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1. Cross-shell states in 15C: A test for p-sd interactions

Author: J. Lois-Fuentes, B. Fernández-Domínguez, X. Pereira-López, F. Delaunay, W.N. Catford, A. Matta, N.A. Orr, T. Duguet, T. Otsuka, V. Somà, O. Sorlin, T. Suzuki, N.L. Achouri, M. Assié, S. Bailey, B. Bastin, Y. Blumenfeld, R. Borcea, M. Caamaño, L. Caceres, E. Clément, A. Corsi, N. Curtis, Q. Deshayes, F. Farget, M. Fisichella, G. de France, S. Franchoo, M. Freer, J. Gibelin, A. Gillibert, G.F. Grinyer, F. Hammache, O. Kamalou, A. Knapton, Tz. Kokalova, V. Lapoux, B. Le Crom, S. Leblond, F.M. Marqués, P. Morfouace, J. Pancin, L. Perrot, J. Piot, E. Pollacco, D. Ramos, D. Regueira-Castro, C. Rodríguez-Tajes, T. Roger, F. Rotaru, M. Sénoville, N. de Séréville, R. Smith, M. Stanoiu, I. Stefan, C. Stodel, D. Suzuki, J.C. Thomas, N. Timofeyuk, M. Vandebrouck, J. Walshe, and C. Wheldon
Subjects: One neutron pick-up reaction, Neutron-rich carbon isotopes, Phenomenological shell-model, Ab initio calculations, Physics, QC1-999
Abstract: The low-lying structure of 15C has been investigated via the neutron-removal 16C(d,t) reaction. Along with the known bound neutron sd-shell states, unbound p-shell hole states have been observed. The excitation energies and the deduced spectroscopic factors of the cross-shell states are an important measure of the [(p)−1(sd)2] neutron configurations in 15C. Our results show a very good agreement with shell-model calculations using the SFO-tls interaction for 15C. However, this same interaction predicted energies that were too low for the corresponding hole states in the N=9 isotone 17O and adjustment of the p-sd and sd-sd monopole terms was required to match the 17O energies. In addition, the excitation energies and spectroscopic factors have been compared to the first calculations of 15C with the ab initio self-consistent Green's function method employing the NNLOsat interaction. The results show the sensitivity to the size of the N=8 shell gap and highlight the need to go beyond the current truncation scheme.
Published: 2023
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2. Intruder configurations in 29Ne at the transition into the island of inversion: Detailed structure study of 28Ne

Author: H. Wang, M. Yasuda, Y. Kondo, T. Nakamura, J.A. Tostevin, K. Ogata, T. Otsuka, A. Poves, N. Shimizu, K. Yoshida, N.L. Achouri, H. Al Falou, L. Atar, T. Aumann, H. Baba, K. Boretzky, C. Caesar, D. Calvet, H. Chae, N. Chiga, A. Corsi, H.L. Crawford, F. Delaunay, A. Delbart, Q. Deshayes, Zs. Dombrádi, C. Douma, Z. Elekes, P. Fallon, I. Gašparić, J.-M. Gheller, J. Gibelin, A. Gillibert, M.N. Harakeh, A. Hirayama, C.R. Hoffman, M. Holl, A. Horvat, Á. Horváth, J.W. Hwang, T. Isobe, J. Kahlbow, N. Kalantar-Nayestanaki, S. Kawase, S. Kim, K. Kisamori, T. Kobayashi, D. Körper, S. Koyama, I. Kuti, V. Lapoux, S. Lindberg, F.M. Marqués, S. Masuoka, J. Mayer, K. Miki, T. Murakami, M.A. Najafi, K. Nakano, N. Nakatsuka, T. Nilsson, A. Obertelli, N.A. Orr, H. Otsu, T. Ozaki, V. Panin, S. Paschalis, A. Revel, D. Rossi, A.T. Saito, T. Saito, M. Sasano, H. Sato, Y. Satou, H. Scheit, F. Schindler, P. Schrock, M. Shikata, Y. Shimizu, H. Simon, D. Sohler, O. Sorlin, L. Stuhl, S. Takeuchi, M. Tanaka, M. Thoennessen, H. Törnqvist, Y. Togano, T. Tomai, J. Tscheuschner, J. Tsubota, T. Uesaka, Z. Yang, and K. Yoneda
Subjects: In-beam γ-ray spectroscopy, Island of inversion, Shell evolution, Physics, QC1-999
Abstract: Detailed γ-ray spectroscopy of the exotic neon isotope 28Ne has been performed for the first time using the one-neutron removal reaction from 29Ne on a liquid hydrogen target at 240 MeV/nucleon. Based on an analysis of parallel momentum distributions, a level scheme with spin-parity assignments has been constructed for 28Ne and the negative-parity states are identified for the first time. The measured partial cross sections and momentum distributions reveal a significant intruder p-wave strength providing evidence of the breakdown of the N=20 and N=28 shell gaps. Only a weak, possible f-wave strength was observed to bound final states. Large-scale shell-model calculations with different effective interactions do not reproduce the large p-wave and small f-wave strength observed experimentally, indicating an ongoing challenge for a complete theoretical description of the transition into the island of inversion along the Ne isotopic chain.
Published: 2023
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3. 4D-imaging of drip-line radioactivity by detecting proton emission from 54mNi pictured with ACTAR TPC

Author: J. Giovinazzo, T. Roger, B. Blank, D. Rudolph, B. A. Brown, H. Alvarez-Pol, A. Arokia Raj, P. Ascher, M. Caamaño-Fresco, L. Caceres, D. M. Cox, B. Fernández-Domínguez, J. Lois-Fuentes, M. Gerbaux, S. Grévy, G. F. Grinyer, O. Kamalou, B. Mauss, A. Mentana, J. Pancin, J. Pibernat, J. Piot, O. Sorlin, C. Stodel, J.-C. Thomas, and M. Versteegen
Subjects: Science
Abstract: Proton radioactivity is useful for studying nuclear structure. Here the authors report two proton emission branches from the 10+ state isomer of 54mNi by using a time projection chamber.
Published: 2021
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4. Mirror symmetry at mass A = 54: E4 effective charges near doubly magic 56Ni

Author: D. Rudolph, B. Blank, J. Giovinazzo, T. Roger, H. Alvarez-Pol, A. Arokia Raj, P. Ascher, M. Caamaño-Fresco, L. Caceres, D.M. Cox, B. Fernández-Domínguez, J. Lois-Fuentes, M. Gerbaux, S. Grévy, G.F. Grinyer, O. Kamalou, B. Mauss, A. Mentana, J. Pancin, J. Pibernat, J. Piot, O. Sorlin, C. Stodel, J.-C. Thomas, and M. Versteegen
Subjects: 54Ni, Nuclear shell model, Isospin symmetry, Electromagnetic decay, E4 transition, Effective charges, Physics, QC1-999
Abstract: Proton-emission branches of the 10+ isomer in the Tz=−1 nucleus 54Ni have been imaged with the active target and time projection chamber (ACTAR TPC) in an experiment conducted at the Grand Accélérateur National d'Ions Lourds (GANIL). The completed decay scheme allows derivation of the reduced transition strengths, B(E2;10+→8+) and B(E4;10+→6+), for the two competing γ-ray transitions. By means of a comparison with their well-known ‘mirror transitions’ in Tz=+1 54Fe, and aided by a variety of shell-model calculations in the fp model space, effective charges for E4 transitions near N=Z 56Ni can be deduced: επ≈1.40 and εν≈0.30. Mirror-energy differences are explored with various shell-model interactions and isospin-symmetry breaking terms.
Published: 2022
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5. Neutron-proton pairing in the N=Z radioactive fp-shell nuclei 56Ni and 52Fe probed by pair transfer

Author: B. Le Crom, M. Assié, Y. Blumenfeld, J. Guillot, H. Sagawa, T. Suzuki, M. Honma, N.L. Achouri, B. Bastin, R. Borcea, W.N. Catford, E. Clément, L. Cáceres, M. Caamaño, A. Corsi, G. De France, F. Delaunay, N. De Séréville, B. Fernandez-Dominguez, M. Fisichella, S. Franchoo, A. Georgiadou, J. Gibelin, A. Gillibert, F. Hammache, O. Kamalou, A. Knapton, V. Lapoux, S. Leblond, A.O. Macchiavelli, F.M. Marqués, A. Matta, L. Ménager, P. Morfouace, N.A. Orr, J. Pancin, X. Pereira-Lopez, L. Perrot, J. Piot, E. Pollacco, D. Ramos, T. Roger, F. Rotaru, A.M. Sánchez-Benítez, M. Sénoville, O. Sorlin, M. Stanoiu, I. Stefan, C. Stodel, D. Suzuki, J.-C. Thomas, and M. Vandebrouck
Subjects: Radioactive beam, Direct reactions, Neutron-proton pairing, Cooper pairs, Physics, QC1-999
Abstract: The isovector and isoscalar components of neutron-proton pairing are investigated in the N=Z unstable nuclei of the fp-shell through the two-nucleon transfer reaction (p,3He) in inverse kinematics. The combination of particle and gamma-ray detection with radioactive beams of 56Ni and 52Fe, produced by fragmentation at the GANIL/LISE facility, made it possible to carry out this study for the first time in a closed and an open-shell nucleus in the fp-shell. The transfer cross-sections for ground-state to ground-state (J=0+, T=1) and to the first (J=1+, T=0) state were extracted for both cases together with the transfer cross-section ratios σ(0+,T=1)/σ(1+,T=0). They are compared with second-order distorted-wave born approximation (DWBA) calculations. The enhancement of the ground-state to ground-state pair transfer cross-section close to mid-shell, in 52Fe, points towards a superfluid phase in the isovector channel. For the “deuteron-like” transfer, very low cross-sections to the first (J=1+, T=0) state were observed both for 56Ni(p,3He) and 52Fe(p,3He) and are related to a strong hindrance of this channel due to spin-orbit effect. No evidence for an isoscalar deuteron-like condensate is observed.
Published: 2022
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6. Author Correction: 4D-imaging of drip-line radioactivity by detecting proton emission from 54mNi pictured with ACTAR TPC

Author: J. Giovinazzo, T. Roger, B. Blank, D. Rudolph, B. A. Brown, H. Alvarez-Pol, A. Arokia Raj, P. Ascher, M. Caamaño-Fresco, L. Caceres, D. M. Cox, B. Fernández-Domínguez, J. Lois-Fuentes, M. Gerbaux, S. Grévy, G. F. Grinyer, O. Kamalou, B. Mauss, A. Mentana, J. Pancin, J. Pibernat, J. Piot, O. Sorlin, C. Stodel, J.-C. Thomas, and M. Versteegen
Subjects: Science
Published: 2022
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7. Quasi-free neutron and proton knockout reactions from light nuclei in a wide neutron-to-proton asymmetry range

Author: M. Holl, V. Panin, H. Alvarez-Pol, L. Atar, T. Aumann, S. Beceiro-Novo, J. Benlliure, C.A. Bertulani, J.M. Boillos, K. Boretzky, M. Caamaño, C. Caesar, E. Casarejos, W. Catford, J. Cederkall, L. Chulkov, D. Cortina-Gil, E. Cravo, I. Dillmann, P. Díaz Fernández, Z. Elekes, J. Enders, L.M. Fraile, D. Galaviz Redondo, R. Gernhäuser, P. Golubev, T. Heftrich, M. Heil, M. Heine, A. Heinz, A. Henriques, H.T. Johansson, B. Jonson, N. Kalantar-Nayestanaki, R. Kanungo, A. Kelic-Heil, T. Kröll, N. Kurz, C. Langer, T. Le Bleis, S. Lindberg, J. Machado, E. Nacher, M.A. Najafi, T. Nilsson, C. Nociforo, S. Paschalis, M. Petri, R. Reifarth, G. Ribeiro, C. Rigollet, D.M. Rossi, D. Savran, H. Scheit, H. Simon, O. Sorlin, I. Syndikus, O. Tengblad, Y. Togano, M. Vandebrouck, P. Velho, F. Wamers, H. Weick, C. Wheldon, G.L. Wilson, J.S. Winfield, P. Woods, M. Zhukov, and K. Zuber
Subjects: Physics, QC1-999
Abstract: The quasi-free scattering reactions 11C(p,2p) and 10,11,12C(p,pn) have been studied in inverse kinematics at beam energies of 300–400 MeV/u at the R3B-LAND setup. The outgoing proton-proton and proton-neutron pairs were detected in coincidence with the reaction fragments in kinematically complete measurements. The efficiency to detect these pairs has been obtained from GEANT4 simulations which were tested using the 12C(p,2p) and 12C(p,pn) reactions. Experimental cross sections and momentum distributions have been obtained and compared to DWIA calculations based on eikonal theory. The new results reported here are combined with previously published cross sections for quasi-free scattering from oxygen and nitrogen isotopes and together they enable a systematic study of the reduction of single-particle strength compared to predictions of the shell model over a wide neutron-to-proton asymmetry range. The combined reduction factors show a weak or no dependence on isospin asymmetry, in contrast to the strong dependency reported in nucleon-removal reactions induced by nuclear targets at lower energies. However, the reduction factors for (p,2p) are found to be 'significantly smaller than for (p,pn) reactions for all investigated nuclei. Keywords: Quasi-free scattering, Inverse kinematics, Shell model, Spectroscopic factors
Published: 2019
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8. Low-lying single-particle structure of 17C and the N = 14 sub-shell closure

Author: X. Pereira-López, B. Fernández-Domínguez, F. Delaunay, N.L. Achouri, N.A. Orr, W.N. Catford, M. Assié, S. Bailey, B. Bastin, Y. Blumenfeld, R. Borcea, M. Caamaño, L. Caceres, E. Clément, A. Corsi, N. Curtis, Q. Deshayes, F. Farget, M. Fisichella, G. de France, S. Franchoo, M. Freer, J. Gibelin, A. Gillibert, G.F. Grinyer, F. Hammache, O. Kamalou, A. Knapton, T. Kokalova, V. Lapoux, J.A. Lay, B. Le Crom, S. Leblond, J. Lois-Fuentes, F.M. Marqués, A. Matta, P. Morfouace, A.M. Moro, T. Otsuka, J. Pancin, L. Perrot, J. Piot, E. Pollacco, D. Ramos, C. Rodríguez-Tajes, T. Roger, F. Rotaru, M. Sénoville, N. de Séréville, R. Smith, O. Sorlin, M. Stanoiu, I. Stefan, C. Stodel, D. Suzuki, T. Suzuki, J.C. Thomas, N. Timofeyuk, M. Vandebrouck, J. Walshe, and C. Wheldon
Subjects: Physics, QC1-999
Abstract: The first investigation of the single-particle structure of the bound states of 17C, via the d(16C,p) transfer reaction, has been undertaken. The measured angular distributions confirm the spin-parity assignments of 1/2+ and 5/2+ for the excited states located at 217 and 335 keV, respectively. The spectroscopic factors deduced for these states exhibit a marked single-particle character, in agreement with shell model and particle-core model calculations, and combined with their near degeneracy in energy provide clear evidence for the absence of the N=14 sub-shell closure. The very small spectroscopic factor found for the 3/2+ ground state is consistent with theoretical predictions and indicates that the ν1d3/2 strength is carried by unbound states. With a dominant ℓ=0 valence neutron configuration and a very low separation energy, the 1/2+ excited state is a one-neutron halo candidate.
Published: 2020
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9. Probing the Z = 6 spin-orbit shell gap with (p,2p) quasi-free scattering reactions

