49 results on '"Deloncle, I."'
Search Results
2. Electromagnetic dipole and Gamow-Teller responses of even and odd Zr isotopes in QRPA calculations with the D1M Gogny force.
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Deloncle, I., Péru, S., and Martini, M.
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DIPOLE moments , *ZIRCONIUM isotopes , *HARTREE-Fock approximation , *PROTON spin , *NUCLEAR spin - Abstract
In this paper we present theoretical results on the dipole response in the proton spin-saturated Zr isotopes. The electric and magnetic dipole excitations are obtained in Hartree-Fock-Bogolyubov plus Quasi-particle Random Phase Approximation (QRPA) calculations performed with the D1M Gogny force. A pnQRPA charge exchange code is used to study the Gamow-Teller response. The results on the pygmy, the giant dipole resonances as well as those on the magnetic nuclear spin-flip excitation and the Gamow-Teller transitions are compared with available experimental or theoretical information. In our approach, the proton pairing plays a role in the phonon excitations, in particular in the M1 nuclear spin-flip resonance. [ABSTRACT FROM AUTHOR]
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- 2017
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3. Introduction of a valence space in QRPA: impact on vibrational mass parameters and spectroscopy.
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Lechaftois, F., Deloncle, I., and Péru, S.
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COHERENCE (Physics) , *HAMILTONIAN systems , *STOCHASTIC convergence , *ATOMIC transition probabilities , *TIN isotopes - Abstract
For the first time, using a unique finite range interaction (D1M Gogny force), a fully coherent and time-feasible calculation of the Bohr Hamiltonian vibrational mass is envisioned in a Hartree-Fock-Bogoliubov + Quasiparticle Random Phase Approximation (QRPA) framework. In order to reach handable computation time, we evaluate the feasibility of this method by considering the insertion of a valence space for QRPA. We validate our approach in the even-even tin isotopes comparing the convergence scheme of the mass parameter with those of built-in QRPA outputs: excited state energy and reduced transition probability. The seeming convergence of these intrinsic quantities is shown to be misleading and the difference with the theoretical expected value is quantified. This work is a primary step towards the systematic calculation of mass parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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4. Introduction of a valence space in quasiparticle random-phase approximation: Impact on vibrational mass parameters and spectroscopic properties.
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Lechaftois, F., Deloncle, I., and Péru, S.
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VALENCE (Chemistry) , *QUASIPARTICLES , *PARTICLE physics , *QUANTUM theory , *APPROXIMATION theory - Abstract
For the Rrst time, using a unique finite-range interaction (D1M Gogny force), a fully coherent and time-feasible calculation of the Bohr Hamiltonian vibrational mass is envisioned in a Hartree-Fock-Bogoliubov + quasiparticle random-phase approximation (QRPA) framework. In order to reach a reasonable computation time, we evaluate the feasibility of this method by considering two restrictions for the QRPA: the Tamm-Dancoff approximation and the insertion of a valence space. We validate our approach in the even-even tin isotopes by comparing the convergence scheme of the mass parameter with those of built-in QRPA outputs: excited-state energy and reduced transition probability. The seeming convergence of these intrinsic quantities is shown to be misleading and the difference with the theoretical expected value is quantified. This work is a primary step towards the systematic calculation of mass parameters. [ABSTRACT FROM AUTHOR]
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- 2015
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5. B(E2: 01+→21+) behavior around 68Ni : seniority and p-n interaction.
- Author
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Deloncle, I. and Roussière, B.
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NEUTRONS , *PARTICLES (Nuclear physics) , *NUCLEAR physics , *PHYSICS , *NICKEL - Abstract
The B(E2: 01+ → 21+) (B(E2)↑) transition probability of even-even nuclei from 56Ni up to 82Se are confronted with curves obtained in a approximation to the generalized seniority and shown to fit in with a neutron sub-shell closure at N=38 and a scenario involving p-n interaction. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]
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- 2006
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6. Unexpected high-energy γ emission from decaying exotic nuclei.
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Gottardo, A., Verney, D., Deloncle, I., Péru, S., Delafosse, C., Roccia, S., Matea, I., Sotty, C., Andreoiu, C., Costache, C., Delattre, M.-C., Etilé, A., Franchoo, S., Gaulard, C., Guillot, J., Ibrahim, F., Lebois, M., MacCormick, M., Marginean, N., and Marginean, R.
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EXOTIC nuclei , *PARTICLE physics , *NUCLEAR energy , *PHOTOFISSION , *NEUTRON emission - Abstract
The N = 52 Ga 83 β decay was studied at ALTO. The radioactive 83 Ga beam was produced through the ISOL photofission technique and collected on a movable tape for the measurement of γ -ray emission following β decay. While β -delayed neutron emission has been measured to be 56–85% of the decay path, in this experiment an unexpected high-energy 5–9 MeV γ -ray yield of 16(4)% was observed, coming from states several MeVs above the neutron separation threshold. This result is compared with cutting-edge QRPA calculations, which show that when neutrons deeply bound in the core of the nucleus decay into protons via a Gamow–Teller transition, they give rise to a dipolar oscillation of nuclear matter in the nucleus. This leads to large electromagnetic transition probabilities which can compete with neutron emission, thus affecting the β -decay path. This process is enhanced by an excess of neutrons on the nuclear surface and may thus be a common feature for very neutron-rich isotopes, challenging the present understanding of decay properties of exotic nuclei. [ABSTRACT FROM AUTHOR]
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- 2017
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7. Fast-neutron induced background in LaBr3:Ce detectors.
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Kiener, J., Tatischeff, V., Deloncle, I., de Séréville, N., Laurent, P., Blondel, C., Chabot, M., Chipaux, R., Coc, A., Dubos, S., Gostojic`, A., Goutev, N., Hamadache, C., Hammache, F., Horeau, B., Limousin, O., Ouichaoui, S., Prévot, G., Rodríguez-Gasén, R., and Yavahchova, M.S.
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FAST neutrons , *LANTHANUM compounds , *SCINTILLATION counters , *PROTON beams , *SIMULATION methods & models , *PHYSICS research - Abstract
The response of a scintillation detector with a cylindrical 1.5-in. LaBr 3 :Ce crystal to incident neutrons has been measured in the energy range E n = 2–12 MeV. Neutrons were produced by proton irradiation of a Li target at E p = 5–14.6 MeV with pulsed proton beams. Using the time-of-flight information between target and detector, energy spectra of the LaBr 3 :Ce detector resulting from fast neutron interactions have been obtained at 4 different neutron energies. Neutron-induced γ rays emitted by the LaBr 3 :Ce crystal were also measured in a nearby Ge detector at the lowest proton beam energy. In addition, we obtained data for neutron irradiation of a large-volume high-purity Ge detector and of a NE-213 liquid scintillator detector, both serving as monitor detectors in the experiment. Monte-Carlo type simulations for neutron interactions in the liquid scintillator, the Ge and LaBr 3 :Ce crystals have been performed and compared with measured data. Good agreement being obtained with the data, we present the results of simulations to predict the response of LaBr 3 :Ce detectors for a range of crystal sizes to neutron irradiation in the energy range E n = 0.5–10 MeV. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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8. COeCO: A new [formula omitted]-delayed conversion-electron spectroscopy setup for low-energy ISOL beams at the ALTO facility in Orsay.
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Tocabens, G., Delafosse, C., Verney, D., Cantacuzène, E., Cheikh Mhamed, M., Deloncle, I., Didierjean, F., Dong, W., Gaulard, C., Genolini, B., Guillot, J., Hammache, F., Harrouz, S., Ibrahim, F., Jacob, H., Kaci, M., de Lara, A., de Séréville, N., Le Blanc, F., and Lebois, M.
