dynamic moment of inertia which is mainly constant as a function of rotational frequency and exhibits a dramatic increase at the lowest frequencies. The observed dynamic moments of inertia are compared with the results of random phase approximation calculations based on the cranked shell model. Finally, the known excited SD band has been extended towards lower frequencies and new transitions have been found linking this band to the yrast SD band. The extracted {ital B}({ital E}1) values of the new linking transitions give further support for the possible octupole vibrational character of this band. {copyright} {ital 1996 The American Physical Society.}

Published
1996
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12. Configurations of superdeformed bands inPb193

Author

S. Bouneau, F. Hannachi, Meot, C. Schück, F. Azaiez, N. Redon, N. Poffé, Matthias Meyer, Stephane Perries, Anna Wilson, M. G. Porquet, A. Lopez-Martens, C. Bourgeois, R. Collatz, Le Coz Y, A. Astier, J.F. Sharpey-Schafer, H. Sergolle, A. Korichi, Laurent Ducroux, R. Lucas, B. J. P. Gall, Hibbert I I, R. Wadsworth, Deloncle I I, and R. Duffait

Subjects
Physics, Nuclear and High Energy Physics, Dipole, Branching fraction, Moment of inertia, Atomic physics, Quasi particles, Rotational frequency
Abstract

The six superdeformed bands in {sup 193}Pb have been studied with the EUROGAM 2 {gamma}-ray spectrometer using the {sup 168}Er({sup 30}Si,5{ital n}){sup 193}Pb reaction. The results are discussed in terms of cranked-Hartree-Fock-Bogolioubov-Lipkin-Nogami calculations. From the @FF {sup (2)} moment of inertia behavior as function of the rotational frequency and the {ital M}1 and {ital E}2 decay competition of the superdeformed states, the bands are interpreted as three pairs of signature partners based on quasineutron excitations. Dipole transitions linking two signature partner superdeformed bands have been observed and, for the first time in lead isotopes, the branching ratio {ital B}({ital M}1)/{ital B}({ital E}2)=0.15{plus_minus}0.04 {mu}{sup 2}{sub {ital N}}/{ital e}{sup 2}b{sup 2} has been extracted. {copyright} {ital 1996 The American Physical Society.}

Published
1996
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13. Dipole bands in the oblate-shaped 195 Pb

Author

M. Kaci, M.-G. Porquet, F. Hannachi, M. Aïche, G. Bastin, I. Deloncle, B. J. P. Gall, C. Schück, F. Azaiez, C. W. Beausang, C. Bourgeois, R. M. Clark, R. Duffait, J. Duprat, K. Hauschild, M. J. Joyce, A. Korichi, Y. Le Coz, M. Meyer, E. S. Paul, N. Perrin, N. Poffé, N. Redon, H. Sergolle, J. F. Sharpey-Schafer, J. Simpson, A. G. Smith, and R. Wadsworth

Subjects
Nuclear and High Energy Physics
Published
1996
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14. Rotational high spin structures in doubly-oddAu184

Author

M. E. Debray, F. Ibrahim, M. G. Porquet, H. Sergolle, I. Deloncle, A. Korichi, F. Le Blanc, J. Oms, A. J. Kreiner, Daniel Hojman, Ch. Bourgeois, N. Perrin, A. Knipper, J. Sauvage, G. Marguier, Jorge Davidson, M. Davidson, H. Somacal, and B. Roussière

Subjects
Physics, Nuclear and High Energy Physics, Proton, 010308 nuclear & particles physics, Excited state, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Spectroscopy, Spin (physics), 01 natural sciences
Abstract

Excited states in the doubly-odd{sup 184}Au nucleus have been studied by in-beam {gamma}-ray spectroscopy. This nucleus was produced through the fusion-evaporation reactions {sup 165}Ho({sup 24}Mg, 5{ital n}), {sup 170}Yb({sup 19}F, 5{ital n}), and {sup 161}Dy({sup 27}Al, 4{ital n}). Different rotational band structures have been observed and interpreted as specific couplings of proton and neutron single-particle excitations present in neighboring odd Au and Pt nuclei. {copyright} {ital 1996 The American Physical Society.}

Published
1996
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15. Thei132proton intruder orbital in the superdeformedTl193nucleus: Effective magnetic moment and blocking of proton pairing

Author

J. Duprat, H. Sergolle, F. Azaiez, N. Redon, S. Pilotte, M. G. Porquet, Laurent Ducroux, C. Bourgeois, J.F. Sharpey-Schafer, M. Bergstrom, Y. Le Coz, N. Perrin, E. S. Paul, C. Schück, Marco Meyer, Ramon Wyss, Anna Wilson, S. Bouneau, F. Hannachi, M. A. Riley, B. J. P. Gall, Alain Astier, M. Kaci, János Timár, A. Lopez-Martens, I. Deloncle, and A. Korichi

Subjects
Physics, Nuclear and High Energy Physics, symbols.namesake, Pauli exclusion principle, Magnetic moment, Proton, Yrast, Pairing, symbols, Saturation (graph theory), Moment of inertia, Atomic physics, Omega
Abstract

From the observed competition between $M1$ and $E2$ $\ensuremath{\gamma}$ transitions deexciting the states of the two signature partner yrast superdeformed bands in $^{193}\mathrm{Tl}$, the ${i}_{\frac{13}{2}}$ ($\ensuremath{\Omega}=\frac{5}{2}$) intruder proton orbital is found to have $\frac{({g}_{K}\ensuremath{-}{g}_{R})K}{{Q}_{0}}=0.138\ifmmode\pm\else\textpm\fi{}0.008$. A model dependent value of ${g}_{s}^{\mathrm{eff}}=(0.7\ifmmode\pm\else\textpm\fi{}0.2){g}_{s}^{\mathrm{free}}$ is deduced. A saturation of the ${\mathcal{T}}^{2}$ moments of inertia, at rotational frequency $\ensuremath{\hbar}\ensuremath{\omega}g0.32$ MeV, is observed for the two bands. This feature is discussed in terms of exhausted quasineutron alignment in the presence of substantially reduced quasiproton alignment due to Pauli blocking.

Published
1996
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16. New approach in the off-line treatment of high-fold data

Author

I. Deloncle, M. Dziri-Marce, M. G. Porquet, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), 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, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Cascade, 0103 physical sciences, sort, Fold (geology), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, 01 natural sciences, Instrumentation, Algorithm, Off line
Abstract

The data obtained with the new generation of Ge multidetectors, like EUROGAM, can be considered as multidimensional, or high fold, objects. New codes have been written for the handling of these data which remains very delicate. For example the data sort procedure can affect the relative intensities of γ -rays belonging to rare and long cascade of transitions, as a superdeformed band. A new code, FANTASTIC, devoted to the treatment of high-fold data, offers the possibility to perform such sensitive analyses as, for instance, the study of relative intensities or angular distributions of γ -transitions.