Author: I. Syndikus, M. Petri, A.O. Macchiavelli, S. Paschalis, C.A. Bertulani, T. Aumann, H. Alvarez-Pol, L. Atar, S. Beceiro-Novo, J. Benlliure, J.M. Boillos, K. Boretzky, M.J.G. Borge, B.A. Brown, M. Caamaño, C. Caesar, E. Casarejos, W. Catford, J. Cederkall, S. Chakraborty, L.V. Chulkov, D. Cortina-Gil, E. Cravo, R. Crespo, U. Datta Pramanik, I. Dillmann, P. Díaz Fernández, Z. Elekes, J. Enders, F. Farinon, L.M. Fraile, D. Galaviz, H. Geissel, R. Gernhäuser, P. Golubev, K. Göbel, M. Heil, M. Heine, A. Heinz, A. Henriques, M. Holl, H.T. Johansson, B. Jonson, N. Kalantar-Nayestanaki, R. Kanungo, A. Kelic-Heil, T. Kröll, N. Kurz, C. Langer, T. Le Bleis, J. Machado, J. Marganiec-Gałązka, E. Nacher, T. Nilsson, C. Nociforo, V. Panin, A. Perea, S.B. Pietri, R. Plag, A. Rahaman, R. Reifarth, A. Revel, G. Ribeiro, C. Rigollet, D.M. Rossi, D. Savran, H. Scheit, H. Simon, O. Sorlin, O. Tengblad, Y. Togano, M. Vandebrouck, V. Volkov, F. Wamers, C. Wheldon, G.L. Wilson, J.S. Winfield, H. Weick, P. Woods, D. Yakorev, M. Zhukov, A. Zilges, and K. Zuber
Subjects: Quasi-free scattering reactions, Magic numbers, Spin-orbit splitting, Tensor force, Shell evolution, Exotic nuclei, Physics, QC1-999
Abstract: The evolution of the traditional nuclear magic numbers away from the valley of stability is an active field of research. Experimental efforts focus on providing key spectroscopic information that will shed light into the structure of exotic nuclei and understanding the driving mechanism behind the shell evolution. In this work, we investigate the Z=6 spin-orbit shell gap towards the neutron dripline. To do so, we employed NA(p,2p)CA−1 quasi-free scattering reactions to measure the proton component of the 21+ state of 16,18,20C. The experimental findings support the notion of a moderate reduction of the proton 1p1/2−1p3/2 spin-orbit splitting, at variance to recent claims for a prevalent Z=6 magic number towards the neutron dripline.
Published: 2020
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10. Reduced spin-orbit splitting in 35Si: Weak binding or density-depletion effect?

Author: O. Sorlin, F. de Oliveira Santos, and J.P. Ebran
Subjects: Physics, QC1-999
Abstract: The reduction of the neutron spin-orbit (SO) splitting 2p3/2−2p1/2 between the 41Ca and 35Si isotones is a unique feature throughout the chart of nuclides, as the SO splitting usually increases with decreasing A. The way it is reduced, either gradually between 41Ca and 35Si or abruptly between 37S and 35Si, as well as the origin of its reduction, whether from the weak binding energy of the p states or from the sudden depletion in the central proton density moving to 35Si, are subject of debate. The results reported here using the self-consistent Covariant Energy Density Functional calculations with the DD-ME2 parametrization rather point to an abrupt, local decrease in 35Si, and to the large dominance of the central density depletion effect. It is concluded that weak binding, central density depletion as well as correlations must be taken into account to fully evaluate the amplitude and causes of this SO splitting reduction. To broaden the scope of the present work, discussions also include the recent experimental results of proton and neutron SO splittings around 132Sn and 56Ni.
Published: 2020
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11. Neutron-rich nuclei produced at zero degrees in damped collisions induced by a beam of 18O on a 238U target

Author: I. Stefan, B. Fornal, S. Leoni, F. Azaiez, C. Portail, J.C. Thomas, A.V. Karpov, D. Ackermann, P. Bednarczyk, Y. Blumenfeld, S. Calinescu, A. Chbihi, M. Ciemala, N. Cieplicka-Oryńczak, F.C.L. Crespi, S. Franchoo, F. Hammache, Ł.W. Iskra, B. Jacquot, R.V.F. Janssens, O. Kamalou, T. Lauritsen, M. Lewitowicz, L. Olivier, S.M. Lukyanov, M. Maccormick, A. Maj, P. Marini, I. Matea, M.A. Naumenko, F. de Oliveira Santos, C. Petrone, Yu.E. Penionzhkevich, F. Rotaru, H. Savajols, O. Sorlin, M. Stanoiu, B. Szpak, O.B. Tarasov, and D. Verney
Subjects: Physics, QC1-999
Abstract: Cross sections and corresponding momentum distributions have been measured for the first time at zero degrees for the exotic nuclei obtained from a beam of 18O at 8.5 MeV/A impinging on a 1 mg/cm2 238U target. Sizable cross sections were found for the production of exotic species arising from the neutron transfer and proton removal from the projectile. Comparisons of experimental results with calculations based on deep-inelastic reaction models, taking into account the particle evaporation process, indicate that zero degree is a scattering angle at which the differential reaction cross section for production of exotic nuclei is at its maximum. This result is important in view of the new generation of zero degrees spectrometers under construction, such as the S3 separator at GANIL, for example. Keywords: Nuclear reactions, Deep-inelastic collisions, Exotic nuclei
Published: 2018
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12. An above-barrier narrow resonance in 15F

Author: F. de Grancey, A. Mercenne, F. de Oliveira Santos, T. Davinson, O. Sorlin, J.C. Angélique, M. Assié, E. Berthoumieux, R. Borcea, A. Buta, I. Celikovic, V. Chudoba, J.M. Daugas, G. Dumitru, M. Fadil, S. Grévy, J. Kiener, A. Lefebvre-Schuhl, N. Michel, J. Mrazek, F. Negoita, J. Okołowicz, D. Pantelica, M.G. Pellegriti, L. Perrot, M. Płoszajczak, G. Randisi, I. Ray, O. Roig, F. Rotaru, M.G. Saint Laurent, N. Smirnova, M. Stanoiu, I. Stefan, C. Stodel, K. Subotic, V. Tatischeff, J.C. Thomas, P. Ujić, and R. Wolski
Subjects: Resonances, Elastic proton scattering, lifetimes, width, 15F, Unbound states, Overbarrier resonance, Physics, QC1-999
Abstract: Intense and purified radioactive beam of post-accelerated 14O was used to study the low-lying states in the unbound 15F nucleus. Exploiting resonant elastic scattering in inverse kinematics with a thick target, the second excited state, a resonance at ER=4.757(6)(10) MeV with a width of Γ=36(5)(14) keV was measured for the first time with high precision. The structure of this narrow above-barrier state in a nucleus located two neutrons beyond the proton drip line was investigated using the Gamow Shell Model in the coupled channel representation with a 12C core and three valence protons. It is found that it is an almost pure wave function of two quasi-bound protons in the 2s1/2 shell.
Published: 2016
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13. Evolution of single-particle strength in neutron-rich 71Cu

Author: P. Morfouace, S. Franchoo, K. Sieja, I. Matea, L. Nalpas, M. Niikura, A.M. Sánchez-Benítez, I. Stefan, M. Assié, F. Azaiez, D. Beaumel, S. Boissinot, C. Borcea, R. Borcea, G. Burgunder, L. Cáceres, N. De Séréville, Zs. Dombrádi, J. Elseviers, B. Fernández-Domínguez, A. Gillibert, S. Giron, S. Grévy, F. Hammache, O. Kamalou, V. Lapoux, L. Lefebvre, A. Lepailleur, C. Louchart, G. Marquinez-Duran, I. Martel, A. Matta, D. Mengoni, D.R. Napoli, F. Recchia, J.-A. Scarpaci, D. Sohler, O. Sorlin, M. Stanoiu, C. Stodel, J.-C. Thomas, and Zs. Vajta
Subjects: Physics, QC1-999
Abstract: The strength functions of the πf5/2, πp3/2 and πf7/2 orbitals in neutron-rich 71Cu were obtained in a 72Zn(d,3He)71Cu proton pick-up reaction in inverse kinematics using a radioactive beam of 72Zn at 38 MeV/u. A dedicated set-up was developed to overcome the experimental challenges posed by the low cross section of the reaction and the low energy of the outgoing 3He particles. The excitation-energy spectrum was reconstructed and spectroscopic factors were obtained after analysis of the angular distributions with the finite-range Distorted-Wave Born Approximation (DWBA). The results show that unlike for the πf5/2 orbital and contrary to earlier interpretation, the πf7/2 single-particle strength distribution is not appreciably affected by the addition of neutrons beyond N=40.
Published: 2015
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14. Structure of Ca36 under the Coulomb Magnifying Glass

Author: L. Lalanne, O. Sorlin, A. Poves, M. Assié, F. Hammache, S. Koyama, D. Suzuki, F. Flavigny, V. Girard-Alcindor, A. Lemasson, A. Matta, T. Roger, D. Beaumel, Y. Blumenfeld, B. A. Brown, F. De Oliveira Santos, F. Delaunay, N. de Séréville, S. Franchoo, J. Gibelin, J. Guillot, O. Kamalou, N. Kitamura, V. Lapoux, B. Mauss, P. Morfouace, M. Niikura, J. Pancin, T. Y. Saito, C. Stodel, and J-C. Thomas
Subjects: General Physics and Astronomy
Published: 2022

15. New narrow resonances observed in the unbound nucleus F15

Author: V. Girard-Alcindor, A. Mercenne, I. Stefan, F. de Oliveira Santos, N. Michel, M. Płoszajczak, M. Assié, A. Lemasson, E. Clément, F. Flavigny, A. Matta, D. Ramos, M. Rejmund, J. Dudouet, D. Ackermann, P. Adsley, M. Assunção, B. Bastin, D. Beaumel, G. Benzoni, R. Borcea, A. J. Boston, D. Brugnara, L. Cáceres, B. Cederwall, I. Celikovic, V. Chudoba, M. Ciemala, J. Collado, F. C. L. Crespi, G. D'Agata, G. De France, F. Delaunay, C. Diget, C. Domingo-Pardo, J. Eberth, C. Fougères, S. Franchoo, F. Galtarossa, A. Georgiadou, J. Gibelin, S. Giraud, V. González, N. Goyal, A. Gottardo, J. Goupil, S. Grévy, V. Guimaraes, F. Hammache, L. J. Harkness-Brennan, H. Hess, N. Jovančević, D. S. Judson Oliver, O. Kamalou, A. Kamenyero, J. Kiener, W. Korten, S. Koyama, M. Labiche, L. Lalanne, V. Lapoux, S. Leblond, A. Lefevre, C. Lenain, S. Leoni, H. Li, A. Lopez-Martens, A. Maj, I. Matea, R. Menegazzo, D. Mengoni, A. Meyer, B. Million, B. Monteagudo, P. Morfouace, J. Mrazek, M. Niikura, J. Piot, Zs. Podolyak, C. Portail, A. Pullia, B. Quintana, F. Recchia, P. Reiter, K. Rezynkina, T. Roger, J. S. Rojo, F. Rotaru, M. D. Salsac, A. M. Sánchez Benítez, E. Sanchis, M. Şenyigit, N. de Séréville, M. Siciliano, J. Simpson, D. Sohler, O. Sorlin, M. Stanoiu, C. Stodel, D. Suzuki, C. Theisen, D. Thisse, J. C.Thomas, P. Ujic, J. J. Valiente-Dobón, and M. Zielińska
Published: 2022

16. Neutron-proton pairing in the N=Z radioactive fp-shell nuclei $^{56}$Ni and $^{52}$Fe probed by pair transfer

Author: B. Le Crom, M. Assié, Y. Blumenfeld, J. Guillot, H. Sagawa, T. Suzuki, M. Honma, N.L. Achouri, B. Bastin, R. Borcea, W.N. Catford, E. Clément, L. Cáceres, M. Caamaño, A. Corsi, G. De France, F. Delaunay, N. De Séréville, B. Fernandez-Dominguez, M. Fisichella, S. Franchoo, A. Georgiadou, J. Gibelin, A. Gillibert, F. Hammache, O. Kamalou, A. Knapton, V. Lapoux, S. Leblond, A.O. Macchiavelli, F.M. Marqués, A. Matta, L. Ménager, P. Morfouace, N.A. Orr, J. Pancin, X. Pereira-Lopez, L. Perrot, J. Piot, E. Pollacco, D. Ramos, T. Roger, F. Rotaru, A.M. Sánchez-Benítez, M. Sénoville, O. Sorlin, M. Stanoiu, I. Stefan, C. Stodel, D. Suzuki, J.-C. Thomas, M. Vandebrouck, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), 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)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)
Subjects: Nuclear and High Energy Physics, Nuclear Theory, Direct reactions, FOS: Physical sciences, Radioactive beam, Neutron-proton pairing, 22 Física, Nuclear Experiment (nucl-ex), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Cooper pairs
Abstract: The isovector and isoscalar components of neutron-proton pairing are investigated in the N=Z unstable nuclei of the \textit{fp}-shell through the two-nucleon transfer reaction (p,$^3$He) in inverse kinematics. The combination of particle and gamma-ray detection with radioactive beams of $^{56}$Ni and $^{52}$Fe, produced by fragmentation at the GANIL/LISE facility, made it possible to carry out this study for the first time in a closed and an open-shell nucleus in the \textit{fp}-shell. The transfer cross-sections for ground-state to ground-state (J=0$^+$,T=1) and to the first (J=1$^+$,T=0) state were extracted for both cases together with the transfer cross-section ratios $\sigma$(0$^+$,T=1) /$\sigma$(1$^+$,T=0). They are compared with second-order distorted-wave born approximation (DWBA) calculations. The enhancement of the ground-state to ground-state pair transfer cross-section close to mid-shell, in $^{52}$Fe, points towards a superfluid phase in the isovector channel. For the "deuteron-like" transfer, very low cross-sections to the first (J=1$^+$,T=0) state were observed both for \Ni\phe\, and \Fe\phe\, and are related to a strong hindrance of this channel due to spin-orbit effect. No evidence for an isoscalar deuteron-like condensate is observed., Comment: 7 pages, 4 figures
Published: 2022