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ELECTRON spectroscopy , *RADIOACTIVE nuclear beams , *URANIUM , *SUPERHEAVY elements , *BETA decay , *SPECTROMETRY , *COPPER , *MAGNETIC fields - Abstract
A new β -decay station, COnversion electrons Chasing at Orsay (COeCO), has been developed at ALTO to perform conversion electron spectroscopy studies of neutron-rich nuclei produced by photo-fission of a uranium carbide target. It is based on the collection of a low-energy ISOL beam on a mylar tape, and the transportation of the electrons emitted by the produced radioactive source through a magnetic field induced by two copper coils, towards a cooled Si(Li) detector. In this article, a detailed description of the new decay station and its components is given. The magnetic field induced by the coils was measured and compared to simulations performed with the COMSOL ® software. The efficiency of the detection setup was estimated using a 207Bi and a 152Eu source as an off-line commissioning. Finally, the results obtained with a 96Rb radioactive beam for the on-line commissioning are presented. [ABSTRACT FROM AUTHOR]
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- 2024
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9. In-Beam γ-Ray Spectroscopy of the N=50 Isotones on the Neutron-Rich Side.
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Prévost, A., Astier, A., Deloncle, I., Porquet, M.-G., Azaiez, F., Buta, A., Curien, D., Dorvaux, O., Duchêne, G., Gall, B. J. P., Khalfallah, F., Piqueras, I., Rousseau, M., Ibrahim, F., Essabaa, S., Meyer, M., Redon, N., Stézowski, O., Venkova, Ts., and Lucas, R.
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HIGH spin physics , *NUCLEAR fission , *CONTROLLED fusion , *NEUTRONS , *NUCLEAR physics , *DELAYED neutrons - Abstract
High-spin states of 84Se, produced as a fission fragment in the fusion-fission reaction 18O+208Pb and studied with the EUROBALL IV array, have been identified for the first time. Their interpretation gives new insights about the evolution of the N=50 shell gap at the vicinity of 78Ni. To characterize this evolution, it would be worth using a new device devoted to the high-spin studies of neutron-rich nuclei produced by asymetric fission modes. Such dedicated studies are reported in a second part. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]
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- 2005
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10. Half-life measurements of Cs excited nuclear states.
- Author
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Roussière, B., Cardona, M., Deloncle, I., Hojman, D., Kiener, J., Petkov, P., Tonev, D., and Venkova, Ts.
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HALF-life (Nuclear physics) , *NUCLEAR excitation , *CESIUM , *XENON , *PHYSICAL measurements , *NUCLEAR spin , *ATOMIC orbitals , *RADIOACTIVE decay , *NUCLEAR fission - Abstract
A fast-timing setup has been developed to measure the nuclear-state half-lives of neutron-rich nuclei. The first on-line measurements were performed on Cs obtained from the β decay of Xe. These neutron-rich Xe nuclei were produced by the U photofission induced by the 50MeV electron beam delivered by the ALTO facility. The half-lives of the first excited state in Cs and of six excited states in Cs were measured for the first time. Taking into account new information given by the deduced transition probabilities, we discuss the structure of the first excited states in Cs : it is shown that, in both nuclei, the first excited $$\tfrac{5} {2}^ +$$ level corresponds mainly to the one-proton state issued from the π2 d orbital and that the most probable spin values for the states located at 289.8, 393.5, and 393.8keV in Cs are $$\tfrac{5} {2}^ +$$, $$\tfrac{3} {2}^ +$$, and $$\tfrac{1} {2}^ +$$, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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11. Transition probabilities in 31P and 31S: A test for isospin symmetry.
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Tonev, D., de Angelis, G., Deloncle, I., Goutev, N., De Gregorio, G., Pavlov, P., Pantaleev, I.L., Iliev, S., Yavahchova, M.S., Bizzeti, P.G., Demerdjiev, A., Dimitrov, D.T., Farnea, E., Gadea, A., Geleva, E., He, C.Y., Laftchiev, H., Lenzi, S.M., Lunardi, S., and Marginean, N.
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ISOBARIC spin , *PARTICLE detectors , *EQUATIONS of motion , *SYMMETRY , *PROBABILITY theory - Abstract
Excited states in the mirror nuclei 31P and 31S were populated in the 1p and 1n exit channels of the reaction 20Ne + 12C, at a beam energy of 33 MeV. The 20Ne beam was delivered for the first time by the Piave-Alpi accelerator of the Laboratori Nazionali di Legnaro. Angular correlations of coincident γ -rays and Doppler-shift attenuation lifetime measurements were performed using the multi-detector array GASP in conjunction with the EUCLIDES charged particle detector. In the observed B(E1) strengths, the isoscalar component, amounting to 24% of the isovector one, provides strong evidence for breaking of the isospin symmetry in the A = 31 mass region. Self-consistent beyond mean field calculations using Equation of Motion method based on a chiral potential and including two- and three-body forces reproduce well the experimental B(E1) strengths, reinforcing our conclusion. Coherent mixing from higher-lying states involving the Giant Isovector Monopole Resonance accounts well for the effect observed. The breaking of the isospin symmetry originates from the violation of the charge symmetry of the two- and three-body parts of the potential, only related to the Coulomb interaction. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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12. New high-spin states of 142 58Ce and 140 56Ba from fusion-fission reactions: Proton excitations in the N = 84 isotones.
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Venkova, Ts., Porquet, M.-G., Deloncle, I., Petkov, P., Astier, A., Prévost, A., Azaiez, F., Bogachev, A., Buta, A., Curien, D., Dorvaux, O., Duchêne, G., Durell, J., Gall, B. J. P., Houry, M., Khalfallah, F., Lucas, R., Meyer, M., Piqueras, I., and Redon, N.
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HADRONS , *NUCLEAR fission , *NUCLEAR reactions , *PARTICLES (Nuclear physics) , *NUCLEAR physics - Abstract
High-spin states in the 142Ce and 140Ba nuclei have been populated in the 12C + 238U and 18O + 208Pb fusion-fission reactions at 90MeV and 85MeV bombarding energy, respectively. The emitted γ -radiation was detected using the Euroball III and IV arrays. The high-spin yrast and near-to-yrast structures of 142Ce have been considerably extended. The level scheme of 140Ba has been extended by six new levels. The newly observed structures in these N = 84 isotones are discussed by analogy with the neighbouring nuclei. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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13. Evolution of the ... multiplet in the neutron-rich 49In isotopes: Evidence for the gradual filling of the neutron sub-shell.
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Porquet, M.-G., Astier, A., Deloncle, I., Dorvaux, O., Gall, B. J. P., Lucas, R., Meyer, M., Prévost, A., Redon, N., Schulz, N., and Stézowski, O.
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ISOTOPES , *NUCLIDES , *PARTICLES (Nuclear physics) , *NEUTRONS , *QUASIPARTICLES , *ATOMS - Abstract
High-spin states from the three-quasiparticle (3qp) configuration &paig9/2vh211/2 in the neutronrich 49In isotopes have been studied in the framework of shell model calculation. The two-body residual interactions needed for such calculations have been extracted from the level schemes of neighbouring nuclei. In particular, the evolution of the proton-neutron &paig9/2vh211/2 interaction has been analyzed as a function of the neutron number. When the gradual filling of the vh211/2 sub-shell is taken into account, the results of the 3qp configuration calculations are found to be very close to the experimental positive-parity yrast states located above 2 MeV excitation energy in 113-121In. Moreover, several long-lived isomeric states with positive parity are predicted in 123, 125, 127In. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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14. Experimental Sign of a Weakening of the N=50 Spherical Shell Gap.
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Prévost, A., Astier, A., Deloncle, I., Porquet, M.-G., Azaiez, F., Buta, A., Curien, D., Dorvaux, O., Duchêne, G., Gall, B. J. P., Khalfallah, F., Piqueras, I., Rousseau, M., Meyer, M., Redon, N., Stézowski, O., Venkova, Ts., Lucas, R., and Bogachev, A.