Published
1995
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17. Relative spins and excitation energies of superdeformed bands inHg190: Further evidence for octupole vibration

Author

T. Lauritsen, M. P. Carpenter, B. Crowell, Takashi Nakatsukasa, A. Korichi, D. T. Nisius, T. L. Khoo, R. V. F. Janssens, D. J. Blumenthal, Alain Astier, E. S. Paul, B. J. P. Gall, I. Ahmad, Anna Wilson, F. Hannachi, A. Lopez-Martens, L. du Croux, M. G. Porquet, Marco Meyer, N. Redon, F. Azaiez, J. Timár, and J.F. Sharpey-Schafer

Subjects
Physics, Nuclear and High Energy Physics, Spins, Spectrometer, 010308 nuclear & particles physics, Phase (waves), 01 natural sciences, Vibration, Dipole, Excited state, 0103 physical sciences, Atomic physics, 010306 general physics, Spin (physics), Excitation
Abstract

An experiment using the Eurogam phase II \ensuremath{\gamma}-ray spectrometer confirms the existence of an excited superdeformed (SD) band in $^{190}\mathrm{Hg}$ and its very unusual decay into the lowest SD band over 3--4 transitions. The energies of the transitions linking the two SD bands have been firmly established, and their angular distributions are consistent with a dipole character. Comparisons with calculations using random-phase approximation indicate that the excited SD band can be interpreted as an octupole-vibrational structure.

Published
1995
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18. Spectroscopy of26F

Author

F. Azaiez, C. N. Timis, D. Guillemaud-Mueller, M. Stanoiu, G. Sletten, B. A. Brown, P. Roussel-Chomaz, J. Mrazek, Zs. Podolyák, F. Ibrahim, M. G. Porquet, Zs. Fülöp, S. M. Lukyanov, Ch. Bourgeois, Z. Elekes, A. Krasznahorkay, F. Negoita, H. Savajols, M. G. Saint-Laurent, O. Sorlin, S. Grévy, Zs. Dombrádi, János Timár, M. Lewitowicz, Andras Kerek, Yu. E. Penionzhkevich, C. Borcea, Dóra Sohler, 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), 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), CSNSM SNO, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (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)-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), 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), 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)-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)

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, SHELL model, 13.75.Cs, 13.85.-t, 23.20.Lv, 21.60.Cs, Parity (physics), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, medicine.anatomical_structure, Excited state, 0103 physical sciences, medicine, Atomic physics, 010306 general physics, Spectroscopy, Ground state, Nuclear Experiment, Nucleus
Abstract

The structure of the weakly-bound $^{26}_{\;\;9}$F$_{17}$ odd-odd nucleus, produced from $^{27,28}$Na nuclei, has been investigated at GANIL by means of the in-beam $\gamma$-ray spectroscopy technique. A single $\gamma$-line is observed at 657(7) keV in $^{26}_{9}$F which has been ascribed to the decay of the excited J=$2^+$ state to the J=1$^+$ ground state. The possible presence of intruder negative parity states in $^{26}$F is also discussed., Comment: 3 pages, 1 figure, accepted for publication in Physical Review C

Published
2012
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19. M1 transitions between superdeformed states in 195Tl: the fingerprint of the proton intruder orbital

Author

M. Aïche, R. Duffait, I. Deloncle, A. Korichi, F. Hannachi, M. G. Porquet, R. Wadsworth, C. Bourgeois, R. M. Clark, F. Azaiez, Malcolm J. Joyce, N. Perrin, J. Simpson, C. W. Beausang, I. M. Hibbert, N. Poffé, W.H. Kelly, Josette Duprat, S.J. Gale, J.F. Sharpey-Schafer, B. J. P. Gall, M. Kaci, H. Sergolle, M. Meyer, N. Redon, Y. Le Coz, and C. Schück

Subjects
Physics, Nuclear and High Energy Physics, Dipole, Photon, Spectrometer, Yrast, Nuclear Theory, Quadrupole, Atomic physics, Nuclear Experiment, Excitation
Abstract

Dipole transitions linking the superdeformed Yrast signature-partner bands in 195Tl have been observed using the EUROGAM 1 spectrometer. From the measurements of the photon decay branching ratios, taken together with the average quadrupole moment measured in neighbouring superdeformed nuclei, we find that the two signature partner superdeformed bands involve the excitation of the 81 st proton into the i 13 2 Ω= 5 2 intruder orbital

Published
1994
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20. The N = 7 unfavoured superdeformed band in 193Hg; coriolis splitting and neutron shell structure at extreme deformation

Author

C. A. Kalfas, J.F. Sharpey-Schafer, P.M. Jones, C. Schück, A. Korichi, P.D. Forsyth, N. Fotiades, C. W. Beausang, R. M. Clark, F. Azaiez, Y. Le Coz, Witold Nazarewicz, P. J. Dagnall, Sotirios Harissopulos, S.J. Gale, I. Deloncle, M. G. Porquet, D. M. Cullen, F. Hannachi, R. Vlastou, K. Hauschild, E. S. Paul, R. Wadsworth, P. Fallon, N. Redon, J. Simpson, Malcolm J. Joyce, M. Meyer, M. A. Riley, B. J. P. Gall, and Josette Duprat

Subjects
Physics, Nuclear and High Energy Physics, Mean field theory, Atomic orbital, Deformation (mechanics), Nuclear Theory, Neutron, Atomic physics, Nuclear Experiment
Abstract

A new superdeformed band is reported in 193Hg which has properties that are consistent with it being based on the unfavoured N = 7 (π, α) = (−, +12) intruder orbital. The signature splitting at hω = 200 keV of this intruder orbital and its favoured (−, −12) partner is estimated to be 160±30 keV, which is in agreement with cranked mean field calculations. This band completes the set of low-lying quasi-neutron orbitals predicted to be at the N = 113 superdeformed Fermi-surface. The previously known superdeformed bands in 193Hg have been extended to higher rotational frequencies, hω ⩾ 0.40 MeV.