17. Structure of ^{36}Ca under the Coulomb Magnifying Glass

Author: L, Lalanne, O, Sorlin, A, Poves, M, Assié, F, Hammache, S, Koyama, D, Suzuki, F, Flavigny, V, Girard-Alcindor, A, Lemasson, A, Matta, T, Roger, D, Beaumel, Y, Blumenfeld, B A, Brown, F De Oliveira, Santos, F, Delaunay, N, de Séréville, S, Franchoo, J, Gibelin, J, Guillot, O, Kamalou, N, Kitamura, V, Lapoux, B, Mauss, P, Morfouace, M, Niikura, J, Pancin, T Y, Saito, C, Stodel, and J-C, Thomas
Abstract: Detailed spectroscopy of the neutron-deficient nucleus ^{36}Ca was obtained up to 9 MeV using the ^{37}Ca(p,d)^{36}Ca and the ^{38}Ca(p,t)^{36}Ca transfer reactions. The radioactive nuclei, produced by the LISE spectrometer at GANIL, interacted with the protons of the liquid hydrogen target CRYPTA, to produce light ejectiles (the deuteron d or triton t) that were detected in the MUST2 detector array, in coincidence with the heavy residues identified by a zero-degree detection system. Our main findings are (i) a similar shift in energy for the 1_{1}^{+} and 2_{1}^{+} states by about -250 keV, as compared with the mirror nucleus ^{36}S; (ii) the discovery of an intruder 0_{2}^{+} state at 2.83(13) MeV, which appears below the first 2^{+} state, in contradiction with the situation in ^{36}S; and (iii) a tentative 0_{3}^{+} state at 4.83(17) MeV, proposed to exhibit a bubble structure with two neutron vacancies in the 2s_{1/2} orbit. The inversion between the 0_{2}^{+} and 2_{1}^{+} states is due to the large mirror energy difference (MED) of -516(130) keV for the former. This feature is reproduced by shell model calculations, using the sd-pf valence space, predicting an almost pure intruder nature for the 0_{2}^{+} state, with two protons (neutrons) being excited across the Z=20 magic closure in ^{36}Ca (^{36}S). This mirror system has the largest MEDs ever observed, if one excludes the few cases induced by the effect of the continuum.
Published: 2021

18. Coulomb and nuclear excitations of Zn70 and Ni68 at intermediate energy

Author: G. de Angelis, J. Mrazek, L. Perrot, R. Borcea, R. Astabatyan, F. Carstoiu, H. Guerin, M. Stanoiu, T. Roger, S. Grévy, L. Stuhl, C. Petrone, Zs. Podolyák, M. N. Harakeh, A. Lepailleur, J. C. Thomas, L. Cáceres, D. D. Dao, I. Stefan, F. Negoita, M. Krzysiek, A. Gottardo, V. Maslov, S. Bagchi, C. Borcea, Dóra Sohler, I. Matea, O. Wieland, Z. Vajta, F. Nowacki, M. Vandebrouck, P. Morfouace, F. Rotaru, S. Lukyanov, I. Kuti, O. Sorlin, Megumi Niikura, S. Franchoo, A. Krasznahorkay, K. Mazurek, Y. Penionzhkevich, M. Ciemála, A. Maj, Zsolt Dombrádi, C. Rigollet, M. Kmiecik, I. M. Harca, Eric Clément, O. Kamalou, S. Calinescu, and L. Olivier
Subjects: Physics, Proton, 010308 nuclear & particles physics, Prolate spheroid, 01 natural sciences, Spectral line, Intermediate energy, 0103 physical sciences, Oblate spheroid, Coulomb, Atomic physics, 010306 general physics, Beam energy, Excitation
Abstract: The reduced transition probabilities B ( E 2 ; 0 g.s. + → 2 1 + , 2 2 + ) in Zn 70 and the full B ( E 2 ; 0 g.s. + → 2 + ) strength up to S n = 7.79 MeV in Ni 68 have been determined at the LISE/GANIL facility using the Coulomb-excitation technique at intermediate beam energy on a Pb 208 target. The γ rays emitted in-flight were detected with an array of 46 BaF 2 crystals. The angles of the deflected nuclei were determined in order to disentangle and extract the Coulomb and nuclear contributions to the excitation of the 2 + states. The measured B ( E 2 ; 0 g.s. + → 2 1 + ) of 1432(124) e 2 fm 4 for Zn 70 falls in the lower part of the published values which clustered either around 1600 or above 2000 e 2 fm 4 , while the B ( E 2 ; 0 g.s. + → 2 2 + ) of 53(7) e 2 fm 4 agrees very well with the two published values. The relatively low B ( E 2 ; 0 g.s. + → 2 1 + ) of 301(38) e 2 fm 4 for Ni 68 agrees with previous studies and confirms a local magicity at Z = 28 , N = 40 . Combining the results of the low-energy spectra of Ni 68 and Zn 70 and their shell-model interpretations, it is interesting to notice that four different shapes (spherical, oblate, prolate, and triaxial) are present. Finally, a summed E 2 strength of only about 150 e 2 fm 4 has been found experimentally at high excitation energy, likely due to proton excitations across the Z = 28 gap. The experimental distribution of this high-energy E 2 excitation agrees with shell-model calculations, but its strength is about two times weaker.
Published: 2021

19. Proton 3D tracking and emission time from a short-lived isomer with ACTAR TPC

Author: J. Giovinazzo, T. Roger, B. Blank, D. Rudolph, H. Alvarez-Pol, A. Arokiaraj, P. Ascher, M. Camaaño-Fresco, L. Caceres, D.M. Cox, B. Fernández-Domínguez, J. Lois-Fuentes, M. Gerbaux, S. Grévy, G.F. Grinyer, O. Kamalou, B. Mauss, A. Mentana, A. Ortega Moral, J. Pancin, J. Pibernat, J. Piot, O. Sorlin, C. Stodel, J.-C. Thomas, M. Versteegen, Laboratoire de Physique des Deux Infinis Bordeaux (LP2I - Bordeaux), Université de Bordeaux (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Subjects: p: tracks, data analysis method, Nuclear and High Energy Physics, track data analysis, Short-lived decays, ACTAR TPC, Proton radioactivity, tracks: length, Track reconstruction, time projection chamber, nickel: nuclide, efficiency, radioactivity, decay: time, branching ratio, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Instrumentation
Abstract: International audience; An experiment was conducted at the GANIL/LISE3 facility to produce the 10+ isomer of 54Ni and measure its proton radioactivity decay branches. The proton detection was achieved with the ACTAR TPC device that enabled the separation of the small signal of the emitted proton from the large signal of the implanted ion, while the decay half-life is of the order of 150 ns. From the measured data, the emitted proton track length and the decay time of the ion can be extracted simultaneously. The full proton radioactivity pattern could be established, with two emission branches and their relative branching ratio. Data processing and analysis that allowed to identify and separate the ion and the proton signals in order to reconstruct the particles trajectories and decay time are detailed. The evaluation of the detection efficiency for the proton radioactivity branches based on a full simulation is described.
Published: 2022

20. 4D-imaging of drip-line radioactivity by detecting proton emission from Ni-54m pictured with ACTAR TPC

Author: M. Versteegen, J. Giovinazzo, Dirk Rudolph, O. Sorlin, P. Ascher, T. Roger, A. Arokia Raj, B. Fernández-Domínguez, J. Piot, Daniel Cox, M. Caamaño-Fresco, H. Alvarez-Pol, O. Kamalou, J. C. Thomas, B. Mauss, J. Pancin, M. Gerbaux, L. Cáceres, C. Stodel, J. Lois-Fuentes, J. Pibernat, B. Blank, S. Grévy, A. Mentana, B. A. Brown, G. F. Grinyer, 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), Grand Accélérateur National d'Ions Lourds (GANIL), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)
Subjects: Proton, Physics::Instrumentation and Detectors, Science, Nuclear Theory, ACTIVE TARGET, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Article, General Biochemistry, Genetics and Molecular Biology, Techniques and instrumentation, Nuclear physics, Quantum state, 0103 physical sciences, Quantum system, Experimental nuclear physics, Proton emission, 010306 general physics, Wave function, Nuclear Experiment, Quantum tunnelling, Physics, Multidisciplinary, Science & Technology, 010308 nuclear & particles physics, Nuclear shell model, General Chemistry, NUCLEAR-PHYSICS, Multidisciplinary Sciences, Theoretical nuclear physics, Atomic nucleus, SHELL-MODEL, Physics::Accelerator Physics, Science & Technology - Other Topics, SYSTEM
Abstract: Proton radioactivity was discovered exactly 50 years ago. First, this nuclear decay mode sets the limit of existence on the nuclear landscape on the neutron-deficient side. Second, it comprises fundamental aspects of both quantum tunnelling as well as the coupling of (quasi)bound quantum states with the continuum in mesoscopic systems such as the atomic nucleus. Theoretical approaches can start either from bound-state nuclear shell-model theory or from resonance scattering. Thus, proton-radioactivity guides merging these types of theoretical approaches, which is of broader relevance for any few-body quantum system. Here, we report experimental measurements of proton-emission branches from an isomeric state in 54mNi, which were visualized in four dimensions in a newly developed detector. We show that these decays, which carry an unusually high angular momentum, ℓ = 5 and ℓ = 7, respectively, can be approximated theoretically with a potential model for the proton barrier penetration and a shell-model calculation for the overlap of the initial and final wave functions., Proton radioactivity is useful for studying nuclear structure. Here the authors report two proton emission branches from the 10+ state isomer of 54mNi by using a time projection chamber.
Published: 2021

21. Evaluation of the K35(p,γ)Ca36 reaction rate using the Ca37(p,d)Ca36 transfer reaction

Author: J. Pancin, L. Lalanne, Tomoki Saito, Franck Delaunay, Julien Gibelin, Megumi Niikura, B. Mauss, A. Lemasson, Daisuke Suzuki, N. Kitamura, O. Sorlin, Didier Beaumel, Jérôme Guillot, J. C. Thomas, André Palma da Cunha Matta, P. Morfouace, F. de Oliveira Santos, S. Franchoo, C. Stodel, A. Poves, N. de Sereville, M. Assié, F. Hammache, Y. Blumenfeld, F. Flavigny, V. Lapoux, O. Kamalou, V. Girard-Alcindor, B. A. Brown, Shoko Koyama, and T. Roger
Subjects: Physics, Range (particle radiation), Proton, 010308 nuclear & particles physics, Resonance, Light curve, 01 natural sciences, 7. Clean energy, Atomic mass, Charged particle, Reaction rate, Recoil, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract: Background: A recent sensitivity study has shown that the K35(p,γ)Ca36 reaction is one of the ten (p,γ) reaction rates that could significantly impact the shape of the calculated x-ray burst light curve. Its reaction rate used up to now in type I x-ray burst calculations was estimated using an old measurement for the mass of Ca36 and theoretical predictions for the partial decay widths of the first 2+ resonance with arbitrary uncertainties. Purpose: In this work, we propose to reinvestigate the K35(p,γ)Ca36 reaction rate, as well as related uncertainties, by determining the energies and decay branching ratios of Ca36 levels, within the Gamow window of x-ray bursts, in the 0.5 to 2 GK temperature range. Method: These properties were studied by means of the one-neutron pickup transfer reaction Ca37(p,d)Ca36 in inverse kinematics using a radioactive beam of Ca37 at 48 MeV nucleon−1. The experiment was performed at the GANIL facility using the liquid hydrogen target CRYPTA, the MUST2 charged particle detector array for the detection of the light charged particles, and a zero degree detection system for the outgoing heavy recoil nuclei. Results: The atomic mass of Ca36 is confirmed and new resonances have been proposed together with their proton decay branching ratios. This spectroscopic information, used in combination with very recent theoretical predictions for the γ-decay width, were used to calculate the K35(p,γ)Ca36 reaction rate. The recommended rate of the present work was obtained within a uncertainty factor of 2 at 1σ. This is consistent with the previous estimate in the x-ray burst temperature range. A large increase of the reaction rate was found at higher temperatures due to two newly discovered resonances. Conclusions: The K35(p,γ)Ca36 thermonuclear reaction rate is now well constrained by the present work in a broad range of temperatures covering those relevant to type I x-ray bursts. Our results show that the K35(p,γ)Ca36 reaction does not affect the shape of the x-ray burst light curve, and that it can be removed from the list of the few influential proton radiative captures reactions having a strong impact on the light curve.
Published: 2021

22. Coulomb and nuclear excitations of Zn 70 and Ni 68 at intermediate energy

Author: S. Calinescu, O. Sorlin, I. Matea, F. Carstoiu, D. D. Dao, F. Nowacki, G. de Angelis, R. Astabatyan, S. Bagchi, C. Borcea, R. Borcea, L. Cáceres, M. Ciemála, E. Clément, Z. Dombrádi, S. Franchoo, A. Gottardo, S. Grévy, H. Guerin, M. N. Harakeh, I. M. Harca, O. Kamalou, M. Kmiecik, A. Krasznahorkay, M. Krzysiek, I. Kuti, A. Lepailleur, S. Lukyanov, A. Maj, V. Maslov, K. Mazurek, P. Morfouace
Published: 2021
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23. A liquid hydrogen target for radioactive beam experiments using the missing mass method

Author: Hideaki Otsu, L. Lalanne, O. Sorlin, Megumi Niikura, Daisuke Suzuki, Takumi Saito, Shoko Koyama, M. Assié, N. Kitamura, 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 des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), 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, Radionuclide, Resolution (mass spectrometry), 010308 nuclear & particles physics, Aperture, Liquid hydrogen target, Mass spectrometry, 01 natural sciences, 7. Clean energy, Missing mass spectroscopy, 0103 physical sciences, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Atomic physics, Radioactive ion beam, Nuclear Experiment, 010306 general physics, Ground state, Instrumentation, Liquid hydrogen, Excitation, Beam (structure)
Abstract: International audience; We developed a liquid hydrogen target dedicated to missing mass spectroscopy using radioactive isotope beams. The target has a circular aperture of 20 mm and a maximum thickness of 1.5 mm at the center. A test experiment with a 12C beam at 54.4 MeV/u was performed at GANIL. The 12C(p,d)11C reaction was measured with the charged-particle telescopes MUST2. An excitation energy resolution of 500-keV r.m.s. was obtained for the observed ground state. The target thickness was confirmed from the comparison of the measured differential cross sections to previous measurements.
Published: 2021