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PARTICLES (Nuclear physics) , *NUCLEAR physics , *NUCLEAR fusion , *NUCLEAR fission , *NUCLEAR reactions - Abstract
High-spin states of 84Se, produced as a fission fragment in the fusion-fission reaction 18O+208Pb, have been identified for the first time thanks to the EUROBALL IV array. The excitation energies of three of these states, interpreted as being due to the (νg9/2-1 νd5/2+1) neutron-core excitation, give new insights about the evolution of the N=50 shell gap at the vicinity of 78Ni. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2006
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- View/download PDF
15. Symmetries in mirror nuclei 31S and 31P.
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Arsenyev, N., Bezbakh, A., Rogov, I., Shneidman, T., Vdovin, A., Tonev, D., de Angelis, G., Goutev, N., Iliev, S., Orlandi, R., Deloncle, I., Demerdjiev, A., Gadea, A., Geleva, E., He, C., Laftchiev, H., Lunardi, S., Marginean, N., Nikolov, A., and Pavlov, P.
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SYMMETRY (Physics) , *MIRROR nuclei , *EXCITED states , *NUCLEAR reactions , *ISOBARIC spin - Abstract
Excited states in mirror nuclei 31S and 31P were populated in the 1n and 1p exit channels, respectively, of the reaction 20Ne + 12C. The beam of 20Ne, with an energy of 33 MeV, was delivered for the first time by the Piave-Alpi accelerator of the Laboratori Nazionali di Legnaro. Angular correlations of coincident pairs and Doppler-shift attenuation lifetime measurements in 31S and 31P were performed using the multidetector array GASP in conjunction with the EUCLIDES charged particle detector. A comparison of the determined B(E1) strengths of the analog mirror 7/2- → 5/2+ transitions indicates the presence of a violation of isospin symmetry. [ABSTRACT FROM AUTHOR]
- Published
- 2018
16. γ-ray emission in proton-induced nuclear reactions on [formula omitted]C and Mylar targets over the incident energy range, Ep = 30 – 200 MeV. Astrophysical implications.
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Rahma, Y., Ouichaoui, S., Kiener, J., Lawrie, E.A., Lawrie, J.J., Tatischeff, V., Belhout, A., Moussa, D., Yahia-Cherif, W., Benhabiles-Mezhoud, H., Bucher, T.D., Dinoko, T.R.S., Chafa, A., Conradie, J.L., Damache, S., Debabi, M., Deloncle, I., Easton, J.L., Fouka, M., and Hamadache, C.
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NUCLEAR reactions , *COSMIC rays , *NUCLEAR cross sections , *SOLAR flares , *INTERSTELLAR medium , *NUCLEAR shapes - Abstract
We have measured the γ -ray line production cross sections in proton-induced nuclear reactions on various target nuclei (12C, 16O, 24Mg, 28Si, 56Fe) of chemical elements abundant in astrophysical sites (solar flares, the interstellar medium, cosmic compact objects) over the incident energy range of E p = 30 – 200 MeV. We carried out experimental campaigns in joint collaboration at the K = 200 separated sector cyclotron of iThemba LABS using a high-energy resolution, high-efficiency detection array composed of 8 Compton-suppressed clover detectors comprising 32 HP-Ge crystals for recording the γ -ray energy spectra. In the current paper, we focus on γ -ray de-excitation lines produced in proton irradiations of n a t C and Mylar targets, in particular, on the prominent 4.439 and 6.129 MeV lines of 12C and 16O which are among the strongest lines emitted in solar flares and in interactions of low-energy cosmic rays (LECRs) with the gas and dust of the inner galaxy. We report new γ -ray production experimental cross section data for ten nuclear γ -ray lines that we compare to previous low-energy data sets from the literature, to the predictions of the TALYS code of nuclear reactions and to a semi-empirical compilation. In the first approach, performing calculations with default input parameters of TALYS we observed substantial deviations between the predicted cross sections and experimental data. Then, using modified optical model potential (OMP) and nuclear level deformation parameters as input data we generated theoretical excitation functions for the above two main lines fully consistent with experimental data. In contrast, the experimental data sets for the other eight analyzed lines from the two proton-irradiated targets exhibit significant deviations with the predicted cross section values. We also report line-shape experimental data for the line complex observed at E γ = 4.44 MeV in irradiations of the two targets. Finally, we emphasize the astrophysical implications of our results. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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17. On the quadrupole collectivity in the yrast band of 168Yb.
- Author
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Petkov, P., Dewald, A., Möller, O., Deloncle, I., Chapman, R., Pascu, S., Bucurescu, D., Tonev, D., Reese, M., Fransen, C., Araddad, S.Y., Asova, G., Copnell, J., Goutev, N., Hackstein, M., Jolie, J., Lisle, J.C., Mo, J.N., Pissulla, Th., and Rother, W.
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QUADRUPOLES , *YRAST states , *DOPPLER effect , *DATA analysis , *GROUND state (Quantum mechanics) - Abstract
The lifetimes of eight lower spin levels of the yrast band in 168 Yb, populated via the 154 Sm( 18 O,4n) and 124 Sn( 48 Ca,4n) reactions, were measured, six of them for the first time, by means of the recoil-distance Doppler-shift method. Two versions of the differential decay-curve method have been applied for the data analysis resulting in a very good agreement. The reduced transition probabilities indicate some reduction of the collectivity for states just above the 6 1 + level, i.e. well below the band-crossing. The reasons of this effect are discussed in terms of an interaction between the ground-state band and yet unknown part of the two-quasiparticle ( ν 13 / 2 ) spin-aligned S-band by invoking the shell-structure or alternatively/additionally, as changes in the internal structure/shape induced by the rotation. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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18. Experimental observation of the M1 scissors mode in 254No.
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Bello Garrote, F.L., Lopez-Martens, A., Larsen, A.C., Deloncle, I., Péru, S., Zeiser, F., Greenlees, P.T., Kheswa, B.V., Auranen, K., Bleuel, D.L., Cox, D.M., Crespo Campo, L., Giacoppo, F., Görgen, A., Grahn, T., Guttormsen, M., Hagen, T.W., Harkness-Brennan, L., Hauschild, K., and Henning, G.
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LINEAR polarization , *MOMENTS of inertia , *NUCLEOSYNTHESIS - Abstract
We present the first experimental evidence of the scissors mode in the superheavy nucleus 254No produced in the 208Pb(48Ca, 2 n γ))254No reaction. The spectrum of γ rays emitted by the excited 254No nuclei shows an enhanced γ -ray yield for transition energies of ≈2.5 MeV. By measuring the linear polarization properties of the emitted γ rays, we confirm that the transitions in the enhancement region are predominantly of magnetic-dipole character, characteristic for the scissors mode. To further characterize the enhanced γ -ray yield, simulations of the electromagnetic decay of 254No were performed. The observed enhancement is reproduced by including an M 1 component in the γ strength function with total strength B (M 1 ↑) = 11.8 (19) μ N 2. This is in good agreement with the integrated M 1 strength from sum-rule estimates and new calculations within the quasi-particle random-phase approximation presented here. Our results provide a stringent test of phenomenological formulae for the scissors mode currently used in stellar nucleosynthesis calculations. We find that those formulae are not satisfactory, and we recommend using sum-rule estimates assuming a rigid-body moment of inertia instead for describing the scissors mode in superheavy nuclei. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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19. γ-ray spectroscopy of fission fragments from the cold-neutron 235U induced fission with EXILL.
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Konstantinopoulos, T., Astier, A., Petrache, C., Abudra, A., Bontemps, R., Deloncle, I., Kaim, S., Leguillon, R., Porquet, M.-G., Zerrouki, T., Grente, L., Salsac, M.-D., Zielinska, M., de France, G., Janas, Z., Karny, M., Korgul, A., Ramdhane, M., Gey, G., and Simpson, G.