Published
1994
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22. Two proton high-spin excitations and dipole bands in192Hg

Author

Y. Le Coz, N. Redon, A. Astier, R. Béraud, R. Duffait, M. Meyer, F. Hannachi, G. Bastin, I. Deloncle, B. Gall, M. Kaci, M. G. Porquet, C. Schück, F. Azaiez, C. Bourgeois, J. Duprat, A. Korichi, N. Perrin, N. Poffé, H. Sergolle, J. F. Sharpey-Schafer, C. W. Beausang, S. J. Gale, M. J. Joyce, E. S. Paul, R. M. Clark, K. Hauschild, R. Wadsworth, J. Simpson, M. A. Bentley, A. G. Smith, H. Hübel, P. Willsau, G. De France, I. Ahmad, M. Carpenter, R. Henry, R. V. F. Janssens, T. L. Khoo, T. Lauritsen, Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), Institut de Physique Nucléaire d'Orsay (IPNO), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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 Flores, Sylvie

Subjects
Physics, Nuclear and High Energy Physics, Proton, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], 010308 nuclear & particles physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Dipole, medicine.anatomical_structure, 0103 physical sciences, medicine, Nuclear fusion, Atomic physics, Nuclear Experiment, 010306 general physics, Spin (physics), Beam energy, Nucleus, Excitation
Abstract

The192Hg nucleus was populated in the160Gd(36S, 4n) reaction at a beam energy of E=159 MeV. Emittedγ-rays were detected with the EUROGAM array comprising 43 Compton-suppressed large volume Ge detectors. The level scheme of192Hg has been extended up to an excitation energy of E=10.4 MeV and spin I=34 ħ. Two new structures, made of competing ΔI=1 and ΔI=2 transitions have been observed and their connexions with the low-lying levels established. Their lowest levels are located at 6.304 MeV and 6.879 MeV excitation energy. The experimental results are compared with mean-field HF+BCS calculations. It is proposed that the new structures originate from deformation-aligned quasi-proton excitations π(i13/2 * h9/2)K=11 andπ (h9/2) K=8 2 , coupled to rotation-aligned quasi-neutron ν(i13/2)n and quasi-proton π(h11/2)2 excitations.

Published
1994
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23. Two-proton high-K oblate structures in194Pb

Author

F. Azaiez, N. Perrin, A. Korichi, V Brindejonc, I. Deloncle, R. Wadsworth, J. Simpson, Malcolm J. Joyce, A. Astier, Marco Meyer, G. Bastin, B. J. P. Gall, F. Hannachi, Josette Duprat, C. Bourgeois, R. M. Clark, J.F. Sharpey-Schafer, M. G. Porquet, N. Redon, A. G. Smith, C. W. Beausang, N. Poffé, H. Sergolle, Y. Le Coz, and C. Schück

Subjects
Physics, Nuclear and High Energy Physics, Proton, 010308 nuclear & particles physics, Isotone, Moment of inertia, 01 natural sciences, Dipole, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Spin (physics), Excitation, High-κ dielectric
Abstract

Two regular dipole gamma -ray cascades have been observed in 194Pb. A comprehensive level scheme related to these structures has been built and first members of rotational bands built on K=8 and K=11 two-proton oblate states have been identified. From the excitation energies, spin values, behaviours of the moments of inertia and alignments, and from the comparison with the isotone 192Hg, multiparticle configurations can be attributed to three high-spin structures of 194Pb built respectively on the 4966 keV, 4334 keV and 6198 keV levels: ( pi 9/2(505) pi 13/2(606))(vi13/2)2, ( pi 9/2(505) pi 13/2(606))(vf5/2vi13/2), ( pi 9/2(505) pi 13/2(606)) (vf5/2(vi13/2)3). Within this interpretation, the regular dipole bands correspond to the presence of two or three i13/2 decoupled neutrons.

Published
1994
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24. Study of the superdeformed band in 194Pb and 192Hg with EUROGAM

Author

J. Simpson, N. Perrin, M. G. Porquet, Malcolm J. Joyce, F. Azaiez, G. Bastin, B. J. P. Gall, A. Astier, S.J. Gale, M. Meyer, C. Schück, N. Poffé, J.F. Sharpey-Schafer, F. Hannachi, P.M. Jones, Y. Le Coz, R. G. Henry, P. J. Dagnall, S. A. Forbes, N. Redon, M. P. Carpenter, P. Willsau, I. Deloncle, R. M. Clark, T. Lauritsen, M. A. Bentley, M. M. Aleonard, A. Korichi, C. Bourgeois, E. S. Paul, C. W. Beausang, G deFrance, H. Sergolle, D. Curien, AG Smith, R. Wadsworth, Josette Duprat, and Padraic G. Fallon

Subjects
Physics, Nuclear and High Energy Physics, Deformation (meteorology), Atomic physics
Abstract

A subset of the Eurogam array has been used to investigate the decay out of the superdeformed (SD) band in 194Pb. Two new band members and a new decay pattern into the low lying states at normal deformation (ND) have been established for this band. In the level scheme at normal deformation, the linking transitions between the previously known floating ΔI = 1 sequence and the lower states have been established for the first time. In this talk we will also report on the preliminary results of the search for the linking transitions between the SD and ND states in 192Hg with the fully operational EUROGAM array.

Published
1993
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25. High-Spin Structures of the Odd-A 97 - 105 43 Tc Isotopes

Author

Stephane Perries, T. Kröll, A. J. Chewter, A. Astier, Josette Duprat, S. Courtin, Ts. Venkova, R. Cunningham, A. Nowak, N. Redon, N. Buforn, R-D Herzberg, N. Schulz, M. Houry, Marco Meyer, E. Piasecki, W. Urban, C. M. Petrache, B. J. P. Gall, P. A. Butler, G. Duchêne, R. Lucas, F. Hoellinger, I. Deloncle, A. Bauchet, N. Amzal, and M. G. Porquet

Subjects
Physics, Nuclear and High Energy Physics, Isotope, Proton, Fission, Yrast, Nuclear Theory, Hadron, General Physics and Astronomy, Nuclear physics, Neutron number, Nuclear fusion, Atomic physics, Nuclear Experiment, Spin-½
Abstract

The 99−105Tc isotopes have been produced at high spin as fission fragments following the fusion reaction 37Cl(170 MeV) + 176Yb and studied with the Euroball3 array. The high-spin structures of 103Tc have been identified for the first time. From the systematics of the yrast states of 97−105Tc, the location of individual proton states can be analyzed as a function of the neutron number.

Published
2001
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26. Relative population of the oblate and prolate structures in187Au

Author

D. Hojman, N. Perrin, A. Korichi, F. Hannachi, M. G. Porquet, C. Bourgeois, D. G. Popescu, H. Sergolle, 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), and Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM)

Subjects
Physics, Nuclear and High Energy Physics, education.field_of_study, 010308 nuclear & particles physics, Population, Prolate spheroid, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 0103 physical sciences, Oblate spheroid, Nuclear fusion, Atomic physics, 010306 general physics, education, Beam energy
Abstract

The population of the oblate and the prolate structures in187Au has been studied using the “Château de Cristal” set-up through the172Yb(19F, 4n) reaction at 90, 95 and 100 MeV beam energy. γ — γ, γ-Fold and γ -Sum energy coincidence measurements were performed, γ-ray intensity measurements showed that as the beam energy increases the prolate system is less populated than the oblate one. Fold and Sum-energy associated with oblate and prolate structures showed a different behaviour with increasing beam energy. Two mechanisms are suggested to explain these results.