24. Probing nuclear forces beyond the nuclear drip line: the cases of $^{16}$F and $^{15}$F: A Tribute to Mahir Hussein

Author: L. Caceres, A.M. Sánchez Benítez, Igor T. Čeliković, A. Matta, D. Verney, F. Rotaru, Valdir Guimaraes, P. Adsley, O. Sorlin, J. Guillot, T. Roger, C. Portail, V. Girard-Alcindor, I. Matea, A. Georgiadou, C. Petrone, D. Pantelica, R. Borcea, D. Suzuki, O. Kamalou, V. Lapoux, Megumi Niikura, I. Stefan, J. Piot, F. Flavigny, G. D’Agata, F. de Oliveira Santos, M. Ciemala, V. Tatischeff, V. Chudoba, L. Lalanne, C. Stodel, J. C. Thomas, N. Goyal, M. Stanoiu, C. Fougeres, S. Grévy, F. Negoita, N. de Séréville, L. Perrot, G. Dumitru, M. Assie, A. Meyer, J. C. Angelique, Marlete Assunção, Nicolas Michel, F. Hammache, D. Beaumel, S. Franchoo, Predrag Ujić, Dieter Ackermann, Shoko Koyama, F. de Grancey, J. Kiener, E. Berthoumieux, P. Morfouace, J. Mrazek, K. Subotic, 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 des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), 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 Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Elastic scattering, Physics, Nuclear and High Energy Physics, Proton, 010308 nuclear & particles physics, media_common.quotation_subject, Hadron, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Asymmetry, Excited state, 0103 physical sciences, Nuclear force, Mirror nuclei, Atomic physics, 010306 general physics, Wave function, Nuclear Experiment, media_common
Abstract: The unbound proton-rich nuclei $$^{16}$$ F and $$^{15}$$ F are investigated experimentally and theoretically. Several experiments using the resonant elastic scattering method were performed at GANIL with radioactive beams to determine the properties of the low lying states of these nuclei. Strong asymmetry between $$^{16}$$ F– $$^{16}$$ N and $$^{15}$$ F– $$^{15}$$ C mirror nuclei is observed. The strength of the $$nucleon-nucleon$$ effective interaction involving the loosely bound proton in the $$s_{1/2}$$ orbit is significantly modified with respect to their mirror nuclei $$^{16}$$ N and $$^{15}$$ C. The reduction of the effective interaction is estimated by calculating the interaction energies with a schematic zero-range force. It is found that, after correcting for the effects due to changes in the radial distribution of the single-particle wave functions, the mirror symmetry of the $$n-p$$ interaction is preserved between $$^{16}$$ F and $$^{16}$$ N, while a difference of 63% is measured between the $$p-p$$ versus $$n-n$$ interactions in the second excited state of $$^{15}$$ F and $$^{15}$$ C nuclei. Several explanations are proposed.
Published: 2021

25. 4D-imaging of drip-line radioactivity by detecting proton emission from

Author: J, Giovinazzo, T, Roger, B, Blank, D, Rudolph, B A, Brown, H, Alvarez-Pol, A, Arokia Raj, P, Ascher, M, Caamaño-Fresco, L, Caceres, D M, Cox, B, Fernández-Domínguez, J, Lois-Fuentes, M, Gerbaux, S, Grévy, G F, Grinyer, O, Kamalou, B, Mauss, A, Mentana, J, Pancin, J, Pibernat, J, Piot, O, Sorlin, C, Stodel, J-C, Thomas, and M, Versteegen
Abstract: Proton radioactivity was discovered exactly 50 years ago. First, this nuclear decay mode sets the limit of existence on the nuclear landscape on the neutron-deficient side. Second, it comprises fundamental aspects of both quantum tunnelling as well as the coupling of (quasi)bound quantum states with the continuum in mesoscopic systems such as the atomic nucleus. Theoretical approaches can start either from bound-state nuclear shell-model theory or from resonance scattering. Thus, proton-radioactivity guides merging these types of theoretical approaches, which is of broader relevance for any few-body quantum system. Here, we report experimental measurements of proton-emission branches from an isomeric state in
Published: 2020

26. Structure of Si33 and the magicity of the N=20 gap at Z=14

Author: F. Rotaru, Kathrin Wimmer, A. Mutschler, A. Lemasson, F. Nowacki, H. Iwasaki, T. Roger, Alexandra Gade, S. R. Stroberg, C. Borcea, M. Vanderbrouck, D. Weisshaar, M. Wiedeking, R. Borcea, O. Sorlin, P. Papka, E. Khan, M. Stanoiu, A. Lepailleur, F. Recchia, D. Bazin, J. A. Tostevin, and S. Jongile
Subjects: Physics, education.field_of_study, Spectrometer, 010308 nuclear & particles physics, SHELL model, Population, Shell (structure), 01 natural sciences, Superconducting cyclotron, Atomic orbital, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, education, Beam (structure)
Abstract: The structure of ³³Si was studied by a one-neutron knockout reaction from a ³⁴Si beam at 98.5 MeV/u incident on a 9 Be target. The prompt γ rays following the de-excitation of ³³Si were detected using the GRETINA γ -ray tracking array while the reaction residues were identified on an event-by-event basis in the focal plane of the S800 spectrometer at the National Superconducting Cyclotron Laboratory. The presently derived spectroscopic factor values, C 2 S , for the 3 / 2 + and 1 / 2 + states, corresponding to a neutron removal from the 0 d 3 / 2 and 1 s 1 / 2 orbitals, agree with shell model calculations and point to a strong N = 20 shell closure. Three states arising from the more bound 0 d 5 / 2 orbital are proposed, one of which is unbound by about 930 keV. The sensitivity of this experiment has also confirmed a weak population of 9 / 2 − and 11 / 2 − 1 , 2 final states, which originate from a higher-order process. This mechanism may also have populated, to some fraction, the 3 / 2 − and 7 / 2 − negative-parity states, which hinders a determination of the C 2 S values for knockout from the normally unoccupied 1 p 3 / 2 and 0 f 7 / 2 orbits.
Published: 2020

27. Extending the Southern Shore of the Island of Inversion to F28

Author: J. Mayer, Noritsugu Nakatsuka, Michael Thoennessen, A. Gillibert, Ákos Horváth, Q. Deshayes, Yosuke Kondo, J. Tscheuschner, Nasser Kalantar-Nayestanaki, J. M. Gheller, István Kuti, M. Shikata, Thomas Aumann, C. Caesar, J. Tsubota, A. Revel, N. L. Achouri, W. He, Z. Elekes, Calem Hoffman, Shoichiro Kawase, Heiko Scheit, J. Kahlbow, Masahiro Yasuda, H. Simon, H. Sato, K. Yoneda, A. Horvat, K. Nakano, Igor Gašparić, T. Ozaki, H. Chae, J. A. Tostevin, L. Stuhl, K. Miki, F. de Oliveira Santos, H. L. Crawford, D. Calvet, Stefanos Paschalis, S. Masuoka, T. Isobe, A. Obertelli, Tomoki Saito, Momoko Tanaka, N. A. Orr, Shoko Koyama, Nobuyuki Chiga, L. Atar, Y. Satou, P. Fallon, Atsumi Saito, Zsolt Dombrádi, H. Törnqvist, Jongwon Hwang, A. Corsi, Julien Gibelin, K. Boretzky, A. Delbart, D. M. Rossi, H. Baba, Masaki Sasano, D. Sohler, V. Lapoux, M. A. Najafi, S. K. Kim, A. Hirayama, H. Al Falou, K. Kisamori, T. Tomai, V. Panin, P. Schrock, Takashi Nakamura, Yasuhiro Togano, M.N. Harakeh, M. Holl, Zaihong Yang, F. Nowacki, T. Kobayashi, Cenxi Yuan, D. Körper, Tomohiro Uesaka, Thomas Nilsson, C. A. Douma, Simon Lindberg, Hideaki Otsu, O. Sorlin, T. Murakami, Yohei Shimizu, Fabia Schindler, Franck Delaunay, F. M. Marqués, and Satoshi Takeuchi
Subjects: Physics, Proton, Island of inversion, General Physics and Astronomy, 01 natural sciences, Spectral line, Momentum, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Nucleon, Spectroscopy, Ground state
Abstract: Detailed spectroscopy of the neutron-unbound nucleus 28 F has been performed for the first time following proton/neutron removal from 29 Ne / 29 F beams at energies around 230 MeV / nucleon . The invariant-mass spectra were reconstructed for both the 27 F ( * ) + n and 26 F ( * ) + 2 n coincidences and revealed a series of well-defined resonances. A near-threshold state was observed in both reactions and is identified as the 28 F ground state, with S n ( 28 F ) = − 199 ( 6 ) keV , while analysis of the 2 n decay channel allowed a considerably improved S n ( 27 F ) = 1620 ( 60 ) keV to be deduced. Comparison with shell-model predictions and eikonal-model reaction calculations have allowed spin-parity assignments to be proposed for some of the lower-lying levels of 28 F . Importantly, in the case of the ground state, the reconstructed 27 F + n momentum distribution following neutron removal from 29 F indicates that it arises mainly from the 1 p 3 / 2 neutron intruder configuration. This demonstrates that the island of inversion around N = 20 includes 28 F , and most probably 29 F , and suggests that 28 O is not doubly magic.
Published: 2020

28. Probing the Z = 6 spin-orbit shell gap with (p,2p) quasi-free scattering reactions

Author: A. Henriques, J. S. Winfield, Thomas Nilsson, Rene Reifarth, M. Heine, E. Cravo, L. M. Fraile, Håkan T Johansson, O. Sorlin, L. Chulkov, W. N. Catford, A. Revel, J. Marganiec-Gałązka, Pavel Golubev, H. Scheit, S. Beceiro-Novo, Joakim Cederkäll, R. Gernhäuser, Carlos A. Bertulani, Y. Togano, T. Le Bleis, D. Cortina-Gil, L. Atar, G. L. Wilson, S. Pietri, F. Farinon, Kai Zuber, N. Kurz, Andreas Zilges, V. Volkov, M. Heil, C. Langer, A. Kelic-Heil, R. Plag, Catherine Rigollet, J. Enders, Iris Dillmann, U. Datta Pramanik, Jorge Machado, H. Alvarez-Pol, I. Syndikus, A. O. Macchiavelli, Marina Petri, D. Yakorev, M. Holl, Enrique Casarejos, G. Ribeiro, Mikhail V. Zhukov, Stefanos Paschalis, María José García Borge, Marine Vandebrouck, Deniz Savran, V. Panin, Björn Jonson, Nasser Kalantar-Nayestanaki, Philip Woods, Ángel Perea, C. Wheldon, R. Crespo, Thomas Aumann, Hans Geissel, Z. Elekes, Andreas Martin Heinz, J. M. Boillos, B. A. Brown, D. Galaviz, T. Kröll, S. Chakraborty, K. Göbel, Enrique Nácher, H. Weick, Rituparna Kanungo, P. Díaz Fernández, K. Boretzky, M. Caamaño, Anisur Rahaman, C. Caesar, J. Benlliure, F. Wamers, D. Rossi, Haik Simon, Olof Tengblad, C. Nociforo, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), R$^3$B, Energy and Sustainability Research Institute Groni, Research unit Nuclear & Hadron Physics, Royal Society (UK), Department of Energy (US), Federal Ministry of Education and Research (Germany), State of Hesse, Technische Universität Darmstadt, Helmholtz Association, European Young Investigator Awards, Swedish Research Council, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Xunta de Galicia, German Research Foundation, National Science Foundation (US), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)
Subjects: Nuclear and High Energy Physics, Quasi-free scattering reactions, Field (physics), Proton, Nuclear Theory, Shell (structure), FOS: Physical sciences, Shell evolution, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Atomic, Nuclear physics, Magic number (programming), Particle and Plasma Physics, 0103 physical sciences, Neutron, Nuclear, ddc:530, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Mathematical Physics, Spin-½, Physics, 010308 nuclear & particles physics, Scattering, Molecular, Spin-orbit splitting, Nuclear & Particles Physics, lcsh:QC1-999, 3. Good health, Valley of stability, Tensor force, Magic numbers, Física nuclear, lcsh:Physics, Astronomical and Space Sciences, Exotic nuclei
Abstract: 9 pags., 5 figs., 2 tabs., The evolution of the traditional nuclear magic numbers away from the valley of stability is an active field of research. Experimental efforts focus on providing key spectroscopic information that will shed light into the structure of exotic nuclei and understanding the driving mechanism behind the shell evolution. In this work, we investigate the Z=6 spin-orbit shell gap towards the neutron dripline. To do so, we employed NA(p,2p)CA−1 quasi-free scattering reactions to measure the proton component of the 2 state of C. The experimental findings support the notion of a moderate reduction of the proton 1p−1p spin-orbit splitting, at variance to recent claims for a prevalent Z=6 magic number towards the neutron dripline., This work was supported by the Royal Society award UF150476, UK STFC awards ST/M006433/1 and ST/P003885/1, U.S. Department of Energy, Office of Nuclear Physics, contract No. DE-AC02- 05CH11231 (LBNL), the German Federal Ministry of Education and Research (BMBF projects 05P15RDFN1, 05P15WOFNA and 05P19RDFN1), the GSI-TU Darmstadt cooperation agreement, the State of Hesse through the LOEWE center HIC for FAIR, the Helmholtz-Gemeinschaft through the graduate school HGS-HIRe and Young Investigators Grants, and the Swedish Research Council under contract number 621-2011-5324. This work was also supported by the Spanish research grants (Ministerio Ciencia e Innovación), FPA2015-64969-P, FPA2015-69640-C2-1-P, FPA2017- 87568-P, PGC2018-099746-B-C21, RTI2018-098868-B-I00, Undidad de Excelencia María de Maeztu under project MDM-2016.0692, and the Xunta de Galicia research grant GRC ED431C 2017/54. This work was partly supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Project-ID 279384907 - SFB 1245. C.A.B. acknowledges support from the U.S. NSF Grant No. 1415656, and U.S. DOE Grant No. DE-FG02-08ER41533.
Published: 2020