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COLD neutrons , *ULTRACOLD neutrons , *NEUTRON beams , *NUCLEAR reactors , *SPECTRUM analysis - Abstract
A cold neutron induced fission experiment recently took place at the Institute Laue-Langevin (ILL) in Grenoble. The neutron beam was provided by the nuclear reactor facility at ILL and the detector setup that was used for the γ-spectroscopy of the fission products consisted mainly of the detectors of the EXOGAM array [1], thereby the name of the campaign is EXILL. The main purpose of our measurement was to investigate the nuclei in the region with N = 50 close to 78Ni as well as the nuclei close to the N = 82 shell closure. In this paper, the motivation of the experiment is described as well as the experimental setup and the status of the ongoing data analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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20. High-spin spectroscopy of 139Ce.
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Kaim, S., Petrache, C. M., Gargano, A., Itaco, N., Zerrouki, T., Leguillon, R., Astier, A., Deloncle, I., Konstantinopoulos, T., Régis, J. M., Wilmsen, D., Melon, B., Nannini, A., Ducoin, C., Guinet, D., and Bhattacharjee, T.
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CERIUM isotopes , *SPECTROMETRY , *ANGULAR momentum (Nuclear physics) , *NUCLEAR shell theory , *ENERGY bands , *ANISOTROPY - Abstract
High-spin states in 139Ce have been populated using the 130Te(14C,5n) reaction. The level scheme has been extended to higher spins, including a new band of dipole transitions. The parity of several states has been changed from negative to positive, mainly based on the comparison with the level structure of the core nucleus 140Ce and the results of a realistic shell-model calculation. The dipole band is interpreted as a magnetic rotation band with πh11/2² ⊗ νh-111/2 configuration built on small deformation axial shape with (ɛ2 = 0.12,γ = 0°). [ABSTRACT FROM AUTHOR]
- Published
- 2015
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21. High-spin states in the neutron-rich N = 50 region: nuclear structure close to 78Ni.
- Author
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Astier, A., Porquet, M.-G., Venkova, Ts., Prévost, A., Deloncle, I., Azaiez, F., Buta, A., Curien, D., Dorvaux, O., Duchêne, G., Gall, B. J. P., Khalfallah, F., Piqueras, I., Rousseau, M., Meyer, M., Redon, N., Stézowski, O., Lucas, R., and Bogachev, A.
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NEUTRONS , *NUCLEAR physics , *PARTICLES (Nuclear physics) , *NUCLEAR energy , *PROTONS - Abstract
The spectroscopy of fission fragments, obtained by the 18O+208Pb fusion-fission reaction at 85 MeV bombarding energy, has been performed with the Euroball IV γ-array. High-spin states in many neutron-rich Se, Br, Kr and Rb of the 78Ni region nuclei have been identified for the first time. Several physical aspects which govern the nuclear structure in this mass region are underlined thanks to the new results. Among those, empirical values of the residual proton-neutron interactions have been extracted for the πf5/2xvd5/2 and πp3/2xvd5/2 configurations. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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22. High-Spin States of 84,85Br: Mapping the Proton Sub-Shells towards 78Ni.
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Astier, A., Porquet, M.-G., Venkova, Ts., Deloncle, I., Azaiez, F., Buta, A., Curien, D., Dorvaux, O., Ducheêne, G., Gall, B. J. P., Khalfallah, F., Piqueras, I., Rousseau, M., Meyer, M., Redon, N., Stézowski, O., Lucas, R., and Bogachev, A.
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STATISTICAL correlation , *CONTROLLED fusion , *NUCLEAR reactions , *LINEAR free energy relationship , *PHYSICAL & theoretical chemistry - Abstract
The 84,85Br nuclei have been produced as fission fragments in the fusion reaction 18O+208Pb at 85 MeV bombarding energy and studied with the Euroball IV array. The high-spin states of the odd-odd 84Br nucleus have been identified for the first time. From angular correlation analysis, spin values have been assigned to most of the 85Br excited states up to 4 MeV. All observed states in 84,85Br can be described by various proton excitations involving at least the two sub-shells (πf5/2 and πp3/2) located just above the Z = 28 shell closure. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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23. Magnetic Rotation In 196Pb.
- Author
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Hübel, H., Singh, A. K., Nenoff, N., Roßbach, D., Görgen, A., Chmel, S., Azaiez, F., Astier, A., Bazzacco, D., Belleguic, M., Bouneau, S., Bourgeois, C., Buforn, N., Cederwall, B., Deloncle, I., Domscheit, J., Hannachi, F., Hauschild, K., and Korichi, A.
- Subjects
- *
LEAD , *MOLECULAR rotation , *NUCLEAR excitation - Abstract
A detailed spectroscopic study of high-spin states in [sup 196]Pb has been carried out using the EUROBALL spectrometer array. Five new magnetic-rotational bands have been found and the previously known bands have been extended. With one exception, all the bands have been connected to lower-lying states and excitation energies, spins and parities have been determined. Doppler-broadend lineshapes have been analyzed and lifetimes of states in four of the bands have been determined. The B(M1) values show the decrease with increasing spin that is expected for shears bands. Configurations of proton-particle excitations coupled to neutron-hole states have been assigned to the bands. [ABSTRACT FROM AUTHOR]
- Published
- 2003
24. Nucleosynthesis of 26Al in massive stars: New 27Al states above α and neutron emission thresholds.
- Author
-
Benamara, S., de Séréville, N., Laird, A. M., Hammache, F., Stefan, I., Roussel, P., Ancelin, S., Assié, M., Coc, A., Deloncle, I., Fox, S. P., Kiener, J., Lefebvre, L., Lefebvre-Schuhl, A., Mavilla, G., Morfouace, P., Sánchez-Bcnítez, Á. M., Perrot, L., Sinha, M., and Tatischeff, V.
- Subjects
- *
NUCLEOSYNTHESIS , *SUPERGIANT stars , *NEUTRON emission , *RADIOISOTOPES , *NUCLEAR reactions - Abstract
The 26Al radioisotope is of great importance for understanding the chemical and dynamical evolution of our galaxy. Among the possible stellar sources, massive stars are believed to be the main producer of this radioisotope. Understanding 26Al nucleosynthesis in massive stars requires estimates of the thermonuclear reaction rates of the 26Al(n,p)26Mg, 26Al(n,α)23Na, and 23Na(α,p)26Mg reactions. These reaction rates depend on the spectroscopic properties of 27Al states above the neutron and alpha thresholds. In this context, the 27Al(p,p)27Al* reaction was studied at 18 MeV using a high-resolution Enge Split-Pole spectrometer. States from the ground state up to excitation energies of ≈14 MeV were populated. While up to the 23Na + α threshold no additional states are observed, we report for the first time 30 new levels above the 23Na + α threshold and more than 30 new states above the 26Al + n threshold for which excitation energies are determined with an uncertainty of 4-5 keV. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
25. High-spin level structure of 35S.
- Author
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Aydin, S., Ionescu-Bujor, M., Recchia, F., Lenzi, S. M., Bouhelal, M., Bazzacco, D., Bizzeti, P. G., Bizzeti-Sona, A. M., de Angelis, G., Deloncle, I., Farnea, E., Gadea, A., Gottardo, A., Haas, F., Huyuk, T., Laftchiev, H., Lunardi, S., Mengoni, D., Menegazzo, R., and Michelagnoli, C.
- Subjects
- *
HIGH spin physics , *PARTICLES (Nuclear physics) , *NUCLEAR excitation , *NUCLEAR structure , *SULFUR isotopes , *EVAPORATION (Chemistry) , *GAMMA ray spectroscopy - Abstract
The nucleus 35S has been studied by in-beam γ-ray spectroscopy using the 24Mg(14N,3p) fusion-evaporation reaction at Elab = 40 MeV. A level scheme extended up to Jπ = 17/2+ at 8023 keV and Jπ = 13/2- at 6352 keV has been established. Lifetimes of six excited states have been determined by applying the Doppler shift attenuation method. The experimental data have been compared with the results of large-scale shell model calculations performed using different effective interactions and model spaces allowing particle-hole excitations across the N = Z = 20 shell gap. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
26. High-spin structures of 3688Kr52 and 3789Rb52: Evolution from collective to single-particle behavior.
- Author
-
Astier, A., Porquet, M.-G., Venkova, Ts., Duchêne, G., Azaiez, F., Curien, D., Deloncle, I., Dorvaux, O., Gall, B. J. P., Redon, N., Rousseau, M., and Stézowski, O.