Published
1992
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27. High-spin study of186Hg

Author

C. Bourgeois, A. Korichi, G. Bastin, M. G. Porquet, H. Sergolle, F. Beck, and N. Perrin

Subjects
Physics, Nuclear and High Energy Physics, Nuclear magnetic resonance, 010308 nuclear & particles physics, Gamma ray spectrometer, 0103 physical sciences, Atomic physics, 010306 general physics, Spin (physics), 01 natural sciences, 3. Good health
Abstract

A detailed spectroscopic study of 186Hg has been performed using the 'Chateau de Cristal' 4 pi gamma spectrometer. High-spin levels of 186Hg are established up to spin 27h(cross). Several negative-parity bands are proposed. Properties of bands of 186Hg are compared to those of neighbouring nuclei.

Published
1992
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28. High-spin structure ofTl189: Role ofh9/2protons in the prolate minimum of light Hg isotopes

Author

Jorge Davidson, M. E. Debray, M. G. Porquet, Ch. Bourgeois, A. Korichi, G. Falcone, F.A. Beck, H. Sergolle, Vito R. Vanin, N. Perrin, H. Mosca, J.C. Merdinger, F. Hannachi, A. J. Kreiner, and G. Bastin

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Proton, Hadron, Nuclear structure, Spin structure, Atomic physics, Nucleon, Spectroscopy, Spectral line
Abstract

High-spin states in $^{189}\mathrm{Tl}$ have been populated through the $^{165}\mathrm{Ho}$${(}^{28}$Si,4n) reaction and studied with in-beam \ensuremath{\gamma}-ray spectroscopy techniques. Both oblate and prolate structures associated with the i13/2 proton orbit are confirmed and extended to higher spins (19/2 and 41/2, respectively). However, only the oblate structure related to the \ensuremath{\pi}h9/2 has been observed meaning that the associated prolate structure is nonyrast contrary to expectation. This experimental result points clearly to a large amplitude of (\ensuremath{\pi}h9/2${)}^{2}$ in the wave function of the prolate minimum of $^{188}\mathrm{Hg}$.

Published
1991
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29. High-spin structures observed in the 101Tc fission fragment

Author

N. Schulz, B. J. P. Gall, T. Kutsarova, A. Minkova, S. Courtin, F. Hoellinger, I. Deloncle, Josette Duprat, M. G. Porquet, H. Sergolle, Andrew A. Wilson, R. Lucas, and C. Gautherin

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Fission, Excited state, Nuclear Theory, Gamma ray, Nuclear fusion, Atomic physics, Nuclear Experiment, Spin (physics), Spectral line, Excitation
Abstract

High-spin states have been studied in 101Tc produced as a fission fragment in the reaction 176Yb +28Si at 145 MeV. Gamma rays were detected with the EUROGAM2 array. The level scheme of 101Tc has been extended up to 4.2 MeV excitation energy and several band structures are observed. Configurations are assigned to two new bands on the basis of their behaviour and of cranked Hartree-Fock-Bogolyubov calculations.

Published
1999
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30. Spin and parity values of states of dipole bands in 194Pb

Author

N. Perrin, J.S. Dionisio, F. Farget, A. Korichi, Josette Duprat, Y. Le Coz, M. G. Porquet, L. Han, I. Deloncle, Michèle Pautrat, Alain Astier, C. Schück, F. Azaiez, C. Bourgeois, D. Santos, Ch. Vieu, B. J. P. Gall, M. Kaci, H. Sergolle, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (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), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire d'Orsay (IPNO), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-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), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and 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)

Subjects
Physics, Nuclear and High Energy Physics, Dipole, 010308 nuclear & particles physics, 0103 physical sciences, Hadron, Nuclear fusion, Parity (physics), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Atomic physics, 010306 general physics, 01 natural sciences
Abstract

Spin and parity values of the states of two dipole bands in 194Pb have been determined from internal conversion and linear polarisation measurements. The multiparticle configurations assigned previously to these dipole bands are discussed within these results.

Published
1998
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31. First indication of population of superdeformed states by incomplete fusion reactions

Author

Alain Astier, I. Deloncle, Josette Duprat, M. Kaci, H. Sergolle, B. J. P. Gall, D. Prévost, S. Bouneau, N. Redon, M. M. Aleonard, U. J. van Severen, J.F. Sharpey-Schafer, E. Gueorguieva, Marco Meyer, C. W. Beausang, N. Dozié, F. Azaiez, W. Korten, Laurent Ducroux, D. Curien, C. Bourgeois, G. Baldsiefen, M. G. Porquet, and F.A. Beck

Subjects
Physics, Nuclear and High Energy Physics, education.field_of_study, Nuclear Theory, Recoil velocity, Population, Nuclear fusion, Atomic physics, Nuclear Experiment, education, Energy (signal processing)
Abstract

The high-spin normally deformed and superdeformed states of ${}^{194}\mathrm{Hg}$ have been populated in an exit channel of the ${}^{16}{\mathrm{O}+}^{186}\mathrm{W}$ reaction at 110 MeV bombarding energy. The Doppler shift analysis of the energies of the \ensuremath{\gamma} transitions de-exciting both normally deformed and superdeformed states in ${}^{194}\mathrm{Hg}$ indicates a lower recoil velocity of the ${}^{194}\mathrm{Hg}$ nucleus compared to that of the ${}^{196}\mathrm{Pb}$ nucleus obtained from the $6n$ exit channel of the complete-fusion compound nucleus. This suggests that incomplete fusion plays the main role in the population of normally deformed and superdeformed states of ${}^{194}\mathrm{Hg}$ in this reaction.

Published
1997
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32. Superdeformed nuclear matter in nuclei with Z $\geq$ 82 : Magnetic properties and neutron shell gap

Author

H. Hübel, R. Lucas, D. Curien, N. Kintz, G. Duchêne, M. G. Porquet, E. Mergel, S. Neumann, F.A. Beck, N. Nenoff, J. Domscheit, O. Dorvaux, N. Buforn, J.P. Vivien, Anna Wilson, G. Schoenwasser, P. Bednardcyk, I. Deloncle, P. Lautesse, A. Prévost, Alain Astier, B. J. P. Gall, A. Goergen, R. Duffait, A. Bauchet, O. Stezowski, M. Meyer, N. Redon, D. Rossbach, D. M. Cullen, Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), EUROBALL, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-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)

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, Isotope, 010308 nuclear & particles physics, Hadron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear matter, 01 natural sciences, Crosstalk, Nuclear physics, 0103 physical sciences, Quasiparticle, Nuclear fusion, Neutron, Atomic physics, 010306 general physics
Abstract

We report the results of an experiment, realized with the EUROBALL IV spectrometer, in which superdeformed (SD) states have been populated in 197,198Pb nuclei. Crosstalk transitions between two signature partner SD bands in 197Pb have been observed with an established M1 character, giving access to the magnetic properties of the $\nu$ [752]5/2 intruder orbital. Six new SD bands have been identified in 197,198Pb. The results are interpreted in the framework of cranked Hartree-Fock calculations. A mixing between quasi-particle excitations and an octupole vibration is suggested in the two SD isotopes.