29. Low-lying single-particle structure of 17C and the N = 14 sub-shell closure

Author: Q. Deshayes, N. Curtis, F. Rotaru, Maria Fisichella, Franck Delaunay, S. Bailey, X. Pereira-López, Takaharu Otsuka, M. Assié, L. Caceres, F. M. Marqués, S. Franchoo, B. Le Crom, Julien Gibelin, Eric Clément, L. Perrot, A. Gillibert, A. Corsi, P. Morfouace, J. Walshe, S. Leblond, I. Stefan, G. F. Grinyer, J. C. Thomas, N. de Séréville, Daisuke Suzuki, Y. Blumenfeld, J. Piot, A. M. Moro, A. Matta, F. Farget, D. Ramos, R. Borcea, J. Lois-Fuentes, C. Wheldon, M. Stanoiu, N. L. Achouri, B. Bastin, C. Stodel, E. C. Pollacco, W. N. Catford, N. A. Orr, O. Sorlin, V. Lapoux, T. Kokalova, Robin Smith, Toshio Suzuki, T. Roger, Marine Vandebrouck, B. Fernández-Domínguez, Natalia Timofeyuk, A. Knapton, M. Sénoville, J. Pancin, M. Caamaño, Martin Freer, J. A. Lay, F. Hammache, C. Rodriguez-Tajes, O. Kamalou, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Consejo de Instalaciones Científicas y Tecnológicas de UKRI. Reino Unido, Agencia Estatal de Investigación. España, Ministerio de Economia, Industria y Competitividad (MINECO). España, Ministerio de Ciencia, Innovación y Universidades (MICINN). España, European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER), European Union (UE). H2020, Universidade de Santiago de Compostela [Spain] (USC ), 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), 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 des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Normandie Université (NU)-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, Valence (chemistry), 010308 nuclear & particles physics, SHELL model, Nuclear Theory, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Molecular physics, lcsh:QC1-999, Excited state, 0103 physical sciences, Bound state, Neutron, Halo, Nuclear Experiment (nucl-ex), 010306 general physics, Ground state, Nuclear Experiment, ComputingMilieux_MISCELLANEOUS, lcsh:Physics
Abstract: The first investigation of the single-particle structure of the bound states of 17C, via the d(16C, p) transfer reaction, has been undertaken. The measured angular distributions confirm the spin-parity assignments of 1/2+ and 5/2+ for the excited states located at 217 and 335 keV, respectively. The spectroscopic factors deduced for these states exhibit a marked single-particle character, in agreement with shell model and particle-core model calculations, and combined with their near degeneracy in energy provide clear evidence for the absence of the N = 14 sub-shell closure. The very small spectroscopic factor found for the 3/2+ ground state is consistent with theoretical predictions and indicates that the {\nu}1d3/2 strength is carried by unbound states. With a dominant l = 0 valence neutron configuration and a very low separation energy, the 1/2+ excited state is a one-neutron halo candidate., Comment: 7 pages, 5 figures, Accepted for publication in Physics Letters B
Published: 2020
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30. COMPASS—A COMPAct decay spectroscopy set-up

Author: O. Kaleja, H. Savajols, M. Laatiaoui, P. Chhetri, P. Mosat, Michael Block, J. C. Thomas, F. Giacoppo, O. Sorlin, S. Antalic, P. Wieczorek, J. Hoffmann, Alexander Yakushev, N. Kurz, S. Raeder, J. Khuyagbaatar, M. Vostinar, T. Murböck, Ch. E. Düllmann, F. P. Heßberger, O. Kamalou, Dieter Ackermann, F. Dechery, J. Piot, B. Andel, R.R. Mändl, J. Maurer, L. Caceres, Zhong Zhang, Ch. Stodel, C. Droese, A. K. Mistry, 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), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)
Subjects: Nuclear and High Energy Physics, [formula omitted], Ion beam, γ, α, Large volume Ge detectors, 7. Clean energy, 01 natural sciences, Signal, 99-00, Optics, 0103 physical sciences, Si strip detector, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010306 general physics, Spectroscopy, Instrumentation, CE and X-ray spectroscopy, Digital signal processing, Physics, 010308 nuclear & particles physics, business.industry, Detector, Digital electronics, 00-01, Chip, Filter (video), Granularity, business
Abstract: A compact silicon detector array with high spatial granularity and fast, fully digital data recording has been developed and commissioned for the investigation of heavy and superheavy nuclear species. The detector array can be combined in close geometry with large volume germanium detectors. It offers comprehensive particle and photon coincidence and correlation spectroscopy by highly efficient evaporation residue, α , γ , conversion electron and X-ray detection supported by the high granularity of the implantation chip. Access to fast decay events in the sub-microsecond region is made possible by the fast timing properties of the digital signal processing. A novel Si-chip support design allows direct cooling of the Si-chips and short signal transport. The compact and modular mechanical design equipped with a standard flange facilitates its transport and connection to different separators at different ion beam facilities. After initial tests, first α - γ coincidence spectroscopy experiments have been performed at the LISE separator of GANIL in Caen, France, in FULIS (velocity filter) mode and at the velocity filter SHIP of GSI in Darmstadt, Germany.
Published: 2018

31. Normal and intruder configurations in Si34 populated in the β− decay of Mg34 and Al34

Author: Ph. Dessagne, Alin Titus Serban, J. Mrazek, J. Pakarinen, V. F. E. Pucknell, O. Sorlin, F. Negoita, P. Morfouace, Carmen Gheorghe, P. Rahkila, E. Rapisarda, C. Sotty, J. Konki, C. Borcea, Olof Tengblad, S. Franchoo, A. N. Andreyev, Ph Morel, A. Turturica, Paul Greenlees, H. M. Lazarus, F. Nowacki, S. Kisyov, A. Poves, M. Stanoiu, R. Mărginean, S. Grévy, R. E. Mihai, L. M. Fraile, Cosmin Teodor Mihai, J. M. Daugas, Thierry Stora, A. Ionescu, A. Negret, M. J. G. Borge, N. Marginean, L. Stan, S. Calinescu, R. Lica, R. Borcea, C. Costache, H. De Witte, István Kuti, Marc Huyse, D. M. Filipescu, R. D. Page, M. Madurga, P. Van Duppen, N. Warr, and F. Rotaru
Subjects: Physics, 010308 nuclear & particles physics, Neutron emission, 0103 physical sciences, SHELL model, Nuclear structure, Atomic physics, 010306 general physics, Spectroscopy, 01 natural sciences
Abstract: The structure of $^{34}$Si was studied through $\gamma$ spectroscopy separately in the $\beta^-$ decays of $^{34}$Mg and $^{34}$Al at the ISOLDE facility of CERN. Different configurations in $^{34}$Si were populated independently from the two recently identified $\beta$-decaying states in $^{34}$Al having spin-parity assignments $J^\pi = 4^-$ dominated by the normal configuration $\pi (d_{5/2})^{-1} \otimes \nu (f_{7/2})$ and $J^\pi = 1^+$ by the intruder configuration $\pi (d_{5/2})^{-1} \otimes \nu (d_{3/2})^{-1}(f_{7/2})^{2}$. The paper reports on spectroscopic properties of $^{34}$Si such as an extended level scheme, spin and parity assignments based on log($ft$) values and $\gamma$-ray branching ratios, absolute $\beta$ feeding intensities and neutron emission probabilities. A total of 11 newly identified levels and 26 transitions were added to the previously known level scheme of $^{34}$Si. Large scale shell-model calculations using the {\sc sdpf-u-mix} interaction, able to treat higher order intruder configurations, are compared with the new results and conclusions are drawn concerning the predictive power of {\sc sdpf-u-mix}, the $N=20$ shell gap, the level of mixing between normal and intruder configurations for the 0$_1^+$, 0$_2^+$ and 2$_1^+$ states and the absence of triaxial deformation in $^{34}$Si.
Published: 2019

32. Soft breathing modes in neutron–rich nuclei with the subtracted second random–phase approximation

Author: D. Gambacurta, M. Grasso, O. Sorlin, 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)
Subjects: Physics, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Isoscalar, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, Nuclear structure, FOS: Physical sciences, Nuclear Structure, 7. Clean energy, 01 natural sciences, Asymmetry, Nuclear Theory (nucl-th), Dipole, Isospin, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Random phase approximation, Nuclear Experiment, Excitation, media_common
Abstract: We analyze the isoscalar response related to breathing modes with particular attention being paid to low-lying excitations in neutron-rich nuclei. We use the subtracted second random-phase approximation (SSRPA) to describe microscopically the response. By increasing the neutron excess, we study the evolution of the response in Ca isotopes going from $^{40}\mathrm{Ca}$ to $^{48}\mathrm{Ca}$ and to $^{60}\mathrm{Ca}$ as well as in $N=20$ isotones going from $^{40}\mathrm{Ca}$ to $^{36}\mathrm{S}$ and to $^{34}\mathrm{Si}$. Finally, the case of $^{68}\mathrm{Ni}$ is investigated. We predict soft monopole modes in neutron-rich nuclei which are driven by neutron excitations. At variance with dipole pygmy modes, these neutron excitations are not only strongly dominant at the surface of the nucleus but over its entire volume. The effect of the mixing with two particle--two hole configurations induced by the SSRPA model is analyzed. The properties of such soft neutron modes are investigated in terms of their excitation energies, transition densities and wave-function components. Their collectivity is also discussed as a function of the isospin asymmetry and of the mass of the nucleus. The link between such low-energy compression modes and a compressibility modulus introduced for neutron-rich infinite matter is finally studied.
Published: 2019

33. Quasi-free neutron and proton knockout reactions from light nuclei in a wide neutron-to-proton asymmetry range

Author: P. J. Woods, Matthias Heil, K. Boretzky, W. N. Catford, A. Henriques, M. Caamaño, Thomas Nilsson, J. Benlliure, P. Velho, Yasuhiro Togano, F. Wamers, I. Syndikus, E. Cravo, H. Alvarez-Pol, Joachim Enders, N. Kurz, O. Sorlin, Rituparna Kanungo, Deniz Savran, C. Nociforo, Mikhail V. Zhukov, L. M. Fraile, Marine Vandebrouck, Björn Jonson, M. Heine, Haik Simon, Roman Gernhäuser, Olof Tengblad, M. Holl, Z. Elekes, M. A. Najafi, Heiko Scheit, Carlos A. Bertulani, Kai Zuber, J. S. Winfield, T. Le Bleis, D. Cortina-Gil, L. Atar, Enrique Casarejos, Joakim Cederkäll, T. Kröll, C. Caesar, G. L. Wilson, G. Ribeiro, A. Kelic-Heil, Christoph Langer, Nasser Kalantar-Nayestanaki, Helmut Weick, Håkan T Johansson, Pavel Golubev, C. Wheldon, Thomas Aumann, Andreas Martin Heinz, Stefanos Paschalis, P. Díaz Fernández, D. M. Rossi, Enrique Nácher, Simon Lindberg, Catherine Rigollet, S. Beceiro-Novo, J. M. Boillos, L. V. Chulkov, Tanja Heftrich, V. Panin, D. Galaviz Redondo, Jorge Machado, Marina Petri, Rene Reifarth, Iris Dillmann, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), R3B, Federal Ministry of Education and Research (Germany), Technische Universität Darmstadt, Helmholtz International Center for FAIR, European Commission, Ministerio de Ciencia e Innovación (España), Ministerio de Economía, Industria y Competitividad (España), Swedish Research Council, National Science Foundation (US), Department of Energy (US), Fundação para a Ciência e a Tecnologia (Portugal), LIBPhys-UNL, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Nuclear and High Energy Physics, Proton, 3313 Tecnología E Ingeniería Mecánicas, media_common.quotation_subject, Nuclear Theory, Aucun, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Asymmetry, Nuclear physics, Momentum, Shell model, 0103 physical sciences, Neutron, ddc:530, 010306 general physics, Nuclear Experiment, Quasi-free scattering, media_common, Physics, Range (particle radiation), 010308 nuclear & particles physics, Scattering, 2207 Física Atómica y Nuclear, lcsh:QC1-999, Inverse kinematics, Isospin, Física nuclear, Spectroscopic factors, Beam (structure), lcsh:Physics
Abstract: 7 pags., 4 figs., 2 tabs. -- Open Access funded by Creative Commons Atribution Licence 4.0, The quasi-free scattering reactions C(p,2p) and C(p,pn) have been studied in inverse kinematics at beam energies of 300–400 MeV/u at the RB-LAND setup. The outgoing proton-proton and proton-neutron pairs were detected in coincidence with the reaction fragments in kinematically complete measurements. The efficiency to detect these pairs has been obtained from GEANT4 simulations which were tested using the C(p,2p) and C(p,pn) reactions. Experimental cross sections and momentum distributions have been obtained and compared to DWIA calculations based on eikonal theory. The new results reported here are combined with previously published cross sections for quasi-free scattering from oxygen and nitrogen isotopes and together they enable a systematic study of the reduction of single-particle strength compared to predictions of the shell model over a wide neutron-to-proton asymmetry range. The combined reduction factors show a weak or no dependence on isospin asymmetry, in contrast to the strong dependency reported in nucleon-removal reactions induced by nuclear targets at lower energies. However, the reduction factors for (p,2p) are found to be 'significantly smaller than for (p,pn) reactions for all investigated nuclei., This work was supported by the German Federal Ministry of Education and Research (BMBF projects 05P2015RDFN1 and 05P15WOFNA), through the GSI-TU Darmstadt cooperation agreement, by the State of Hesse through the LOEWE center HIC for FAIR, and the Helmholtz-Gemeinschaft through the graduate school HGS-HIRe. This work was supported by the European Union by means of the European Commission within its Seventh Framework Program (FP7) via ENSAR (Contract No. 262010), and the Spanish CICYT research grants FPA2012-32443, FPA2015-64969-07387, and FPA2015-69640-C2-1-P. This work has supported by the Swedish Research Council under contract number 621-2011-5324. C.A.B. acknowledges support from the U.S. NSF grant No. 1415656 and the U.S. DOE grant No. DE-FG02-08ER41533. Supported by the Portuguese FCT under the project PTDC/FIS/ 103902/2008.
Published: 2019

34. Reduced spin-orbit splitting in 35Si: Weak binding or density-depletion effect?

Author: F. de Oliveira Santos, J.P. Ebran, O. Sorlin, 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), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)
Subjects: Physics, Nuclear and High Energy Physics, Work (thermodynamics), [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Proton, 010308 nuclear & particles physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, lcsh:QC1-999, Amplitude, 0103 physical sciences, Covariant transformation, Neutron, Nuclide, Atomic physics, 010306 general physics, Parametrization, lcsh:Physics, Spin-½
Abstract: The reduction of the neutron spin-orbit (SO) splitting 2 p 3 / 2 − 2 p 1 / 2 between the 41Ca and 35Si isotones is a unique feature throughout the chart of nuclides, as the SO splitting usually increases with decreasing A. The way it is reduced, either gradually between 41Ca and 35Si or abruptly between 37S and 35Si, as well as the origin of its reduction, whether from the weak binding energy of the p states or from the sudden depletion in the central proton density moving to 35Si, are subject of debate. The results reported here using the self-consistent Covariant Energy Density Functional calculations with the DD-ME2 parametrization rather point to an abrupt, local decrease in 35Si, and to the large dominance of the central density depletion effect. It is concluded that weak binding, central density depletion as well as correlations must be taken into account to fully evaluate the amplitude and causes of this SO splitting reduction. To broaden the scope of the present work, discussions also include the recent experimental results of proton and neutron SO splittings around 132Sn and 56Ni.
Published: 2020