- Subjects
- *
NEUTRON-proton interactions , *HIGH spin physics , *NEUTRONS , *HYBRID reactors , *NUCLEAR reactions , *RADIOACTIVE decay , *PARTICLES (Nuclear physics) , *ANGULAR correlations (Nuclear physics) - Abstract
The high-spin states of the two neutron-rich nuclei 88Kr52 and 89Rb52 have been studied from the 18O+208Pb fusion-fission reaction. Their level schemes were built from triple β-ray coincidence data, and β-β angular correlations were analyzed in order to assign spin and parity values to most of the observed states. The two level schemes evolve from collective structures to single-particle excitations as a function of the excitation energy. Comparison with results of shell-model calculations gives the specific proton and neutron configurations which are involved to generate the angular momentum alongthe yrast lines. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
27. High-spin structures of 13655Cs81.
- Author
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Astier, A., Porquet, M.-G., Duchêne, G., Azaiez, F., Curien, D., Deloncle, I., Dorvaux, O., Gall, B. J. P., Houry, M., Lucas, R., Srivastava, P. C., Redon, N., Rousseau, M., Stézowski, O., and Theisen, Ch.
- Subjects
- *
NUCLEAR spin , *NUCLEAR structure , *CESIUM isotopes , *NUCLEAR fusion , *NUCLEAR reactions , *COINCIDENCE , *NUCLEAR excitation , *NUCLEAR shell theory - Abstract
Odd-odd 136Cs nuclei have been produced in the 18O + 208Pb and 12C + 238U fusion-fission reactions and their γ rays studied with the Euroball array. The high-spin level scheme was built up to ~4.7 MeV excitation energy and spin I ~ 16h from the triple γ-ray coincidence data. The configurations of the three structures observed above ~2 MeV excitation energy are first discussed bγ analogy with the proton excitations identified in the semimagic 137Cs82 nucleus, which involve the three high-j orbits lying above the Z = 50 gap, πg7/2, πd5/2, and πhn1/2- This is confirmed by the results of shell-model calculations performed in this work. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
28. Plunger lifetimes and electromagnetic transition strengths in odd 167Yb.
- Author
-
Gladnishki, K.A., Petkov, P., Dewald, A., Möller, O., Deloncle, I., Tonev, D., Reese, M., Fransen, C., Hackstein, M., Jolie, J., Pissulla, Th., Rother, W., and Zell, K.O.
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- *
ELECTROMAGNETIC devices , *TRANSITION strengths , *DOPPLER effect , *NUMERICAL calculations , *NUCLEAR spin ,YTTERBIUM isotopes - Abstract
Abstract: Nine lifetimes have been determined for the first time in the and bands of 167Yb by means of Recoil distance Doppler-shift measurements carried out at the Cologne FN tandem. For the data analysis, a dedicated version of the Differential decay curve method was used. The newly deduced transition strengths and the level scheme are reasonably described by the Particle plus triaxial rotor model (PTRM) calculations except for the behavior of the quadrupole collectivity in the two signatures of the band. The stretched B(E2)ʼs in the favored signature are appreciably larger than those in the unfavored signature. The effect increases with spin. In the PTRM calculations, the wave functions of the favored signature levels contain larger contribution of low-Ω orbitals from parentage than those of the unfavored levels. This could selectively increase the deformation of the favored signature band members. If so, rotation and Coriolis interaction would give rise to a dynamic shape coexistence taking place between the two signatures. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
29. High-spin structure and intruder excitations in 36C1.
- Author
-
Aydin, S., Recchia, F., Ionescu-Bujor, M., Gadea, A., Lenzi, S. M., Lunardi, S., Ur, C. A., Bazzacco, D., Bizzeti, P. G., Bizzeti-Sona, A. M., Bouhelal, M., de Angelis, G., Deloncle, I., Farnea, E., Gottardo, A., Haas, F., Huyuk, T., Laftchiev, H., Mengoni, D., and Menegazzo, R.
- Subjects
- *
NUCLEAR spin , *NUCLEAR structure , *NUCLEAR excitation , *NUCLEAR fusion , *NUCLEAR reactions , *DOPPLER effect , *PHYSICS experiments - Abstract
Excited states up to Jπ = 11- at 10 296 keV and Jπ = 10+ at 10 707 keV have been populated in the odd-odd 36C1 nucleus using the 24Mg(14N,2p) fusion-evaporation reaction at Elab = 31 MeV. Twenty new states and 62 new γ transitions have been identified by employing γ-γ and γ-γ-γ coincidences. Lifetimes have been investigated by the Doppler shift attenuation method. The experimental data have been compared with the results of large-scale shell-model calculations performed using different effective interactions and model spaces allowing particle-hole excitations across the N = Z = 20 shell gap. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
30. High-spin structures of five N = 82 isotopes: 13654Xe, 13755Cs, 13856Ba, 13957La, and 14058Ce.
- Author
-
Astier, A., Porquet, M.-G., Venkova, Ts., Verney, D., Theisen, Ch., Duchêne, G., Azaiez, F., Barreau, G., Curien, D., Deloncle, I., Dorvaux, O., Gall, B. J. P., Houry, M., Lucas, R., Redon, N., Rousseau, M., and Stézowski, O.
- Subjects
- *
NUCLEAR spin , *NUCLEAR structure , *RADIOISOTOPES , *ANGULAR correlations (Nuclear physics) , *NUCLEAR energy , *NUCLEAR excitation - Abstract
Five N = 82 isotones have been produced in two fusion-fission reactions and their &ggr; rays studied with the Euroball array. The high-spin states of 139La have been identified, while the high-spin yrast and near-to-yrast structures of the four others have been greatly extended. From angular correlation analysis, spin values have been assigned to some states of 136Xe and 137Cs. Several cascades involving &ggr; rays of 139La have been found to be delayed; they deexcite an isomeric state with T1/2 = 315(35) ns located at 1800 keV excitation energy. The excited states of these five N = 82 isotones are expected to be due to various proton excitations involving the three high-j subshells located above the Z = 50 shell closure. This is confirmed by the results of shell-model calculations performed in this work. In addition, high-spin states corresponding to the excitation of the neutron core have been unambiguously identified in 136Xe, 137Cs, and 138Ba. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
31. High-spin states with seniority v = 4,5, and 6 in119-126Sn.
- Author
-
Astier, A., Porquet, M.-G., Theisen, Ch., Verney, D., Deloncle, I., Houry, M., Lucas, R., Azaiez, F., Barreau, G., Curien, D., Dorvaux, O., Duchêne, G., P. Gall, B. J., Redon, N., Rousseau, M., and Stézowski, O.
- Subjects
- *
NUCLEAR spin , *TIN isotopes , *NUCLEAR fragmentation , *NUCLEAR fission , *ENERGY levels (Quantum mechanics) , *NUCLEAR isomers , *NUCLEAR excitation - Abstract
The 119_126Sn nuclei have been produced as fission fragments in two reactions induced by heavy ions: 12C + 238U at a bombarding energy of 90 MeV and 18O + 208Pb at 85 MeV. Their level schemes have been built from γ rays detected using the Euroball array. High-spin states located above the long-lived isomeric states of the evenand odd-A 120-126Sn nuclei have been identified. Moreover, isomeric states lying around 4.5 MeV have been established in 120,122,124,126Sn from delayed coincidences between the fission fragment detector SAPhIR and the Euroball array. The states located above 3 MeV excitation energy are ascribed to several broken pairs of neutrons occupying the vh11/2 orbit. The maximum value of angular momentum available in such a high-j shell, i.e., for midoccupation and the breaking of the three neutron pairs, has been identified. This process is observed for the first time in spherical nuclei. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
32. Medium-spin states in neutron-rich 83As and 81As.
- Author
-
Porquet, M.-G., Astier, A., Verney, D., Venkova, Ts., Deloncle, I., Azaiez, F., Buta, A., Curien, D., Dorvaux, O., Duchêne, G., Gall, B. J. P., Khalfallah, F., Piqueras, I., Rousseau, M., Meyer, M., Redon, N., Stézowski, O., and Bogachev, A.