Published
2004
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33. High-spin states inAu191: Evidence for triaxial shape?

Author

J. S. Dionisi, C. Schück, E. Gueorguieva, A. Korichi, M. G. Porquet, Ch. Vieu, A. Minkova, F. Hannachi, A. Lopez-Martens, Ramon Wyss, and Mohammed Kaci

Subjects
Physics, Nuclear and High Energy Physics, Electron spectrometer, Proton, Spin states, Omega, Molecular physics, medicine.anatomical_structure, Internal conversion, medicine, Gamma spectroscopy, Nuclear Experiment, Spin (physics), Nucleus
Abstract

The level scheme of Au-191 was considerably extended to high spin using gamma spectroscopy with the Eurogam-II array and internal conversion measurements with the Orsay electron spectrometer. Several bands that appear as strongly coupled were associated with low- Omega configurations in Au-191 . Using total routhian surface and cranked shell model calculations it was shown that these bands have a rotation-aligned nature and are most likely generated by the nonaxiallity of the nucleus induced by the odd proton. The predictions for the presence of such bands in Au-191 and in the oblate nuclei in the Pt-Au-Hg region found excellent agreement with the experimental data, as well as the predictions for their alignments and band-crossing frequencies in Au-191 .

Published
2003
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34. Structure of polonium isotopes at high spin with RFD+Euroball IV

Author

B. Rossé, F. Camera, K. M. Spohr, P. Papka, D. Curien, A. Bracco, M. Brekiesz, M. Meyer, K. Keyes, M. Górska, I. Deloncle, J. Robin, A. Prévost, N. Redon, Alain Astier, W. Mȩczyński, P. Bednarczyk, M. G. Porquet, O. Dorvaux, M. Ziebliński, O. Stezowski, A. Maj, J.P. Vivien, J. E. Bastin, H. Hübel, Kai Zuber, B. J. P. Gall, T. Pawłat, A. Papenberg, J. Styczeń, J. Grȩbosz, Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), 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), EUROBALL, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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 Heyd, Yvette

Subjects
Physics, Nuclear and High Energy Physics, Isotope, Spin states, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], 010308 nuclear & particles physics, General Physics and Astronomy, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Nuclear physics, Recoil, chemistry, 0103 physical sciences, 010306 general physics, Spin (physics), Beam energy, Polonium
Abstract

An experiment has been performed to investigate the structure at high spin of the neutron-deficient polonium isotopes using the Recoil Filter Detector coupled to the EUROBALL IV gamma array. High spin states of 200,201 Po have been populated by the 30 Si +176 Yb reaction at a beam energy of 160 MeV. We report here the performances of the RFD + EUROBALL IV coupling.

Published
2003

35. Cross sections relevant toγ-ray line emission in solar flares:3He-induced reactions on16Onuclei

Author

J. Kiener, Vincent Tatischeff, J. A. Scarpaci, F. Hammache, J. P. Thibaud, Ch. Bourgeois, Josette Duprat, Cécile Engrand, M. G. Porquet, A. Coc, Marlete Assunção, Marin Chabot, A. Lefebvre, N. de Sereville, and M. Gounelle

Subjects
Physics, Nuclear and High Energy Physics, Solar flare, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, 01 natural sciences, Nuclear physics, 0103 physical sciences, Electromagnetic shielding, Electronic anticoincidence, Atomic physics, Nuclear Experiment, 010303 astronomy & astrophysics, Excitation, Line (formation)
Abstract

Gamma-ray production cross sections have been measured for gamma-ray lines copiously emitted in the $^3$He bombardment of $^{16}$O nuclei: the 937, 1042 and 1081 keV lines of $^{18}$F and the 1887 keV line of $^{18}$Ne. Four Ge detectors with BGO shielding for Compton suppression were used to measure the angular distributions of the gamma-rays. The excitation functions have been obtained for $^3$He bombarding energies from 3.7 to 36 MeV. Total cross sections are tabulated for calculations relevant to gamma-ray astronomy. The importance of these lines as diagnosis for the presence and properties of accelerated $^3$He in solar flares is discussed in light of the measured cross sections.

Published
2003
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36. Evidence for deformation in $^{113-116}$Cd isotopes

Author

Stephane Perries, F. Hoellinger, N. Redon, H. Sergolle, E. Gueorguieva, B. J. P. Gall, I. Deloncle, T. Kutsarova, Jean-Arcady Meyer, N. Buforn, R. Lucas, A. Minkova, O. Stezowski, N. Schulz, Ts. Venkova, Alain Astier, A. Bauchet, Marco Meyer, Anna Wilson, Josette Duprat, C. Gautherin, M. G. Porquet, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (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), Institut de Physique Nucléaire d'Orsay (IPNO), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-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, Nuclear and High Energy Physics, Isotope, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Nuclear Theory, Hadron, Prolate spheroid, Deformation (meteorology), 01 natural sciences, 7. Clean energy, Isotopes of cadmium, 0103 physical sciences, Nuclear fusion, Atomic physics, Nuclear Experiment, 010306 general physics, Spin (physics), Nuclear Physics
Abstract

High-spin states in 113-116Cd have been investigated with the fusion-fission reaction 28Si +176Yb at 145 > MeV. The experiment has been performed with the Eurogam2 array. New rotational bands based on two quasi-particle states have been observed for even-even cadmium isotopes. A new level scheme based on the 11/2− isomeric state is proposed for 115Cd and the one of 113Cd has been extended to spin (31/2−). The decoupled bands identified in both odd-A nuclei are interpreted as being built upon a low-Ωh11/2 quasi-neutron configuration. Microscopic Hartree-Fock + BCS calculations confirm the prolate deformation in this mass region especially for the odd cadmium isotopes.