35. Encapsulated Sulfur targets for light ion beam experiments

Author: N. Y. Kheswa, Lucky Makhathini, M. Wiedeking, F. Nemulodi, Bongani Maqabuka, Sinegugu Mthembu, P. Papka, Sandile Jongile, A. Lemasson, Makuhane Sithole, O. Sorlin, Christiaan Brits, B. V. Kheswa, 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), 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: Materials science, Ion beam analysis, Ion beam, Proton, 010308 nuclear & particles physics, Physics, QC1-999, [PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph], Analytical chemistry, chemistry.chemical_element, 01 natural sciences, Sulfur, chemistry, Homogeneous, 0103 physical sciences, Irradiation, 010306 general physics, Deposition (law), Beam (structure)
Abstract: A new method was developed to produce enriched Sulfur targets with minimum loss of material. This was made possible by inserting Sulfur in-between two 0.5 μm Mylar foils (C10H8O4). The initial aim was to ensure that the Sulfur targets reduce by no more than 50% of the initial thickness within 24 hours under the equivalent of 10 J/cm2 of integrated energy deposition by an energetic (Eb > 50 MeV) proton beam. There is no loss of enriched material while making the target, as all the material is deposited within the surface area to be exposed to the beam. During beam irradiation, the targets were frequently swivelled in order to expose each part of the target to the beam and achieve homogeneous irradiation. Targets of 0.4 mg/cm2 thickness were produced and characterised using ion beam analysis technique with a 3 MeV proton beam.
Published: 2018

36. First Accurate Normalization of the β -delayed α Decay of N16 and Implications for the C12(α,γ)O16 Astrophysical Reaction Rate

Author: Oliver S. Kirsebom, H. De Witte, L. J. Harkness-Brennan, P. Rahkila, Jesper Hasseriis Mohr Jensen, P. Díaz Fernández, Esben Rohan Christensen, V. F. E. Pucknell, Ángel Perea, Björn Jonson, M. Munch, K. Riisager, P. Van Duppen, M.C. Gallardo, A. Negret, R. Mărginean, R. Lica, R. D. Page, María José García Borge, M. V. Lund, D.T. Doherty, O. Sorlin, T. Berry, N. Warr, Miguel Madurga, L. M. Fraile, H. Törnqvist, Paul Greenlees, J. A. Swartz, Andrei Andreyev, H. O. U. Fynbo, Olof Tengblad, N. Hubbard, I. Marroquin, C. Sotty, Håkan T Johansson, V. Vedia, Marc Huyse, D. S. Judson, H.B. Sørensen, C. Mihai, I.H. Lazarus, N. Marginean, and Joonas Konki
Subjects: Physics, Nuclear reaction, Nuclear physics, Reaction rate, Normalization (statistics), Light nucleus, 010308 nuclear & particles physics, Branching fraction, 0103 physical sciences, General Physics and Astronomy, Alpha decay, 010306 general physics, 01 natural sciences
Abstract: The C-12(alpha,gamma)O-16 reaction plays a central role in astrophysics, but its cross section at energies relevant for astrophysical applications is only poorly constrained by laboratory data. The reduced a width, gamma(11), of the bound 1(-) level in O-16 is particularly important to determine the cross section. The magnitude of gamma(11) is determined via sub-Coulomb a-transfer reactions or the beta-delayed a decay of N-16, but the latter approach is presently hampered by the lack of sufficiently precise data on the beta-decay branching ratios. Here we report improved branching ratios for the bound 1(-) level [b(beta,11) = (5.02 +/- 0.10) x 10(-2)] and for beta-delayed alpha emission [b(beta alpha) = (1.59 +/- 0.06) x 10(-5)]. Our value for b(beta alpha) is 33% larger than previously held, leading to a substantial increase in gamma(11). Our revised value for gamma(11) is in good agreement with the value obtained in a-transfer studies and the weighted average of the two gives a robust and precise determination of gamma(11), which provides significantly improved constraints on the C-12(alpha,gamma) cross section in the energy range relevant to hydrostatic He burning.
Published: 2018

37. Structure of Be13 studied in proton knockout from B14

Author: Roy Crawford Lemmon, C. Wimmer, U. Datta Pramanik, K. Goebel, I. Syndikus, Nasser Kalantar-Nayestanaki, C. Wheldon, Enrique Nácher, Thomas Aumann, J. S. Winfield, Andreas Martin Heinz, N. Kurz, L. M. Fraile, Hans Geissel, Rene Reifarth, Mikhail V. Zhukov, J. Marganiec, E. Cravo, P. Velho, M. Heine, M. Caamaño, M. Roeder, O. Ershova, Alfredo Estrade, Martin Freer, Daniel Bemmerer, G. L. Wilson, P. J. Woods, S. Pietri, Z. Elekes, G. Ribeiro, Björn Jonson, J. M. Boillos, Joakim Cederkäll, J. Taylor, J. Hagdahl, Herbert A. Simon, Paloma Diaz Fernandez, T. Kroell, Andreas Wagner, Matthias Heil, R. Crespo, A. Ignatov, M. J. G. Borge, K. Riisager, Roman Gernhaeuser, K. Boretzky, A. Movsesyan, Andreas Zilges, Carlos A. Bertulani, A. Hufnagel, H. O. U. Fynbo, A. Kelic-Heil, V. Panin, T. Le Bleis, Christoph Langer, D. Cortina-Gil, L. Atar, E. Casarejos, R. Thies, Jorge Machado, Joachim Enders, Olof Tengblad, Marina Petri, Ralf Plag, J. Benlliure, Deniz Savran, D. M. Rossi, Marielle Chartier, C. Caesar, Y. Aksyutina, Simon Lindberg, Catherine Rigollet, L. V. Chulkov, Daniel Galaviz, M. Holl, O. Sorlin, C. Nociforo, Helmut Weick, Håkan T Johansson, H. Scheit, W. N. Catford, Ángel Perea, Vladimir Avdeichikov, I. Dillmann, Pavel Golubev, F. Farinon, Stefanos Paschalis, H. Alvarez-Pol, R. Kanungo, Marine Vandebrouck, Kai Zuber, M. Labiche, A. Henriques, S. Beceiro-Novo, Thomas Nilsson, F. Wamers, and Tanja Heftrich
Subjects: Physics, Nuclear reaction, Proton, 010308 nuclear & particles physics, Nuclear Theory, Gamma ray, Halo nucleus, 01 natural sciences, Resonance (particle physics), Nuclear physics, Excited state, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: The neutron-unbound isotope Be-13 has been studied in several experiments using different reactions, different projectile energies, and different experimental setups. There is, however, no real consensus in the interpretation of the data, in particular concerning the structure of the low-lying excited states. Gathering new experimental information, which may reveal the Be-13 structure, is a challenge, particularly in light of its bridging role between Be-12, where the N = 8 neutron shell breaks down, and the Borromean halo nucleus Be-14. The purpose of the present study is to investigate the role of bound excited states in the reaction product Be-12 after proton knockout from B-14, by measuring coincidences between Be-12, neutrons, and gamma rays originating from de-excitation of states fed by neutron decay of Be-13. The Be-13 isotopes were produced in proton knockout from a 400 MeV/nucleon B-14 beam impinging on a CH2 target. The Be-12-n relative-energy spectrum d sigma/dE(fn) was obtained from coincidences between Be-12(g.s.) and a neutron, and also as threefold coincidences by adding gamma rays, from the de-excitation of excited states in Be-12. Neutron decay from the first 5/2(+) state in Be-13 to the 2(+) state in Be-12 at 2.11 MeV is confirmed. An energy independence of the proton-knockout mechanism is found from a comparison with data taken with a 35 MeV/nucleon B-14 beam. A low-lying p-wave resonance in Be-13(1/2(-)) is confirmed by comparing proton- and neutron-knockout data from B-14 and Be-14.
Published: 2018

38. Strong neutron pairing in core+4n nuclei

Author: S. Beceiro-Novo, R. Thies, Jorge Machado, Andreas Martin Heinz, Tanja Heftrich, L. M. Fraile, A. Estrade, Marina Petri, T. Le Bleis, D. Cortina-Gil, L. Atar, T. Kröll, A. Knyazev, M. A. Najafi, G. L. Wilson, D. Rossi, Kai Zuber, A. Movsesyan, Z. Elekes, Simon Lindberg, I. Syndikus, P. Díaz Fernández, K. Göbel, Catherine Rigollet, Ángel Perea, R. Crespo, F. Farinon, J. Kahlbow, V. Volkov, M. Caamaño, W. N. Catford, A. Ignatov, S. Pietri, Carlos A. Bertulani, V. Panin, C. Langer, A. Kelic-Heil, O. Sorlin, Stefanos Paschalis, J. M. Boillos, Enrique Casarejos, J. Hagdahl, Iris Dillmann, M Vandebrouck, O. Ershova, K. Boretzky, A. Henriques, Roy Crawford Lemmon, J. S. Winfield, J. Benlliure, M. Labiche, Vladimir Avdeichikov, Enrique Nácher, H. Weick, Thomas Nilsson, F. Wamers, Rituparna Kanungo, M. Holl, C. Caesar, P. Velho, Håkan T Johansson, G. Ribeiro, Pavel Golubev, F. M. Marqués, M. Heine, Andreas Zilges, Hans Geissel, J. Enders, D. Galaviz, Daniel Bemmerer, Deniz Savran, Marielle Chartier, María José García Borge, Haik Simon, M. Freer, J. Taylor, Nasser Kalantar-Nayestanaki, Olof Tengblad, C. Wheldon, C. Nociforo, A. Revel, H. Alvarez-Pol, Joakim Cederkäll, Thomas Aumann, Rene Reifarth, L. Chulkov, J. Marganiec, Mikhail V. Zhukov, D. Yakorev, Björn Jonson, M. Röder, Philip Woods, R. Plag, U. Datta Pramanik, Andreas Wagner, R. Gernhäuser, E. Cravo, Y. Togano, H. Scheit, N. Kurz, M. Heil, 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 ), Laboratoire de physique corpusculaire de Caen ( LPCC ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ) -Normandie Université ( NU ) -Ecole Nationale Supérieure d'Ingénieurs de Caen ( ENSICAEN ), Normandie Université ( NU ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien ( IPHC ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Strasbourg ( UNISTRA ), R3B, Technische Universität Darmstadt, Federal Ministry of Education and Research (Germany), National Science Foundation (US), Department of Energy (US), 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), 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)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-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), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Valence (chemistry), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Aucun, General Physics and Astronomy, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Molecular physics, Pairing, 0103 physical sciences, Neutron, Física nuclear, Nuclear Experiment (nucl-ex), [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, Nucleon, Nuclear Experiment, R3B radioactive beams nuclear structure neutron-rich Coulomb dissociation
Abstract: 6 pags., 4 figs., The emission of neutron pairs from the neutron-rich N = 12 isotones C-18 and O-20 has been studied by high-energy nucleon knockout from N-19 and O-21 secondary beams, populating unbound states of the two isotones up to 15 MeV above their two-neutron emission thresholds. The analysis of triple fragment-n-n correlations shows that the decay N-19(-1p)18C*-> C-16 + n + n is clearly dominated by direct pair emission. The two- neutron correlation strength, the largest ever observed, suggests the predominance of a C-14 core surrounded by four valence neutrons arranged in strongly correlated pairs. On the other hand, a significant competition of a sequential branch is found in the decay O-21(-1n)O-20*-> O-18 + n + n, attributed to its formation through the knockout of a deeply bound neutron that breaks the O-16 core and reduces the number of pairs., This work was supported by the German Federal Ministry for Education and Research (BMBF Project No. 05P15RDFN1), and through the GSI-TU Darmstadt cooperation agreement. C. A. Bertulani acknowledges support by U.S. Department of Energy Grant No. DE-FG02-08ER41533 and U.S. National Science Foundation Grant No. 1415656.
Published: 2018

39. Quasifree ( p,pN ) scattering of light neutron-rich nuclei near N=14

Author: Roy Crawford Lemmon, M. Röder, Rituparna Kanungo, P. Cabanelas, M. Heil, S. Pietri, Hans Geissel, E. Y. Nikolskii, A. Movsesyan, J. Marganiec, O. Ershova, J. Enders, N. Kurz, V. Volkov, K. Boretzky, Iris Dillmann, Stefanos Paschalis, H. Scheit, F. Farinon, A. Estrade, Vladimir Avdeichikov, R. Plag, G. L. Wilson, A. Najafi, L. M. Fraile, V. Panin, A. M. Moro, D. Jurčiukonis, Simon Lindberg, Catherine Rigollet, Kai Zuber, U. Datta Pramanik, A. Henriques, J. Benlliure, F. Wamers, D. Yakorev, Carlos A. Bertulani, María José García Borge, J. S. Winfield, C. Langer, Andreas Zilges, I. Syndikus, A. Kelic-Heil, A. Deltuva, Thomas Nilsson, T. Le Bleis, M. Heine, G. Ribeiro, E. Cravo, D. Cortina-Gil, L. Atar, Nasser Kalantar-Nayestanaki, Mikhail V. Zhukov, Daniel Bemmerer, C. Wheldon, Marine Vandebrouck, D. Galaviz, Thomas Aumann, Y. Togano, Andreas Martin Heinz, O. Sorlin, Björn Jonson, M. Holl, T. Kröll, Andreas Wagner, Joakim Cederkäll, S. Beceiro-Novo, Ángel Perea, Enrique Nácher, Z. Elekes, H. Weick, B. Fernández-Domínguez, Philip Woods, Håkan T Johansson, K. Göbel, R. Gernhäuser, B. Pietras, Deniz Savran, Pavel Golubev, Haik Simon, M. Freer, Olof Tengblad, Rene Reifarth, Tanja Heftrich, C. Nociforo, W. N. Catford, D. Rossi, H. Alvarez-Pol, A. Ignatov, L. Chulkov, C. Caesar, J. Taylor, P. Velho, R. Crespo, A. Knyazev, R. Thies, Jorge Machado, Marina Petri, J. M. Boillos, J. Hagdahl, A. Hufnagel, M. Labiche, P. Díaz Fernández, Marielle Chartier, M. Caamaño, and Enrique Casarejos
Subjects: Physics, Proton, Inverse kinematics, 010308 nuclear & particles physics, Scattering, Nuclear Theory, Inverse, 01 natural sciences, Light scattering, Nuclear physics, Momentum, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, Beam (structure)
Abstract: Background: For many years, quasifree scattering reactions in direct kinematics have been extensively used to study the structure of stable nuclei, demonstrating the potential of this approach. The (RB)-B-3 collaboration has performed a pilot experiment to study quasifree scattering reactions in inverse kinematics for a stable C-12 beam. The results from that experiment constitute the first quasifree scattering results in inverse and complete kinematics. This technique has lately been extended to exotic beams to investigate the evolution of shell structure, which has attracted much interest due to changes in shell structure if the number of protons or neutrons is varied. Purpose: In this work we investigate for the first time the quasifree scattering reactions (p, pn) and (p, 2p) simultaneously for the same projectile in inverse and complete kinematics for radioactive beams with the aim to study the evolution of single-particle properties from N = 14 to N = 15. Method: The structure of the projectiles O-23, O-22, and N-21 has been studied simultaneously via (p, pn) and (p, 2p) quasifree knockout reactions in complete inverse kinematics, allowing the investigation of proton and neutron structure at the same time. The experimental data were collected at the (RB)-B-3-LAND setup at GSI at beam energies of around 400 MeV/u. Two key observables have been studied to shed light on the structure of those nuclei: the inclusive cross sections and the corresponding momentum distributions. Conclusions: The knockout reactions (p, pn) and (p, 2p) with radioactive beams in inverse kinematics have provided important and complementary information for the study of shell evolution and structure. For the (p, pn) channels, indications of a change in the structure of these nuclei moving from N = 14 to N = 15 have been observed, i.e., from the 0d(5/2) shell to the 1s(1/2). This supports previous observations of a subshell closure at N = 14 for neutron-rich oxygen isotopes and its weakening for the nitrogen isotopes.
Published: 2018