- Subjects
- *
NEUTRONS , *FISSION cross sections , *NUCLEAR fission , *NUCLEAR cross sections , *NUCLEAR excitation - Abstract
The 83, 81As nuclei have been produced as fission fragments in the fusion reaction 18O + 208Pb at 85 MeV bombarding energy and studied with the Euroball array. Medium-spin states of 83, 81As have been established up to ~3.5 MeV excitation energy. From angular correlation analysis, spin values have been assigned to most of the 81As excited states. The behaviors of the yrast structures identified in this work are discussed in comparison with the general features known in the mass région. Then they are compared to the results of two theoretical approaches: the "rotor + quasiparticle" for 81As and the shell model using the effective interactions JUN45 for 83, 81Ks. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
33. Measurements of nuclear γ-ray line emission in interactions of protons and a particles with N, O, Ne, and Si.
- Author
-
Benhabiles-Mezhoud, H., Kiener, J., Thibaud, J.-P., Tatischeff, V., Deloncle, I., Coc, A., Duprat, J., Hamadache, C., Lefebvre-Schuhl, A., Dalouzy, J.-C., de Grancey, F., de Oliveira, F., Dayras, F., de Séréville, N., Pellegriti, M.-G., Lamia, L., and Ouichaoui, S.
- Subjects
- *
PARTICLES (Nuclear physics) , *PROTONS , *ISOTOPES , *SPIN excitations , *NEUTRON-proton interactions , *NUCLEAR reactions - Abstract
γ-ray production cross sections have been measured in proton irradiations of N, Ne, and Si and α-particle irradiations of N and Ne. In the same experiment we extracted also line shapes for strong γ-ray lines of 16O produced in proton and α-particle irradiations of O. For the measurements gas targets were used for N, O, and Ne and a thick foil for Si. All targets were of natural isotopic composition. Beams in the energy range up to 26 MeV for protons and 39 MeV for α particles were delivered by the Institut de Physique Nucléaire-Orsay tandem accelerator. The γ rays were detected with four high-purity Ge detectors in the angular range 30° to 135°. We extracted 36 cross-section excitation functions for proton reactions and 14 for α-particle reactions. For the majority of the excitation functions no other data exist to our knowledge. Where comparison with existing data was possible, usually a very good agreement was found. It is shown that these data are very interesting for constraining nuclear reaction models. In particular, the agreement of cross section calculations in the nuclear reaction code talys with the measured data could be improved by adjusting the coupling schemes of collective levels in the target nuclei 14N, 20,22Ne, and 28Si. The importance of these results for the modeling of nuclear γ-ray line emission in astrophysical sites is discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
34. High-spin excitations of the odd-odd 88 37Rb51 and 86 35Br51 nuclei: $ \pi$p3/2 $ \nu$d5/2 and $ \pi$f5/2 $ \nu$d5/2 residual interactions.
- Author
-
Porquet, M.-G, Astier, A., Venkova, Ts., Deloncle, I., Azaiez, F., Buta, A., Curien, D., Dorvaux, O., Duchêne, G., Gall, B. J. P., Khalfallah, F., Piqueras, I., Rousseau, M., Meyer, M., Redon, N., Stézowski, O., Lucas, R., and Bogachev, A.
- Subjects
- *
NUCLEAR excitation , *PARTICLES (Nuclear physics) , *ANGULAR correlations (Nuclear physics) , *GAMMA rays , *FERMI surfaces , *NUCLEAR research - Abstract
The odd-odd 88 37Rb51 and 86 35Br51 nuclei have been produced as fission fragments in the fusion reaction 18O$ + $208Pb at 85MeV bombarding energy and studied with the Euroball IV array. Their high-spin level schemes have been built from the triple $ \gamma$ -ray coincidence data and $ \gamma$ - $ \gamma$ angular correlations have been analyzed in order to assign spin and parity values to many observed states. The proposed configurations involve proton excitations from three sub-shells located close to the Fermi levels, $ \pi$ p3/2 , $ \pi$ f5/2 , and $ \pi$ g9/2 , the $ \nu$ d5/2 neutron acting as a spectator. The residual $ \pi$ $ \nu$ interactions are extracted from the multiplets of states resulting from the $ \pi$ p3/2 $ \nu$ d5/2 and $ \pi$ f5/2 $ \nu$ d5/2 configurations. The empirical values of the latter are discussed and compared to those known in two similar configurations having jp = jn with lp = ln + 1 , where the role of the tensor force had been highlighted. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
35. High-spin excitations of 81, 82, 83, 85Se : Competing single-particle and collective structures around N = 50.
- Author
-
Porquet, M., Astier, A., Venkova, Ts., Prévost, A., Deloncle, I., Azaiez, F., Buta, A., Curien, D., Dorvaux, O., Duchêne, G., Gall, B., Khalfallah, F., Piqueras, I., Rousseau, M., Meyer, M., Redon, N., Stézowski, O., Lucas, R., and Bogachev, A.
- Subjects
- *
NUCLEAR physics , *CONTROLLED fusion , *SPIN excitations , *NUCLEAR reactions , *PROTON scattering , *NUCLEAR excitation - Abstract
The 81, 82, 83, 85Se nuclei have been produced as fission fragments in the fusion reaction 18O + 208Pb at 85MeV bombarding energy and studied with the Euroball IV array. Their high-spin level schemes have been built from the triple $ \gamma$ -ray coincidence data and $ \gamma$ - $ \gamma$ angular correlations have been analyzed in order to assign spin and parity values to many observed states. The lowest-spin states of the two-neutron and three-neutron configurations are strongly mixed with two-proton excitations among the fp orbits. On the other hand, the highest-spin states of these neutron configurations are found to remain almost pure. Neutron excitation across the N = 50 gap is observed both in 83Se49 and in 85Se51 . [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
36. Fission fragment properties obtained in the γ - γ - γ coincidence method in the reaction 208Pb(18O, f ).
- Author
-
Bogachev, A., Krupa, L., Dorvaux, O., Kozulin, E., Itkis, M., Porquet, M.-G., Astier, A., Curien, D., Deloncle, I., Duchene, G., Gall, B. J. P., Hanappe, F., Khalfallah, F., Rousseau, M., Stuttge, L., Redon, N., and Stezowski, O.
- Subjects
- *
NUCLEAR fission , *NEUTRON beams , *NEUTRON multiplicity , *NUCLEAR physics , *NUCLEAR reactions - Abstract
Independent fission fragment yields have been obtained for the six fragment pairs ( Z L/ Z H = 44/46 , 42/48, 40/50, 38/52, 36/54 and 34/56) in 208Pb(18O, f ) at the beam energy E = 85 MeV. γ -ray spectroscopy technique was applied to analyze the experimental data. With use of these data the mass distribution of fission fragments was restored. Data on average fragment spin distribution and total neutron multiplicity are presented. The agreement of the obtained results with other experimental data proves the validity of the applied method to solve this kind of problems. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
37. High-spin excitations of 84 35Br49 and 85 35Br50: Mapping the proton sub-shells towards 78Ni.
- Author
-
Astier, A., Porquet, M., Venkova, Ts., Deloncle, I., Azaiez, F., Buta, A., Curien, D., Dorvaux, O., Duchêne, G., Gall, B., Khalfallah, F., Piqueras, I., Rousseau, M., Meyer, M., Redon, N., Stézowski, O., Lucas, R., and Bogachev, A.
