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1. Evolution of the two-neutron configuration from 11Li to 13Li

Author

P. André, A. Corsi, A. Revel, Y. Kubota, J. Casal, K. Fossez, J. Gómez-Camacho, G. Authelet, H. Baba, C. Caesar, D. Calvet, A. Delbart, M. Dozono, J. Feng, F. Flavigny, J.-M. Gheller, J. Gibelin, A. Giganon, A. Gillibert, K. Hasegawa, T. Isobe, Y. Kanaya, S. Kawakami, D. Kim, Y. Kiyokawa, M. Kobayashi, N. Kobayashi, T. Kobayashi, Y. Kondo, Z. Korkulu, S. Koyama, V. Lapoux, Y. Maeda, F.M. Marqués, T. Motobayashi, T. Miyazaki, T. Nakamura, N. Nakatsuka, Y. Nishio, A. Obertelli, A. Ohkura, N.A. Orr, S. Ota, H. Otsu, T. Ozaki, V. Panin, S. Paschalis, E.C. Pollacco, S. Reichert, J.-Y. Rousse, A.T. Saito, S. Sakaguchi, M. Sako, C. Santamaria, M. Sasano, H. Sato, M. Shikata, Y. Shimizu, Y. Shindo, L. Stuhl, T. Sumikama, Y.L. Sun, M. Tabata, Y. Togano, J. Tsubota, T. Uesaka, Z.H. Yang, J. Yasuda, K. Yoneda, and J. Zenihiro

Subjects
Quasi-free scattering, Three-body model, Dineutron decay, Physics, QC1-999
Abstract

In this work we investigate the two-neutron decay of 13Li and of the excited states of 11Li populated via one-proton removal from 14Be and 12Be, respectively. A phenomenological model is used to describe the decay of 11Li and 13Li. While the first one displays important sequential components, the second one appears dominated by the direct two-neutron decay. A microscopic three-body model is used to extract information on the spatial configuration of the emitted neutrons before the decay and shows that the average distance between the neutrons increases going from 11Li to 13Li.

Published
2024
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2. Spectroscopy of deeply bound orbitals in neutron-rich Ca isotopes

Author

P.J. Li, J. Lee, P. Doornenbal, S. Chen, S. Wang, A. Obertelli, Y. Chazono, J.D. Holt, B.S. Hu, K. Ogata, Y. Utsuno, K. Yoshida, N.L. Achouri, H. Baba, F. Browne, D. Calvet, F. Château, N. Chiga, A. Corsi, M.L. Cortés, A. Delbart, J.-M. Gheller, A. Giganon, A. Gillibert, C. Hilaire, T. Isobe, T. Kobayashi, Y. Kubota, V. Lapoux, H.N. Liu, T. Motobayashi, I. Murray, H. Otsu, V. Panin, N. Paul, W. Rodriguez, H. Sakurai, M. Sasano, D. Steppenbeck, L. Stuhl, Y.L. Sun, Y. Togano, T. Uesaka, K. Wimmer, K. Yoneda, O. Aktas, T. Aumann, K. Boretzky, C. Caesar, L.X. Chung, F. Flavigny, S. Franchoo, I. Gasparic, R.-B. Gerst, J. Gibelin, K.I. Hahn, J. Kahlbow, D. Kim, T. Koiwai, Y. Kondo, D. Körper, P. Koseoglou, C. Lehr, B.D. Linh, T. Lokotko, M. MacCormick, K. Miki, K. Moschner, T. Nakamura, S.Y. Park, D. Rossi, E. Sahin, F. Schindler, H. Simon, P.-A. Söderström, D. Sohler, S. Takeuchi, H. Toernqvist, J. Tscheuschner, V. Vaquero, V. Wagner, V. Werner, X. Xu, H. Yamada, D. Yan, Z. Yang, M. Yasuda, and L. Zanetti

Subjects
Unbound states, Knockout reaction, Single-particle strength, Shell evolution, Physics, QC1-999
Abstract