40. Quasifree ( p , 2p ) Reactions on Oxygen Isotopes: Observation of Isospin Independence of the Reduced Single-Particle Strength

Author: Rene Reifarth, J. Kahlbow, E. Y. Nikolskii, R. Thies, Jorge Machado, M. Heine, A. Estrade, Marina Petri, G. Ribeiro, J. Taylor, Daniel Bemmerer, M. A. Najafi, Haik Simon, M. Freer, Olof Tengblad, Enrique Casarejos, H. Alvarez-Pol, Kai Zuber, F. Farinon, C. Nociforo, D. Rossi, Nasser Kalantar-Nayestanaki, C. Wheldon, Thomas Aumann, K. Boretzky, L. Chulkov, Andreas Martin Heinz, C. Caesar, Vladimir Avdeichikov, Tanja Heftrich, J. M. Boillos, J. Hagdahl, V. Panin, D. Galaviz Redondo, Ángel Perea, T. Kröll, Joakim Cederkäll, A. Ignatov, Carlos A. Bertulani, N. Kurz, A. Hufnagel, M. Labiche, S. Pietri, V. Volkov, P. Díaz Fernández, Mikhail V. Zhukov, G. L. Wilson, Simon Lindberg, Carlo Barbieri, I. Syndikus, J. Benlliure, F. Wamers, M. Heil, Marine Vandebrouck, Catherine Rigollet, M. Caamaño, Enrique Nácher, H. Weick, S. Beceiro-Novo, C. Langer, O. Ershova, A. Kelic-Heil, P. Velho, A. Henriques, J. S. Winfield, Thomas Nilsson, A. Knyazev, E. Cravo, Håkan T Johansson, R. Crespo, María José García Borge, Pavel Golubev, O. Sorlin, H. Scheit, Marielle Chartier, M. Holl, Deniz Savran, I. Dillmann, Stefanos Paschalis, D. Yakorev, Y. Togano, J. Marganiec-Gałązka, T. Le Bleis, D. Cortina-Gil, Rituparna Kanungo, Hans Geissel, L. Atar, A. Movsesyan, L. M. Fraile, Björn Jonson, Philip Woods, Andreas Wagner, R. Gernhäuser, Andreas Zilges, J. Enders, R. Lemmon, M. Röder, Z. Elekes, K. Göbel, R. Plag, and W. N. Catford
Subjects: Physics, Range (particle radiation), 010308 nuclear & particles physics, Eikonal equation, media_common.quotation_subject, Nuclear Theory, Ab initio, General Physics and Astronomy, chemistry.chemical_element, 7. Clean energy, 01 natural sciences, Asymmetry, Oxygen, Isotopes of oxygen, Nuclear physics, chemistry, Isospin, 0103 physical sciences, Particle, Nuclear Experiment, 010306 general physics, media_common
Abstract: Quasifree one-proton knockout reactions have been employed in inverse kinematics for a systematic study of the structure of stable and exotic oxygen isotopes at the R3B/LAND setup with incident beam energies in the range of 300-450 MeV/u. The oxygen isotopic chain offers a large variation of separation energies that allows for a quantitative understanding of single-particle strength with changing isospin asymmetry. Quasifree knockout reactions provide a complementary approach to intermediate-energy one-nucleon removal reactions. Inclusive cross sections for quasifree knockout reactions of the type OA(p,2p)NA-1 have been determined and compared to calculations based on the eikonal reaction theory. The reduction factors for the single-particle strength with respect to the independent-particle model were obtained and compared to state-of-the-art ab initio predictions. The results do not show any significant dependence on proton-neutron asymmetry.
Published: 2018

41. Neutron-rich nuclei produced at zero degrees in damped collisions induced by a beam of 18O on a 238U target

Author: A. Maj, C. Portail, F. Rotaru, B. Fornal, M. A. Naumenko, L. Olivier, F. de Oliveira Santos, S. Franchoo, A. Chbihi, P. Bednarczyk, A. V. Karpov, C. Petrone, Bertrand Jacquot, Oleg B. Tarasov, Ł. W. Iskra, Yu. E. Penionzhkevich, F. Azaiez, T. Lauritsen, D. Verney, M. Stanoiu, B. Szpak, F. C. L. Crespi, M. Maccormick, O. Sorlin, O. Kamalou, H. Savajols, I. Stefan, R. V. F. Janssens, I. Matea, N. Cieplicka-Oryńczak, M. Ciemala, Dieter Ackermann, Y. Blumenfeld, S. Leoni, Paola Marini, S. Calinescu, F. Hammache, M. Lewitowicz, S. M. Lukyanov, J. C. Thomas, 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), 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), 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 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)
Subjects: Physics, Nuclear reaction, Nuclear and High Energy Physics, Proton, 010308 nuclear & particles physics, Scattering, Projectile, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, lcsh:QC1-999, Momentum, Nuclear physics, Cross section (physics), Deep-inelastic collisions, 0103 physical sciences, Neutron, Nuclear reactions, 010306 general physics, Nuclear Experiment, Beam (structure), lcsh:Physics, Exotic nuclei
Abstract: Cross sections and corresponding momentum distributions have been measured for the first time at zero degrees for the exotic nuclei obtained from a beam of 18O at 8.5 MeV/A impinging on a 1 mg/cm2 238U target. Sizable cross sections were found for the production of exotic species arising from the neutron transfer and proton removal from the projectile. Comparisons of experimental results with calculations based on deep-inelastic reaction models, taking into account the particle evaporation process, indicate that zero degree is a scattering angle at which the differential reaction cross section for production of exotic nuclei is at its maximum. This result is important in view of the new generation of zero degrees spectrometers under construction, such as the S3 separator at GANIL, for example. Keywords: Nuclear reactions, Deep-inelastic collisions, Exotic nuclei
Published: 2018
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42. Evolution of shell structure in exotic nuclei

Author: Toshio Suzuki, O. Sorlin, Takaharu Otsuka, Yutaka Utsuno, Alexandra Gade, 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), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)
Subjects: Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], media_common.quotation_subject, Nuclear physics, General Physics and Astronomy, FOS: Physical sciences, 21.30.Fe, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Asymmetry, Nuclear Theory (nucl-th), 0103 physical sciences, Nuclear force, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Quantum, media_common, Physics, 21.10.-k, Isotope, 21.60.-n, 010308 nuclear & particles physics, Observable, Atomic nucleus, Nucleon
Abstract: The atomic nucleus is a quantum many-body system whose constituent nucleons (protons and neutrons) are subject to complex nucleon-nucleon interactions that include spin- and isospin-dependent components. For stable nuclei, already several decades ago, emerging seemingly regular patterns in some observables could be described successfully within a shell-model picture that results in particularly stable nuclei at certain magic fillings of the shells with protons and/or neutrons: N,Z = 8, 20, 28, 50, 82, 126. However, in short-lived, so-called exotic nuclei or rare isotopes, characterized by a large N/Z asymmetry and located far away from the valley of beta stability on the nuclear chart, these magic numbers, viewed through observables, were shown to change. These changes in the regime of exotic nuclei offer an unprecedented view at the roles of the various components of the nuclear force when theoretical descriptions are confronted with experimental data on exotic nuclei where certain effects are enhanced. This article reviews the driving forces behind shell evolution from a theoretical point of view and connects this to experimental signatures., Comment: 69 pages, 70 figures
Published: 2018
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43. Effective proton-neutron interaction near the drip line from unbound states in F25,26

Author: R. Crespo, Hans Geissel, Ralf Plag, J. Benlliure, Jason D. Holt, H. Hergert, Marine Vandebrouck, Christoph Langer, J. M. Boillos, Z. Elekes, J. Hagdahl, T. Kröll, J. Taylor, J. S. Winfield, A. Kelic-Heil, C. Caesar, Björn Jonson, Rene Reifarth, Roman Gernhäuser, A. Ignatov, D. M. Rossi, D. Galaviz, Joachim Enders, L. Chulkov, Deniz Savran, Ángel Perea, A. Lepailleur, F. Farinon, M. Heine, M. A. Najafi, Mikhail V. Zhukov, Nasser Kalantar-Nayestanaki, Andreas Wagner, T. Le Bleis, J. Kahlbow, Daniel Bemmerer, R. Kanungo, P. Velho, E. Y. Nikolskii, O. Sorlin, C. Wheldon, Thomas Aumann, M. Caamaño, D. Cortina-Gil, Stefanos Paschalis, Andreas Martin Heinz, L. Atar, Iris Dillmann, C. Nociforo, A. Henriques, R. Thies, Jorge Machado, O. Ershova, V. Panin, Marina Petri, Joakim Cederkäll, M. Holl, E. Cravo, Thomas Nilsson, A. Estrade, V. Volkov, W. N. Catford, Olof Tengblad, Vladimir Avdeichikov, Martin Freer, Marielle Chartier, F. Wamers, Simon Lindberg, M. J. G. Borge, Kai Zuber, Kathrin Göbel, Enrique Nácher, M. Röder, U. Datta Pramanik, Catherine Rigollet, H. Alvarez-Pol, Julien Gibelin, K. Boretzky, Yasuhiro Togano, M. Heil, I. Syndikus, L. M. Fraile, P. Díaz Fernández, A. Knyazev, S. R. Stroberg, S. Beceiro-Novo, Achim Schwenk, Tanja Heftrich, A. Movsesyan, D. Yakorev, A. Hufnagel, J. Marganiec, Helmut Weick, Håkan T Johansson, H. Scheit, Pavel Golubev, F. M. Marqués, Andreas Zilges, M. Labiche, G. L. Wilson, F. de Oliveira Santos, Carlos A. Bertulani, G. Ribeiro, P. J. Woods, S. Pietri, Enrique Casarejos, N. Kurz, Scott Bogner, Herbert A. Simon, and Roy Crawford Lemmon
Subjects: Physics, 010308 nuclear & particles physics, Binding energy, Ab initio, Resonance, 7. Clean energy, 01 natural sciences, Atomic mass, 0103 physical sciences, Bound state, Nuclear force, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Multiplet
Abstract: Background: Odd-odd nuclei, around doubly closed shells, have been extensively used to study proton-neutron interactions. However, the evolution of these interactions as a function of the binding energy, ultimately when nuclei become unbound, is poorly known. The F-26 nucleus, composed of a deeply bound pi 0d(5/2) proton and an unbound v0d(3/2) neutron on top of an O-24 core, is particularly adapted for this purpose. The coupling of this proton and neutron results in a J(pi) = 1(1)(+) - 4(1)(+) multiplet, whose energies must be determined to study the influence of the proximity of the continuum on the corresponding proton-neutron interaction. The J(pi) = 1(1)(+), 2(1)(+), 4(1)(+) bound states have been determined, and only a clear identification of the J(pi) = 3(1)(+) is missing. Purpose: We wish to complete the study of the J(pi) = 1(1)(+) - 4(1)(+) multiplet in F-26, by studying the energy and width of the J(pi) = 3(1)(+) unbound state. The method was first validated by the study of unbound states in F-25, for which resonances were already observed in a previous experiment. Method: Radioactive beams of Ne-26 and Ne-27, produced at about 440AMeV by the fragment separator at the GSI facility were used to populate unbound states in F-25 and F-26 via one-proton knockout reactions on a CH2 target, located at the object focal point of the (RB)-B-3/LAND setup. The detection of emitted. rays and neutrons, added to the reconstruction of the momentum vector of the A - 1 nuclei, allowed the determination of the energy of three unbound states in F-25 and two in F-26. Results: Based on its width and decay properties, the first unbound state in F-25, at the relative energy of 49(9) keV, is proposed to be a J(pi) = 1/ 2(-) arising from a p1/2 proton- hole state. In F-26, the first resonance at 323(33) keV is proposed to be the J(pi) = 3(1)(+) member of the J(pi) = 1(1)(+) - 4(1)(+) multiplet. Energies of observed states in F-25,F-26 have been compared to calculations using the independent-particle shell model, a phenomenological shell model, and the ab initio valence-space in-medium similarity renormalization group method. Conclusions: The deduced effective proton- neutron interaction is weakened by about 30-40% in comparison to the models, pointing to the need for implementing the role of the continuum in theoretical descriptions or to a wrong determination of the atomic mass of F-26.
Published: 2017

44. A proton density bubble in the doubly magic $^{34}$Si nucleus

Author: F. Rotaru, Kathrin Wimmer, Alexandra Gade, O. Sorlin, Daniel Bazin, C. Borcea, T. Roger, R. Borcea, Zsolt Dombrádi, J. P. Ebran, S. R. Stroberg, D. Weisshaar, A. Mutschler, M. Stanoiu, Elias Khan, A. Lepailleur, A. Lemasson, Dóra Sohler, F. Recchia, Marine Vandebrouck, H. Iwasaki, J. A. Tostevin, 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), 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), National Superconducting Cyclotron Laboratory (NSCL), Michigan State University [East Lansing], Michigan State University System-Michigan State University System, National Institut for Nuclear Physics and Engineering (IFIN HH), National Institut for Nuclear Physics and Engineering, Institute for Nuclear Research [Budapest] (ATOMKI), Hungarian Academy of Sciences (MTA), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Physics, University of Surrey, University of Surrey (UNIS), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)
Subjects: Proton, media_common.quotation_subject, Nuclear Theory, Nuclear physics, FOS: Physical sciences, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Asymmetry, 0103 physical sciences, medicine, Neutron, Nuclear Experiment (nucl-ex), Experimental nuclear physics, 010306 general physics, Nuclear Experiment, Quantum, media_common, Physics, 010308 nuclear & particles physics, medicine.anatomical_structure, Isospin, Atomic nucleus, Atomic physics, Electron scattering, Nucleus
Abstract: Many properties of the atomic nucleus, such as vibrations, rotations and incompressibility, can be interpreted as due to a two component quantum liquid of protons and neutrons. Electron scattering measurements on stable nuclei demonstrate that their central densities are saturated, as for liquid drops. In exotic nuclei near the limits of mass and charge, with large imbalances in their proton and neutron numbers, the possibility of a depleted central density, or a 'bubble' structure, has been discussed in a recurrent manner since the 1970s. Here we report first experimental evidence that points to a depletion of the central density of protons in the short-lived nucleus 34Si. The proton-to-neutron density asymmetry in 34Si offers the possibility to place constraints on the density and isospin dependence of the spin--orbit force-on which nuclear models have disagreed for decades-and on its stabilizing effect towards limits of nuclear existence., 6 pages, 3 figures
Published: 2017