- Subjects
- *
NUCLEAR reactions , *NUCLEAR fission , *CONTROLLED fusion , *SPIN excitations , *FORCE & energy - Abstract
The 84, 85Br nuclei have been produced as fission fragments in the fusion reaction 18O + 208Pb at 85MeV bombarding energy and studied with the Euroball IV array. The high-spin states of the odd-odd 84Br nucleus have been identified for the first time, the observed structure being built on the known 6- isomeric state. High-spin states of 85Br have been observed up to 5.4MeV excitation energy and spin I ∼ 21/2. From angular correlation analysis, spin values have been assigned to most of the 85Br excited states up to 4MeV. None of these excited states has been found to exhibit a delayed decay having T 1/2 > 10ns. All the observed states in 84, 85Br can be described by various proton excitations involving at least the two sub-shells ( π f 5/2 and π p 3/2) located just above the Z = 28 shell closure. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
38. Beyond the N = 50 shell closure: High-spin excitations of 87Kr and ground-state spin of 87Br.
- Author
-
Porquet, M., Venkova, Ts., Astier, A., Deloncle, I., Prévost, A., Azaiez, F., Buta, A., Curien, D., Dorvaux, O., Duchêne, G., Gall, B., Khalfallah, F., Piqueras, I., Rousseau, M., Meyer, M., Redon, N., Stézowski, O., Lucas, R., and Bogachev, A.
- Subjects
- *
NUCLEAR shell theory , *NUCLEAR fission , *KRYPTON isotopes , *NUCLEAR physics , *FISSION gases - Abstract
The 87Kr nucleus has been produced as fission fragment in the fusion reaction 18O + 208Pb at 85MeV bombarding energy and studied with the Euroball IV array. High-spin states of this neutron-rich isotope have been identified for the first time. Its level scheme has been obtained up to 6.3MeV excitation energy and spin I ∼ 23/2ℏ. Its structure is interpreted by analogy with those of the heavier isotones. The proposed configurations involve both proton and neutron excitations from several sub-shells located close to the Fermi levels, particularly ν d 5/2, π p 3/2 f 5/2 and π g 9/2. Moreover, a revised spin value of 5/2- for the 87Br ground state is proposed. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
39. New high-spin states of 147Nd and 145Ce: Octupole correlation in the N = 87 isotones.
- Author
-
Venkova, Ts., Porquet, M. -G., Astier, A., Deloncle, I., Petkov, P., Prévost, A., Azaiez, F., Bogachev, A., Buta, A., Curien, D., Dorvaux, O., Duchêne, G., Durell, J., Gall, B., Houry, M., Khalfallah, F., Lucas, R., Meyer, M., Piqueras, I., and Redon, N.
- Subjects
- *
NUCLEAR fission , *NUCLEAR reactions , *NUCLEAR energy , *RADIATION , *NUCLEAR size (Physics) , *NUCLEAR spectroscopy , *SPIN excitations , *NEUTRONS - Abstract
High-spin states of the N = 87 nuclei, 147Nd and 145Ce, have been populated in the 12C + 238U and 18O + 208Pb fusion-fission reactions at 90 MeV and 85 MeV bombarding energy, respectively. The emitted γ-radiation was detected using the Euroball III and IV arrays. High-spin states of the 147Nd isotope have been identified for the first time. The high-spin yrast and near-to-yrast structures of the 145Ce nucleus have been considerably extended. The newly observed structures, discussed by analogy with the neighbouring isotones, show the coupling of an h 9/2 neutron to the quadrupole and octupole excitations of the core. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
40. High-spin structures of51121, 123, 125, 127Sb nuclei: Single proton and core-coupled states.
- Author
-
Porquet, M.G., Venkova, Ts., Lucas, R., Astier, A., Bauchet, A., Deloncle, I., Prévost, A., Azaiez, F., Barreau, G., Bogachev, A., Buforn, N., Buta, A., Curien, D., Doan, T. P., Donadille, L., Dorvaux, O., Duchêne, G., Durell, J., Ethvignot, Th., and Gall, B.P.J.
- Subjects
- *
INTERMEDIATES (Chemistry) , *SOLUTION (Chemistry) , *ELECTROMAGNETIC waves , *GAMMA rays , *ENGINEERING instruments , *PARTICLES (Nuclear physics) - Abstract
The121,123,125,127Sb nuclei have been produced as fission fragments in three reactions induced by heavy ions:12C +238U at 90 MeV bombarding energy,18O +208Pb at 85 MeV, and31P +176Yb at 152 MeV. Their level schemes have been built from gamma rays detected using the EUROBALL III and IV arrays. High-spin states of123,125,127Sb nuclei have been identified for the first time. Moreover isomeric states lying around 2.3 MeV have been established in123,125,127Sb from the delayed coincidences between the fission fragment detector SAPhIR and the gamma array. All the observed states can be described by coupling ad5/2 org7/2 proton to an excited Sn core involving either vibrational states or broken neutron pairs. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
41. Medium-spin excitations of the neutron-rich84Se isotope: Possible decrease in energy of the N = 50 neutron-core excitation.
- Author
-
A. Prévost, Porquet, M. G., Astier, A., Deloncle, I., Azaiez, F., Buta, A., Curien, D., Dorvaux, O., Duchêne, G., Gall, B. J. P., Khalfallah, F., Piqueras, I., Rousseau, M., Meyer, M., Redon, N., Stézowski, O., Venkova, Ts., Lucas, R., and Bogachev, A.
- Subjects
- *
NUCLEAR shell theory , *PARTICLES (Nuclear physics) , *NEUTRONS , *SPIN excitations , *NUCLEAR excitation , *NUCLEAR physics - Abstract
The84Se nucleus has been produced as fission fragment in the fusion reaction18O +208Pb at 85MeV bombarding energy and studied with the Euroball IV array. Medium-spin states of this neutron-rich isotope have been identified for the first time. Its level scheme has been obtained up to 4.9MeV excitation energy and spinI~ 7?. Its structure is interpreted by analogy with those of the stable heavier isotones. The evolution of the energy of theN= 50 neutron-core excitation is discussed as a function of the proton number. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
42. New determinations of gamma-ray line intensities of the Ep=550 and 1747keV resonances of the 13C(p,γ)14N reaction.
- Author
-
Kiener, J., Gros, M., Tatischeff, V., Attié, D., Bailly, I., Bauchet, A., Chapuis, C., Cordier, B., Deloncle, I., Porquet, M. G., Schanne, S., de Séréville, N., and Tauzin, G.
- Subjects
- *
NUCLEAR reactions , *GAMMA rays , *RESONANCE , *PROTON beams - Abstract
Gamma-ray angular distributions for the resonances at Ep=550 and 1747 keV of the radiative capture reaction 13C(p,γ)14N have been measured, using intense proton beams on isotopically pure 13C targets. Experimental gamma-ray spectra were obtained with three HP–Germanium detectors at four angles for Ep=550 keV and six angles for Ep=1747 keV in the range of 0–90° with respect to the proton beam. From the data, relative intensities for the strongest transitions were extracted with an accuracy of typically 5%, making these resonances new useful gamma-ray standards for efficiency calibration in the energy range from Eγ=1.6–9 MeV. Gamma-ray branching ratios were obtained for several levels of 14N and are compared with literature values. [Copyright &y& Elsevier]
- Published
- 2004
- Full Text
- View/download PDF
43. Two-quasiparticle and collective excitations in transitional 108,110Pd nuclei.
- Author
-
Lalkovski, S., Minkova, A., Porquet, M.-G., Bauchet, A., Deloncle, I., Astier, A., Buforn, N., Donadille, L., Dorvaux, O., Gall, B. P. J., Lucas, R., Meyer, M., Prévost, A., Redon, N., Schulz, N., and Stézowski, O.