The calcium isotopes are an ideal system to investigate the evolution of shell structure and magic numbers. Although the properties of surface nucleons in calcium have been well studied, probing the structure of deeply bound nucleons remains a challenge. Here, we report on the first measurement of unbound states in 53Ca and 55Ca, populated from 54,56Ca(p,pn) reactions at a beam energy of around 216 MeV/nucleon at the RIKEN Radioactive Isotopes Beam Factory. The resonance properties, partial cross sections, and momentum distributions of these unbound states were analyzed. Orbital angular momentum l assignments were extracted from momentum distributions based on calculations using the distorted wave impulse approximation (DWIA) reaction model. The resonances at excitation energies of 5516(41)keV in 53Ca and 6000(250)keV in 55Ca indicate a significant l =3 component, providing the first experimental evidence for the ν0f7/2 single-particle strength of unbound hole states in the neutron-rich Ca isotopes. The observed excitation energies and cross-sections point towards extremely localized and well separated strength distributions, with some fragmentation for the ν0f7/2 orbital in 55Ca. These results are in good agreement with predictions from shell-model calculations using the effective GXPF1Bs interaction and ab initio calculations and diverge markedly from the experimental distributions in the nickel isotones at Z=28.

Published
2024
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3. 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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4. Shape coexistence in 66Se

Author

Z. Elekes, V. Panin, T.R. Rodríguez, K. Sieja, D.S. Ahn, A. Al-Adili, H. Baba, A.I. Stefanescu, K.J. Cook, Cs. Dósa, N. Fukuda, J. Gao, J. Gibelin, K.I. Hahn, Z. Halász, S.W. Huang, T. Isobe, M.M. Juhász, D. Kim, T. Kobayashi, Y. Kondo, Z. Korkulu, A. Kurihara, I. Kuti, H. Miki, K. Miki, T. Motobayashi, H. Otsu, A. Saastamoinen, M. Sasano, H. Sato, T. Shimada, Y. Shimizu, L.G. Sobotka, I. Stefanescu, L. Stuhl, H. Suzuki, H. Takeda, Y. Togano, T. Tomai, L. Trache, D. Tudor, T. Uesaka, Y. Utsuki, H. Wang, A. Yasuda, K. Yoneda, and Y. Yoshitome

Subjects
Neutron knock-out reaction, γ-ray spectroscopy, Nuclear structure, Shape coexistence, Physics, QC1-999
Abstract

The nuclear structure of 66Se, nucleus beyond the N=Z line on the proton-rich side of the valley of stability, was investigated by the neutron knock-out reaction 67Se(12C,X)66Se using a 12C target. The analysis of the singles spectrum of the γ-rays emitted during the de-excitation of the populated low-lying excited states revealed two previously detected (927(4) keV, 1460(32) keV) and three new (744(6) keV, 1210(17) keV, 1661(23) keV) transitions. The 744-keV, the 1210-keV, and the 1460-keV transitions were found to be in coincidence with the one at 927 keV. The spectrum coincident with the 927-keV transition showed a further possible transition at 299(35) keV, which was obscured by significant atomic background in the singles spectrum. This transition might correspond to a peak previously reported at 273(5) keV that could not be assigned to 66Se unambiguously. Based on a comparison of the experimental data to theoretical calculations, four new excited states are proposed which suggest that 66Se exhibits shape coexistence.

Published
2023
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5. Level structures of 56,58Ca cast doubt on a doubly magic 60Ca

Author

S. Chen, F. Browne, P. Doornenbal, J. Lee, A. Obertelli, Y. Tsunoda, T. Otsuka, Y. Chazono, G. Hagen, J.D. Holt, G.R. Jansen, K. Ogata, N. Shimizu, Y. Utsuno, K. Yoshida, N.L. Achouri, H. Baba, D. Calvet, F. Château, N. Chiga, A. Corsi, M.L. Cortés, A. Delbart, J.-M. Gheller, A. Giganon, A. Gillibert, C. Hilaire, T. Isobe, T. Kobayashi, Y. Kubota, V. Lapoux, H.N. Liu, T. Motobayashi, I. Murray, H. Otsu, V. Panin, N. Paul, W. Rodriguez, H. Sakurai, M. Sasano, D. Steppenbeck, L. Stuhl, Y.L. Sun, Y. Togano, T. Uesaka, K. Wimmer, K. Yoneda, O. Aktas, T. Aumann, L.X. Chung, F. Flavigny, S. Franchoo, I. Gasparic, R.-B. Gerst, J. Gibelin, K.I. Hahn, D. Kim, T. Koiwai, Y. Kondo, P. Koseoglou, C. Lehr, B.D. Linh, T. Lokotko, M. MacCormick, K. Moschner, T. Nakamura, S.Y. Park, D. Rossi, E. Sahin, P.-A. Söderström, D. Sohler, S. Takeuchi, H. Törnqvist, V. Vaquero, V. Wagner, S. Wang, V. Werner, X. Xu, H. Yamada, D. Yan, Z. Yang, M. Yasuda, and L. Zanetti