45. Spectroscopy of Fe61 via the neutron transfer reaction H2(Fe60,p)Fe*61

Author: S. Giron, F. Hammache, N. de Séréville, P. Roussel, J. Burgunder, M. Moukaddam, D. Beaumel, L. Caceres, G. Duchêne, E. Clément, B. Fernandez-Dominguez, F. Flavigny, G. de France, S. Franchoo, D. Galaviz-Redondo, L. Gasques, J. Gibelin, A. Gillibert, S. Grevy, J. Guillot, M. Heil, J. Kiener, V. Lapoux, F. Maréchal, A. Matta, I. Matea, L. Nalpas, J. Pancin, L. Perrot, A. Obertelli, R. Raabe, J. A. Scarpaci, K. Sieja, O. Sorlin, I. Stefan, C. Stodel, M. Takechi, J. C. Thomas, and Y. Togano
Subjects: Physics, Photon, Silicon, 010308 nuclear & particles physics, chemistry.chemical_element, 01 natural sciences, 7. Clean energy, Charged particle, Cross section (physics), chemistry, 0103 physical sciences, Bound state, Neutron, Atomic physics, 010306 general physics, Adiabatic process, Spectroscopy
Abstract: The direct component of the 60Fe(n,γ)61Fe cross section was investigated by populating the bound states of the 61Fe nucleus through the (d,pγ) transfer reaction in inverse kinematics using a radioactive beam of 60Fe at 27A MeV. The experiment was performed at GANIL using the MUST2 array and an annular double-sided silicon strip detector for the detection of the light charged particle in coincidence with the photons measured in the EXOGAM γ-ray detectors. For the first time, the spectroscopic factors of the first 3/2−, 5/2−, 1/2−, and 9/2+ states of 61Fe were deduced experimentally from an adiabatic distorted wave approximation analysis of the data. The obtained results show a very good agreement with the shell-model predictions. The calculated direct component of the (n,γ) cross section was found negligible and of about 2% of the total, indicating a dominant resonant component.
Published: 2017

46. Determination of the neutron-capture rate of C17 for r -process nucleosynthesis

Author: Håkan T Johansson, Pavel Golubev, Enrique Casarejos, T. Adachi, J. Van de Walle, Ethan Uberseder, G. L. Wilson, Y. Aksyutina, S. Beceiro-Novo, J. Enders, Ángel Perea, F. Farinon, C. Langer, R. Knöbel, J. Benlliure, O. Lepyoshkina, Marielle Chartier, A. Kelic-Heil, F. Wamers, N. I. Ashwood, A. Najafi, M. Barr, Kai Zuber, J. Alcantara, Tanja Heftrich, T. Le Bleis, A. Henriques, G. Ickert, J. S. Winfield, D. Cortina-Gil, Thomas Nilsson, G. Ribeiro, Hans Geissel, S. Pietri, Haik Simon, M. Freer, Anisur Rahaman, C. Caesar, Olof Tengblad, C. Nociforo, Stefanos Paschalis, O. Ershova, D. Rossi, Y. Togano, Stefan Typel, S. Chakraborty, A. Movsesyan, O. Sorlin, K. Boretzky, K. Riisager, P. Díaz Fernández, Andreas Zilges, A. Ignatov, Meng-Ru Wu, P. Velho, Vladimir Avdeichikov, Simon Lindberg, A. Prochazka, Catherine Rigollet, Mario Weigand, M. Caamaño, B. Streicher, J. Taylor, Z. Elekes, W. N. Catford, S. Terashima, K. Göbel, V. Panin, Bo Jakobsson, M. Heil, J. Hagdahl, Carlos A. Bertulani, M. V. Ricciardi, Björn Jonson, Philip Woods, M. Labiche, M. Freudenberger, L. M. Fraile, R. Plag, U. Datta Pramanik, S. Altstadt, Gabriel Martínez-Pinedo, R. Thies, Jorge Machado, T. Neff, Marina Petri, R. Crespo, H. Weick, M. Holl, J. Kurcewicz, Andreas Wagner, H. Scheit, H. Alvarez-Pol, R. Gernhäuser, H. O. U. Fynbo, Nasser Kalantar-Nayestanaki, G. Rastrepina, J. Sanchez del Rio, D. Galaviz, C. Wheldon, Thomas Aumann, Deniz Savran, N. Kurz, Andreas Martin Heinz, M. Röder, T. Kröll, V. Stoica, M. Mostazo, V. Volkov, M. Heine, Daniel Bemmerer, I. Dillmann, Joakim Cederkäll, D. Yakorev, Mikhail V. Zhukov, V. Maroussov, A. Estrade, J. Marganiec, Rene Reifarth, G. Burgunder, Roy Crawford Lemmon, C. Wimmer, Rituparna Kanungo, L. Chulkov, R. Krücken, D. Gonzalez Diaz, and María José García Borge
Subjects: Physics, education.field_of_study, 010308 nuclear & particles physics, Population, 7. Clean energy, 01 natural sciences, Spectral line, Nuclear physics, Neutron capture, Nucleosynthesis, Excited state, 0103 physical sciences, Coulomb, r-process, Atomic physics, Nuclear Experiment, 010306 general physics, education, Ground state
Abstract: With the R$^{3}$B-LAND setup at GSI we have measured exclusive relative-energy spectra of the Coulomb dissociation of $^{18}$C at a projectile energy around 425~AMeV on a lead target, which are needed to determine the radiative neutron-capture cross sections of $^{17}$C into the ground state of $^{18}$C. Those data have been used to constrain theoretical calculations for transitions populating excited states in $^{18}$C. This allowed to derive the astrophysical cross section $\sigma^{*}_{\mathrm{n}\gamma}$ accounting for the thermal population of $^{17}$C target states in astrophysical scenarios. The experimentally verified capture rate is significantly lower than those of previously obtained Hauser-Feshbach estimations at temperatures $T_{9}\leq{}1$~GK. Network simulations with updated neutron-capture rates and hydrodynamics according to the neutrino-driven wind model as well as the neutron-star merger scenario reveal no pronounced influence of neutron capture of $^{17}$C on the production of second- and third-peak elements in contrast to earlier sensitivity studies.
Published: 2017

47. Fast neutron forward distributions from C, Be, and U thick targets bombarded by deuterons

Author: S. Ménard, M. Mirea, F. Clapier, N. Pauwels, J. Proust, C. Donzaud, D. Guillemaud-Mueller, I. Lhenry, A. C. Mueller, J. A. Scarpaci, and O. Sorlin
Subjects: Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: Measured angular and energetic distributions of neutrons obtained by bombarding Be, C, and U thick targets with ^{2}H at 17, 20, and 28 MeV incident energies are reported. The data were obtained using the time-of-flight method. The energetic distributions of neutrons were determined at 0°, 5°, 10°, and 20°. The data are compared with a modelization based on stripping formalism extended for thick targets.
Published: 1999
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48. Nearly degenerate isomeric states ofCu75

Author: M. Stanoiu, L. Gaudefroy, R. Borcea, O. Sorlin, O. Kamalou, C. Plaisir, S. Calinescu, F. Rotaru, C. Petrone, C. Borcea, T. Faul, G. Gey, J. C. Thomas, G. S. Simpson, L. Caceres, R. Chevrier, J. M. Daugas, F. Negoita, and G. Georgiev
Subjects: Physics, Valence (chemistry), 010308 nuclear & particles physics, 0103 physical sciences, Degenerate energy levels, Atomic physics, Nuclear Experiment, 010306 general physics, Spectroscopy, 01 natural sciences
Abstract: The decays of two isomeric states in the neutron-rich nucleus $^{75}\mathrm{Cu}$ have been studied via delayed $\ensuremath{\gamma}$-ray spectroscopy. These states were populated by the fragmentation of a $60.4\phantom{\rule{4pt}{0ex}}A\phantom{\rule{0.16em}{0ex}}\mathrm{MeV} ^{86}\mathrm{Kr}$ primary beam, which impinged on a Be target at the LISE2k spectrometer of GANIL. Isomeric half-lives and branching ratios were measured, and a $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coincidence analysis performed. These have allowed a revised level scheme of $^{75}\mathrm{Cu}$ to be proposed. A comparison with large-scale shell-model calculations using different effective interactions and valence spaces shows the importance of proton excitations across the $Z=28$ shell gap for reproducing the energy spacing between the isomeric states. The coexisting collective and single-particle properties of the $(1/{2}^{\ensuremath{-}})$ and $(3/{2}^{\ensuremath{-}})$ states, respectively, are similar to those of the same states in the neighboring $^{69,71,73}\mathrm{Cu}$. The small energy spacings between the $(1/{2}^{\ensuremath{-}}), (3/{2}^{\ensuremath{-}})$, and $5/{2}^{\ensuremath{-}}$ states are responsible for the isomerism.
Published: 2016

49. Coulomb dissociation of $^{20,21}$N

Author: A. Estrade, G. Burgunder, Andreas Martin Heinz, Andreas Wagner, Enrique Casarejos, Roy Crawford Lemmon, C. Wimmer, Ethan Uberseder, M. Heine, T. Le Bleis, N. Kurz, H. O. U. Fynbo, Olof Tengblad, D. Cortina-Gil, V. Stoica, F. Farinon, L. Atar, D. Yakorev, Joachim Enders, Helmut Weick, Z. Elekes, Carlos A. Bertulani, J. Sanchez del Rio Saez, Håkan T Johansson, Daniel Bemmerer, M. Freudenberger, D. Galaviz, Mikhail V. Zhukov, Heiko Scheit, Herbert A. Simon, A. Ignatov, P. Diaz-Fernandez, Nasser Kalantar-Nayestanaki, C. Wheldon, Thomas Aumann, P. Velho, J. Van de Walle, K. Riisager, Pavel Golubev, U. Datta Pramanik, J. Taylor, J. Marganiec, G. L. Wilson, Ralf Plag, J. Benlliure, O. Lepyoshkina, Marielle Chartier, N. I. Ashwood, A. Movsesyan, M. Röder, Andreas Zilges, Yasuhiro Togano, P. J. Woods, Ronja Thies, S. Pietri, R. Kanungo, Kai Zuber, Najafi, M. Labiche, M. J. G. Borge, Thomas Nilsson, A. Prochazka, G. Ribeiro, Christoph Langer, Ángel Perea, Roman Gernhäuser, G. Ickert, T. Adachi, R. Crespo, K. Boretzky, J. S. Winfield, W. N. Catford, G. Rastrepina, H. Alvarez-Pol, Bo Jakobsson, M. Barr, L. M. Fraile, C. Nociforo, F. Wamers, Rahaman, M. V. Ricciardi, M. Mostazo Caro, Björn Jonson, T. Kröll, Y. Aksyutina, Vladimir Avdeichikov, R. Knöbel, Matthias Heil, C. Caesar, B. Streicher, Joakim Cederkäll, J. Hagdahl, J. Kurcewicz, Deniz Savran, M. Caamaño, V. Volkov, Satoru Terashima, M. Holl, O. Ershova, Kathrin Göbel, A. Henriques, Martin Freer, J. Alcantara, Jorge Machado, Marina Petri, D. M. Rossi, Tanja Heftrich, S. Chakraborty, Mario Weigand, Simon Lindberg, R. Krücken, D. Gonzalez Diaz, Catherine Rigollet, Hans Geissel, Rene Reifarth, O. Sorlin, L. V. Chulkov, I. Dillmann, Stefanos Paschalis, V. Panin, S. Altstadt, S. Beceiro, A. Kelic-Heil, Helmholtz zentrum für Schwerionenforschung GmbH (GSI), 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), 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, Light nucleus, 010308 nuclear & particles physics, Thermonuclear reaction, Aucun, FOS: Physical sciences, chemistry.chemical_element, Detailed balance, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Dissociation (chemistry), Ion, chemistry, 0103 physical sciences, Coulomb, Fluorine, Nuclear Experiment (nucl-ex), Atomic physics, 010306 general physics, Nuclear Experiment, Excitation
Abstract: International audience; Neutron-rich light nuclei and their reactions play an important role for the creation of chemical elements. Here, data from a Coulomb dissociation experiment on $^{20,21}$N are reported. Relativistic $^{20,21}$N ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the $^{19}\mathrm{N}(\mathrm{n},\gamma)^{20}\mathrm{N}$ and $^{20}\mathrm{N}(\mathrm{n},\gamma)^{21}\mathrm{N}$ excitation functions and thermonuclear reaction rates have been determined. The $^{19}\mathrm{N}(\mathrm{n},\gamma)^{20}\mathrm{N}$ rate is up to a factor of 5 higher at $T
Published: 2016

50. Spectroscopy ofAr46by the(t,p)two-neutron transfer reaction

Author: J. Elseviers, Liam Gaffney, P. Reiter, R. Krücken, Riccardo Raabe, V. Bildstein, T. Kröll, M. Zielinska, Mark Huyse, J. Iwanicki, N. Warr, O. Sorlin, D. Mücher, R. Orlandi, T. Roger, H. De Witte, R. Lutter, G. Schrieder, Janne Pakarinen, K. Nowak, Kathrin Wimmer, Roman Gernhäuser, S. Hellgartner, P. Van Duppen, Joonas Konki, Jan Diriken, J. G. Johansen, and M. Seidlitz
Subjects: Physics, education.field_of_study, Large Hadron Collider, 010308 nuclear & particles physics, Population, 7. Clean energy, 01 natural sciences, Engineering physics, Recoil, Excited state, 0103 physical sciences, Physics::Accelerator Physics, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Spectroscopy, education, Excitation, Beam (structure)
Abstract: States in the N = 28 nucleus Ar-46 have been studied by a two-neutron transfer reaction at REX-ISOLDE (CERN). A beam of radioactive Ar-44 at an energy of 2.16 AMeV and a tritium-loaded titanium target were used to populate Ar-46 by the H-3(Ar-44, p) two-neutron transfer reaction. Protons emitted from the target were identified in the T-REX silicon detector array. The excitation energies of states in Ar-46 have been reconstructed from the measured angles and energies of recoil protons. Angular distributions for three final states were measured and based on the shape of the differential cross section an excited state at 3695 keV was identified as J(pi) = 0(+). The angular differential cross section for the population of different states are compared to calculations using a reaction model employing both sequential and direct transfer of two neutrons. Results are compared to shell-model calculations using state-of-the-art effective interactions.
Published: 2016

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