- Subjects
- *
QUASIPARTICLES , *NUCLEAR excitation , *ISOTOPES , *SPECTRUM analysis , *HEAVY ions , *NUCLEAR fission - Abstract
High-spin states in 108,110Pd isotopes are studied by γ-ray spectroscopy of heavy-ion-induced fission. The Pd isotopes are produced in the fission channel of the 31P + 176Yb reaction at beam energy 152 MeV. The prompt γ-rays are detected with the EUROBALL4 multidetector array. The yrast states of 108,110Pd have been observed above the region of the first backbend. The level scheme of 108Pd was extended with a new negative-parity band. The yrast sequence in 110Pd is observed up to spin I = 14+ and negative-parity bands have also been identified. The back bending in these even-mass Pd isotopes is associated with the alignment of the neutron (h11/2)² pair. The negative-parity states arise from two neutron configurations vh11/2 ⊗ vg7/2 and vh11/2 ⊗ vd5/2 and they are interpreted in the frame of two-quasiparticle + rotor model as semidecoupled bands. The observed experimental staggering in the γ-bands of 108,110Pd supports the theoretical predictions for γ-instability of their shapes. [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
44. Evolution of the ... configuration in the neutron-rich ... and ... isotopes.
- Author
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Porquet, M.-G., Venkova, Ts., Astier, A., Bauchet, A., Deloncle, I., Buforn, N., Donadille, L., Dorvaux, O., Gall, B. J. P., Lalkovski, S., R. Lucas, Meyer, M., Minkova, A., Prévost, A., Redon, N., Schulz, N., and Stézowski, O.
- Subjects
- *
PARTICLES (Nuclear physics) , *NUCLEAR physics , *NUCLEAR fission , *NUCLEAR reactions ,RHODIUM isotopes ,SILVER isotopes - Abstract
The 110,112 Rh and 114',16Ag nuclei have been produced as fission fragments in the fusion reaction 18 + 208Pb at 85 MeV. Their level schemes have been built from gamma-rays detected using the Euroball IV array. High-spin states of these neutron-rich nuclei have been identified for the first time. The yrast structures consist of rotational bands in which the odd proton occupies the πg9/2 sub-shell and the odd neutron the vh11/2 sub-shell. The evolution of the πg9/2 ® vh11/2 band structure is analyzed as a function of the neutron number. [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
45. Detailed study of magnetic rotation in 196Pb.
- Author
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Singh, A. K., Nenoff, N., Roßbach, D., Görgen, A., Chmel, S., Azaiez, F., Astier, A., Bazzacco, D., Belleguic, M., Bouneau, S., Bourgeois, C., Buforn, N., Cederwall, B., Deloncle, I., Domscheit, J., Hannachi, F., Hauschild, K., Hübel, H., Korichi, A., and Korten, W.
- Subjects
- *
HIGH spin physics , *NUCLEAR reactions - Abstract
High-spin states in 196Pb have been populated in two different heavy-ion-induced reactions using thin and Au-backed targets, respectively. Gamma-ray coincidences were measured using the EUROBALL spectrometer array. Five new magnetic-rotational bands have been found. The previously known four bands have been extended and some of their levels have been reordered. With one exception, all the bands have been connected to lower-lying states and excitation energies, spins and parities have been determined. From the systematic properties of the bands and from comparison to tilted-axis cranking calculations, arguments for configuration assignments to the bands are derived. It is suggested that the bands are based on proton 11− and 8+ particle states coupled to various neutron–hole excitations. [Copyright &y& Elsevier]
- Published
- 2002
- Full Text
- View/download PDF
46. New excited 2+ and 3- two-proton states in 84210Po126 populated by two-proton transfer.
- Author
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Dupont, E., Astier, A., Petrache, C. M., Lv, B. F., Deloncle, I., Kiener, J., Orlandi, R., Makii, H., Nishio, K., Hirose, K., Asai, M., Sato, T. K., Tsukada, K., Ito, Y., Kean, K. R., Yanagihara, R., and Scamps, G.
- Subjects
- *
TELESCOPES , *COULOMB barriers (Nuclear fusion) - Abstract
Five new 2+ levels have been established in the semimagic 210Po nucleus from a 208Pb(12C,10Be) two-proton transfer experiment, performed at energies close to the Coulomb barrier at JAEA Tokai. A setup combining Ge, LaBr3, and Si telescopes was used to detect both in-beam γ rays and ejectile residues. The new 2+ states have been established by means of the transitions toward the 0+ ground state which are present in the γ spectra produced by properly selecting the excitation energy in 210Po after kinematical reconstruction. (f7/2)², h9/2⊗f5/2, (i13/2)², f7/2⊗p3/2, and f7/2⊗f5/2 two-proton configurations are assigned to these states. In addition, a new 3-level has also been established in this nucleus, very likely originating from the f7/2⊗i13/2 configuration. Shell-model calculations strongly support these assignments. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
47. Influence of octupole vibration on the low-lying structure of 251Fm and other heavy N=151 isotones.
- Author
-
Rezynkina, K., Lopez-Martens, A., Hauschild, K., Deloncle, I., Péru, S., Brionnet, P., Chelnokov, M. L., Chepigin, V. I., Dorvaux, O., Déchery, F., Faure, H., Gall, B., Isaev, A. V., Izosimov, I. N., Katrasev, D. E., Kuznetsov, A. N., Kuznetsova, A. A., Malyshev, O. N., Popeko, A. G., and Popov, Y. A.
- Subjects
- *
EXCITED state energies , *ALPHA decay , *ELECTRON spectroscopy - Abstract
The structure of low-lying excited states in 251Fm, populated by the α decay of 255No, has been investigated by means of combined γ and internal conversion electron spectroscopy. The values for the internal conversion coefficients for the 1/2+→5/2+ and 5/2+→9/2- transitions have been measured. The determined M2/E3 mixing ratio and lifetime for the 5/2+ decay to the ground state allowed to determine the corresponding reduced transitions strengths of B(E3)=18(6) W.u. and B(M2)=3.0(6)×10-3 W.u. These results, as well as the results of previous studies in N=151 isotopes, are compared to theoretical calculations beyond the mean-field approach, including the first QRPA calculations using the Gogny D1M parametrization for such heavy odd-N nuclei. The comparison points to the importance of accounting for the octupole vibrations for a proper understanding of the low-lying nuclear structure of some of the heaviest elements. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
48. Gogny-Hartree-Fock-Bogolyubov plus quasiparticle random-phase approximation predictions of the M1 strength function and its impact on radiative neutron capture cross section.
- Author
-
Goriely, S., Hilaire, S., Péru, S., Martini, M., Deloncle, I., and Lechaftois, F.
- Subjects
- *
HARTREE-Fock approximation , *NEUTRON capture , *QUASIPARTICLES - Abstract
Valuable theoretical predictions of nuclear dipole excitations in the whole chart are of great interest for different nuclear applications, including in particular nuclear astrophysics. Here we extend our large-scale calculations of the E1 γ-ray strength function, obtained in the framework of the axially- symmetric-deformed quasiparticle random phase approximation (QRPA) based on the finite-range D1M Gogny force, to the calculation of the M1 strength function. We compare our QRPA prediction of the M1 strength with available experimental data and show that a relatively good agreement is obtained provided the strength is shifted globally by about 2 MeV and increased by an empirical factor of 2. Predictions of the M1 strength function for spherical and deformed nuclei within the valley of ß stability as well as in the neutron-rich region are discussed. Its impact on the radiative neutron capture cross section is also analyzed. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
49. Superdeformed nuclear matter in nuclei with Z ≥ 82 : Magnetic properties and neutron shell gap.
- Author
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Redon, N., Buforn, N., Duffait, R., Lautesse, P., Meyer, M., Pr&eacue;vost, A., Stézowski, O., Astier, A., Bauchet, A., Deloncle, I., Porquet, M. G., Domscheit, J., Goergen, A., Hübel, H., Mergel, E., Neumann, S., Rossbach, D., Nenoff, N., Schoenwasser, G., and Wilson, A. N.
- Subjects
- *
NUCLEAR physics , *PHYSICS , *NEUTRONS , *CONSTITUTION of matter , *PARTICLES (Nuclear physics) , *SPECTROMETERS - 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 Mi character, giving access to the magnetic properties of the v[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. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
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