Published
2000
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37. Decay-out of the yrast superdeformed band in136Nd: Towards an experimental extraction of the neutron pairing gap at large deformation

Author

C. A. Ur, D. Foltescu, Zs. Podolyák, C. M. Petrache, Laurent Ducroux, N. Redon, S. Frattini, A. Johnson, M. De Poli, Bo Cederwall, M. Lunardon, A. Bracco, G. Viesti, CR Alvarez, S. Leoni, Napoli, Ramon Wyss, A. Astier, M. G. Porquet, S. Lunardi, Claes Fahlander, G. Falconi, R. Venturelli, I. Deloncle, G. de Angelis, Matthias Meyer, D. Bazzacco, A. Gadea, Stephane Perries, and E. Farnea

Subjects
Physics, Nuclear and High Energy Physics, Large deformation, Isotope, Yrast, Nuclear Theory, Parity (physics), Nuclear physics, Pairing, Major conclusion, Neutron, Atomic physics, Nuclear Experiment, Excitation
Abstract

A study of the Nd-136 nucleus has been performed with the EUROBALL III multidetector to establish the decay-out of the yrast superdeformed (SD) band. Three discrete linking transitions (754, 1456, and 1493 keV) have been discovered, establishing the position of the SD band at 7.03 MeV excitation energy with proposed spin and parity 17((-)) for the lowest observed SD state. Neutron pairing gap parameters for SD shapes have been extracted in Nd isotopes, using the strong-coupling model and odd-even mass difference formulas. The major conclusion of our phenomenological analysis is that the pairing correlations do subsist in the SD configurations of nuclei in the A = 130 mass region. [S0556-2813(99)01312-6].

Published
1999
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38. Decay-out of the yrast superdeformed band in 136Nd: towards an experimental extraction of the neutron pairing gap in the second well

Author

D. Bazzacco, Claes Fahlander, S. Leoni, M. G. Porquet, Alain Astier, N. Redon, C. M. Petrache, D. R. Napoli, S. Lunardi, Stephane Perries, Zs. Podolyák, G. Viesti, Bo Cederwall, M. Lunardon, Marco Meyer, A. Johnson, Ramon Wyss, A. Bracco, C. Rossi Alvarez, M. De Poli, G. Falconi, Laurent Ducroux, I. Deloncle, G. de Angelis, R. Venturelli, S. Frattini, A. Gadea, E. Farnea, C. A. Ur, D. Foltescu, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (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), and Flores, Sylvie

Subjects
Physics, Nuclear and High Energy Physics, Isotope, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], 010308 nuclear & particles physics, Yrast, Nuclear Theory, Extraction (chemistry), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, mixture models, Pairing, textual data analysis, 0103 physical sciences, Physics::Atomic and Molecular Clusters, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Spin (physics), Excitation, clustering
Abstract

The automatic clustering of text segments into thematically homogeneous groups is a difficult problem. In this paper, we study the performance of a simple probabilistic model, the "monomaniac" model. We first describe the model and the related EM-based estimation procedures; an application of this model to a English corpus of texts imported from the CKM ("Customer Knowledge Management") literature is then presented.

Published
1999

39. Subshell closure study at N=40 by Coulomb excitation and $\beta$-decay

Author

C. Donzaud, G. Canchel, Yu-E. Penionzhkevich, J. M. Daugas, F. Pougheon, C. Borcea, A. Gillibert, J. S. Winfield, M. G. Saint-Laurent, A. Emsalem, M. Belleguic, S. Leenhardt, R. Béraud, C. Longour, J. C. Angélique, D. Guillemaud-Mueller, F. Azaiez, A.C. Mueller, J. Kiener, Josette Duprat, Eric Chabanat, M. G. Porquet, I. Deloncle, J. E. Sauvestre, F. Marie, Yu. Sobolev, S. Grévy, C. Bourgeois, M. Lewitowicz, O. Sorlin, F. de Oliveira, N. A. Orr, 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), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), 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), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-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), 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), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Frois B.

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, 0103 physical sciences, Closure (topology), Coulomb excitation, Atomic physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, 01 natural sciences, ComputingMilieux_MISCELLANEOUS
Abstract

NESTER; International audience

Published
1998
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40. Decay from superdeformed yrast states to normal deformed states in $^{193}$Tl

Author

Anna Wilson, János Timár, N. Redon, Y. Le Coz, M. G. Porquet, M. A. Riley, J.F. Sharpey-Schafer, I. Deloncle, Laurent Ducroux, M. Bergström, M. Kaci, H. Sergolle, Alain Astier, Marco Meyer, B. J. P. Gall, Ramon Wyss, S. Bouneau, F. Azaiez, E. S. Paul, Josette Duprat, C. Bourgeois, 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), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-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), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, High energy, spatial metaphor, 010308 nuclear & particles physics, Yrast, Nuclear Theory, Hadron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], mental representations, 01 natural sciences, medicine.anatomical_structure, 0103 physical sciences, medicine, Nuclear fusion, Atomic physics, Nuclear Experiment, 010306 general physics, Spin (physics), Nucleus, Excitation, e-learning
Abstract

Information and Communication Technologies change the way people consider information and knowledge. Their use in e-learning raises orientation problems while navigating within technological devices. First of all, the learner-subject must locate the tools and services at his disposal during all of the training. To help orientation, resorting to the spatial metaphor is frequent. This research is based on results of some empirical survey. It is the opportunity of questioning oneself as to the limits of this type of metaphor by studying mental representations that users may have. Solutions could be brought by making spatial metaphor intervene more as a tool of information processing than as a tool of software localization.

Published
1998

41. Octupole Vibrations of the Superdeformed $^{196}$Pb Nucleus

Author

W. Korten, M. M. Aléonard, Josette Duprat, H. Sergolle, N. Dozié, S. Baldsiefen, C. W. Beausang, H. Hübel, D. Curien, Ch. Bourgeois, J.F. Sharpey-Schafer, U. J. van Severen, Mohammed Kaci, A. Astier, Laurent Ducroux, B. J. P. Gall, S. Bouneau, F. Azaiez, N. Redon, Takashi Nakatsukasa, I. Deloncle, Matthias Meyer, M. G. Porquet, F.A. Beck, 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), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-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), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, Yrast, Nuclear Theory, Hadron, Phase (waves), General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], medicine.anatomical_structure, Excited state, medicine, Atomic physics, Nuclear Experiment, Spin (physics), Nucleus, Excitation
Abstract

The study of the superdeformed (SD)196Pb nucleus has been revisited using the Eurogam Phase 2 spectrometer. All of the three observed excited SD bands were found to decay to the yrast SD band through, presumably,E1 transitions, allowing relative spin and excitation energy assignments. Comparisons with calculations using the random-phase approximation suggest that all three excited bands can be interpreted as octupole vibrational structures.

Published
1997

42. New results on the superdeformed $^{196}$Pb nucleus: decay of the excited bands to the yrast band

Author

J.F. Sharpey-Schafer, D. Curien, M. M. Aleonard, C. Bourgeois, G. Baldsiefen, Laurent Ducroux, Takashi Nakatsukasa, Alain Astier, N. Dozié, N. Redon, W. Korten, S. Bouneau, M. Kaci, H. Sergolle, H. Hübel, B. J. P. Gall, Josette Duprat, Marco Meyer, C. W. Beausang, U. J. van Severen, F. Azaiez, I. Deloncle, M. G. Porquet, F.A. Beck, 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), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-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), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Isotope, 010308 nuclear & particles physics, Yrast, Gamma ray, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, medicine.anatomical_structure, Excited state, 0103 physical sciences, medicine, Nuclear fusion, Atomic physics, 010306 general physics, Nucleus, Radioactive decay
Abstract

The study of the superdeformed 196Pb nucleus has been revisited using the EUROGAMphase 2 array. In addition to the known yrast and two excited SD bands, a third excited SD band has been found. All of the three excited bands were found to decay to the yrast SD band through presumably E1 transitions. Comparisons with calculations using RPAapproximation indicate that the excited bands can be interpreted as octupole-vibrational structures.

Published
1996

43. Dipole bands and multi-quasiparticle excitations in $^{193}$Pb

Author

V. Méot, N. Poffé, M. G. Porquet, I. Deloncle, Stephane Perries, C. Bourgeois, Anna Wilson, R. Duffait, Y. Le Coz, Marco Meyer, R. Wadsworth, A. Astier, A. Lopez-Martens, C. Schück, I. M. Hibbert, F. Azaiez, F. Hannachi, R. Collatz, J.F. Sharpey-Schafer, A. Korichi, Laurent Ducroux, B. J. P. Gall, S. Bouneau, N. Redon, H. Sergolle, R. Lucas, Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), Institut de Physique Nucléaire d'Orsay (IPNO), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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 Lorgeril, Jocelyne

Subjects
Physics, Nuclear and High Energy Physics, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], 010308 nuclear & particles physics, Shell (structure), Fermi surface, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Dipole, Atomic orbital, 0103 physical sciences, Quasiparticle, Nuclear fusion, Atomic physics, Spin (physics), 010306 general physics, Excitation
Abstract

The nucleus 193Pb was populated via the 168Er(30Si,5n) reaction at a beam energy of 159 MeV and studied with the EUROGAM II spectrometer. Five new dipole Δ I = 1 cascades have been found. These structures have been connected to the level scheme which has been considerably extended up to a spin of ħ and an excitation energy of about 8 MeV. Angular distribution coefficients, a2, have been measured and confirm the dipole character of the in-band transitions. B(M1)/B(E2) ratios have been extracted for the two most intense cascades. The 193Pb dipole bands are discussed in comparison with those known in odd lead isotopic series and the structure of the band heads is analyzed in terms of microscopic HF+BCS calculations. The proposed configurations are based on a high-K two quasiproton excitation, π ([505]9/2t? ⊗ [606]13/2+)K=11t-, coupled to one or three rotation aligned quasineutrons involving the i13/2, p3/2, f5/2 and/or h{9/2} subshells. The main difference, compared with the heavier lead isotopes, is the presence of large Ω orbitals from the ν (i13/2) shell near the Fermi surface which are responsible for the increasing band-head spin as A decreases.

Published
1996

44. Lifetimes of a dipole cascade in $^{192}$Hg

Author

H. Hübel, N. Redon, M. Neffgen, Marco Meyer, J. R. Hughes, W. Korten, C. W. Beausang, P. Willsau, Jayne Simpson, A. Korichi, F. Hannachi, M. G. Porquet, Y. Le Coz, M. Kaci, E. S. Paul, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (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), Institut de Physique Nucléaire d'Orsay (IPNO), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, Spins, 010308 nuclear & particles physics, 010102 general mathematics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Dipole, Cascade, 0103 physical sciences, Nuclear fusion, 0101 mathematics, Atomic physics, 010306 general physics, Spin (physics)
Abstract

Lifetimes of ten states with spins between 23 and 32 have been measured in a cascade of dipole transitions in 192Hg using the Doppler-shift recoil-distance method. Average reduced transition probabilities, deduced from the lifetimes, are B(M1) ≈ 0.01 and 1.1 μ 2 in the lower and higher spin region of the cascade, respectively, and B(E2) ≈ 0.13 (eb 2. The jump in the B(M1) values can be explained by different multi-quasiparticle configurations in the lower and higher spin regions of the band.

Published
1996

45. Superdeformation in bismuth

Author

F. Azaiez, F. S. Stephens, D. T. Vo, J.F. Sharpey-Schafer, W. H. Kelly, Anna Wilson, M. A. Stoyer, I. Deloncle, J. A. Becker, A. O. Macchiavelli, M. A. Deleplanque, S. Bouneau, S. J. Asztalos, R. M. Clark, L. A. Bernstein, R. M. Diamond, L. P. Farris, Josette Duprat, M. J. Brinkman, P. Fallon, Bo Cederwall, I. Y. Lee, M. G. Porquet, J. R. Hughes, E. A. Henry, 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), and Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM)

Subjects
Physics, Nuclear and High Energy Physics, Angular momentum, Proton, 010308 nuclear & particles physics, chemistry.chemical_element, Moment of inertia, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Bismuth, Superdeformation, symbols.namesake, Pauli exclusion principle, chemistry, 0103 physical sciences, symbols, Gammasphere, Neutron, Atomic physics, 010306 general physics
Abstract

High angular momentum states in {sup 195{minus}197}Bi are populated in two reactions: {sup 183}W({sup 19}F,{ital xn}){sup 202{minus}{ital x}}Bi and {sup 181}Ta({sup 20}Ne,{ital xn}){sup 201{minus}{ital x}}Bi at beam energies of 108 and 123 MeV, respectively. Gamma rays were detected using the Gammasphere array. Three weakly populated rotational sequences have been found. They each have properties characteristic of other superdeformed bands in this mass region. On the basis of cross-bombardment information we believe that one band belongs to each of {sup 195}Bi, {sup 196}Bi, and {sup 197}Bi. The properties of the bands in the odd-Bi nuclei are best reproduced if the odd proton occupies the favored signature of the [651]1/2 orbital, while the band in {sup 196}Bi has this same proton configuration coupled to an additional {ital N}=7 ({ital j}{sub 15/2}) neutron. The relative behavior of the @F {ital I}{sup (2)} moments of inertia can be qualitatively understood in terms of Pauli-blocking effects. {copyright} {ital 1996 The American Physical Society.}

Published
1996

46. Observation and lifetime of the first excited superdeformed band in $^{192}$Hg

Author

A. Korichi, M. Kaci, H. Sergolle, T. L. Khoo, R. M. Clark, Josette Duprat, E. S. Paul, H. Hübel, J. Simpson, M. Meyer, A. G. Smith, I. Ahmad, Y. Le Coz, R. Wadsworth, N. Redon, W. Korten, C. W. Beausang, G. Bastin, N. Poffé, Malcolm J. Joyce, M. G. Porquet, R. Duffait, F. Hannachi, F. Azaiez, J.F. Sharpey-Schafer, B. J. P. Gall, C. Schück, T. Lauritsen, C. Bourgeois, R. V. F. Janssens, I. Deloncle, R. G. Henry, M. P. Carpenter, N. Perrin, P. Willsau, 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), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-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), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, 010308 nuclear & particles physics, Attenuation, Electronic structure, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, medicine.anatomical_structure, Excited state, 0103 physical sciences, Quadrupole, medicine, Atomic physics, 010306 general physics, Nucleus, Excitation
Abstract

An excited superdeformed (SD) band has been observed in 192Hg with the UROGAM spectrometer. It is interpreted as a two quasi-neutron excitation in the 192Hg SD nucleus. Nuclear level lifetimeshave been measured using the Dopple-shift attenuation method. An average transition quadrupole moment of 19.5 ± 1.5 b has been obtained which is similar to the value measured in the yeast SD band. These results indicate that the deformation in the 192Hg SD nucleus is stable despite changes in the occupancy of high-N-orbitals.

Published
1995

47. Confirmation of the existence of a superdeformed rotational band in $^{192}$Pb

Author

R. Collatz, J.F. Sharpey-Schafer, M. Kaci, H. Sergolle, R. Lucas, J.P. Vivien, Alain Astier, D. Goutte, I. Deloncle, M. G. Porquet, R. Béraud, F.A. Beck, C. Bourgeois, G. Duchêne, R. Duffait, A. Lopez-Martens, A. Korichi, Anna Wilson, R. Wadsworth, Y. Le Coz, B. Haas, Marco Meyer, S. Perries, I. M. Hibbert, D. Curien, F. Azaiez, Josette Duprat, C. Schück, N. Poffé, F. Hannachi, S. Bouneau, V. Méot, L. Ducroux, B. J. P. Gall, N. Perrin, N. Redon, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (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), Institut de Physique Nucléaire d'Orsay (IPNO), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-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, Nuclear and High Energy Physics, Spectrometer, 010308 nuclear & particles physics, 0103 physical sciences, Nuclear fusion, Atomic physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, 01 natural sciences
Abstract

A controversy has arisen over the existence, or not, of a superdeformed rotational band in192Pb. We have carried out an experiment using the168Er(3OSi, 6n)192Pb reaction at 159 MeV and have observed the coincidentγ rays in the EUROGAM 2 spectrometer. We confirm the original result of Henry et al. that a superdeformed band exists in192Pb.

Published
1995

48. Superdeformation in the bismuth nuclei

Author

A. O. Macchiavelli, F. S. Stephens, S. J. Asztalos, J.F. Sharpey-Schafer, F. Azaiez, Anna Wilson, R. M. Clark, Bo Cederwall, M. A. Deleplanque, J. A. Becker, M. G. Porquet, M. A. Stoyer, D. T. Vo, J. R. Hughes, E. A. Henry, L. P. Farris, Josette Duprat, P. Fallon, S. Bouneau, W. H. Kelly, I. Y. Lee, R. M. Diamond, Lorgeril, Jocelyne, 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), and Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM)

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Angular momentum, Isotope, 010308 nuclear & particles physics, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Electromagnetic radiation, Bismuth, Superdeformation, medicine.anatomical_structure, chemistry, 0103 physical sciences, medicine, Gammasphere, Atomic physics, 010306 general physics, Nucleus, Nuclear Physics
Abstract

High angular-momentum states in [sup 196,197]Bi were populated in the reaction [sup 183]W ([sup 19]F,[ital xn]) at a beam energy of 108 MeV, and [gamma] rays were detected with the Gammasphere array. Two weakly populated rotational bands, with energy spacings characteristic of superdeformation have been found. Both cascades can be assigned unambiguously to the Bi nuclei; however, their isotopic assignment to [sup 197]Bi is tentative. The properties of the bands and their possible structures are discussed. Our results represent the first identification of superdeformed bands in a nucleus of the [ital A][similar to]190 mass region with [ital Z][gt]82.

Published
1995

49. Structure of low-spin states in $^{186}$Ir

Author

C. Bourgeois, P. Kilcher, F. Le Blanc, J. Sauvage, A. J. Kreiner, B. Roussière, A. Ben Braham, M. G. Porquet, 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), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), and ISOCELE

Subjects
Physics, Nuclear and High Energy Physics, Relative intensity, Spin states, 010308 nuclear & particles physics, 0103 physical sciences, State (functional analysis), Atomic physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, Ground state, 01 natural sciences
Abstract

Low-spin states of 186 Ir populated through the β + /EC decay of 186 Pt nuclei were studied using mass-separated sources and γ-ray and e − spectroscopic techniques. A completely new level scheme of 186 Ir is established. It is shown that the 2 − isomeric state is located at an energy less than 1.5 keV above the 5 + ground state. A very low-energy transition from the 2 − isomer to the 5 + ground state has to exist in order to explain the data, and its relative intensity has been estimated to be around 25% of the total decay of the 2 − state. Most of the experimental levels are interpreted within the two-quasiparticle-plus-rotor model.

Published
1991

50. High spin investigation in 193Pb with EUROGAM 2: coexistence of superdeformed and dipole bands

Author

C. Schück, B. J. P. Gall, R. Collatz, S. Perries, J.F. Sharpey-Schafer, Y. Le Coz, C. Bourgeois, M. G. Porquet, A. Korichi, S. Bouneau, Laurent Ducroux, A. Lopez-Martens, R. Duffait, R. Wadsworth, F. Hannachi, H. Sergolle, I. Deloncle, N. Poffé, R. Lucas, N. Redon, Marco Meyer, I. M. Hibbert, F. Azaiez, Anna Wilson, Alain Astier, and V. Méot

Subjects
Physics, Nuclear and High Energy Physics, Dipole, Spectrometer, Isotope, Ratio value, Nuclear fusion, Atomic physics, Rotation, Spin (physics), Excitation
Abstract

The nucleus 193Pb was populated via the 168Er(30Si, 5n) reaction at a beam energy of 159 MeV and studied with the EUROGAM II spectrometer. Five new dipole ΔI = 1 cascades have been found. The 193Pb dipole bands are discussed in terms of microscopic HF+BCS calculations. The proposed configurations are based on a high-K two-quasiproton excitation coupled to rotation aligned quasineutrons. Parallel to the dipole bands the six superdeformed bands have been discussed in the framework of microscopic mean-field calculations. The bands are interpreted as three pairs of signature partners based on quasineutron excitations. Cross-talk transitions linking two signature partner superdeformed bands have been observed and, for the first time in lead isotopes, a mean B(M1)/B(E2) ratio value of 0.15±0.04 μ N 2 /e2b2 has been extracted.

Published
1997
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