Subjects
Shell evolution, γ Ray spectroscopy, Physics, QC1-999
Abstract

Gamma decays were observed in 56Ca and 58Ca following quasi-free one-proton knockout reactions from 57,59Sc beams at ≈200 MeV/nucleon. For 56Ca, a γ ray transition was measured to be 1456(12) keV, while for 58Ca an indication for a transition was observed at 1115(34) keV. Both transitions were tentatively assigned as the 21+→0gs+ decays, and were compared to results from ab initio and conventional shell-model approaches. A shell-model calculation in a wide model space with a marginally modified effective nucleon-nucleon interaction depicts excellent agreement with experiment for 21+ level energies, two-neutron separation energies, and reaction cross sections, corroborating the formation of a new nuclear shell above the N = 34 shell. Its constituents, the 0f5/2 and 0g9/2 orbitals, are almost degenerate. This degeneracy precludes the possibility for a doubly magic 60Ca and potentially drives the dripline of Ca isotopes to 70Ca or even beyond.

Published
2023
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6. 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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7. Searching for universality of dineutron correlation at the surface of Borromean nuclei

Author

A. Corsi, Y. Kubota, J. Casal, M. Gómez-Ramos, A.M. Moro, G. Authelet, H. Baba, C. Caesar, D. Calvet, A. Delbart, M. Dozono, J. Feng, F. Flavigny, J.-M. Gheller, J. Gibelin, A. Giganon, A. Gillibert, K. Hasegawa, T. Isobe, Y. Kanaya, S. Kawakami, D. Kim, Y. Kiyokawa, M. Kobayashi, N. Kobayashi, T. Kobayashi, Y. Kondo, Z. Korkulu, S. Koyama, V. Lapoux, Y. Maeda, F.M. Marqués, T. Motobayashi, T. Miyazaki, T. Nakamura, N. Nakatsuka, Y. Nishio, A. Obertelli, A. Ohkura, N.A. Orr, S. Ota, H. Otsu, T. Ozaki, V. Panin, S. Paschalis, E.C. Pollacco, S. Reichert, J.-Y. Rousse, A.T. Saito, S. Sakaguchi, M. Sako, C. Santamaria, M. Sasano, H. Sato, M. Shikata, Y. Shimizu, Y. Shindo, L. Stuhl, T. Sumikama, Y.L. Sun, M. Tabata, Y. Togano, J. Tsubota, T. Uesaka, Z.H. Yang, J. Yasuda, K. Yoneda, and J. Zenihiro

Subjects
Quasi-free scattering, Borromean nuclei, Three-body model, Jacobi coordinates, Dineutron, Physics, QC1-999
Abstract

The dineutron correlation is systematically studied in three different Borromean nuclei near the neutron dripline, 11Li, 14Be and 17B, via the (p,pn) knockout reaction measured at the RIBF facility in RIKEN. For the three nuclei, the correlation angle between the valence neutrons is found to be largest in the same range of intrinsic momenta, which can be associated to the nuclear surface. This result reinforces the prediction that the formation of the dineutron is universal in environments with low neutron density, such as the surface of neutron-rich Borromean nuclei.

Published
2023
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8. Unbound states in 17C and p-sd shell-model interactions

Author

S. Kim, J.W. Hwang, Y. Satou, N.A. Orr, T. Nakamura, Y. Kondo, J. Gibelin, N.L. Achouri, T. Aumann, H. Baba, F. Delaunay, P. Doornenbal, N. Fukuda, N. Inabe, T. Isobe, D. Kameda, D. Kanno, N. Kobayashi, T. Kobayashi, T. Kubo, S. Leblond, J. Lee, F.M. Marqués, R. Minakata, T. Motobayashi, D. Murai, T. Murakami, K. Muto, T. Nakashima, N. Nakatsuka, A. Navin, S. Nishi, S. Ogoshi, H. Otsu, H. Sato, Y. Shimizu, H. Suzuki, K. Takahashi, H. Takeda, S. Takeuchi, R. Tanaka, Y. Togano, A.G. Tuff, M. Vandebrouck, and K. Yoneda

Subjects
One-neutron removal reaction, Neutron-rich carbon isotopes, Cross-shell states, Shell-model Hamiltonian, Physics, QC1-999
Abstract

Unbound states in C17 were investigated via one-neutron removal from a C18 beam at an energy of 245 MeV/nucleon on a carbon target. The energy spectrum of C17, above the single-neutron decay threshold, was reconstructed using invariant mass spectroscopy from the measured momenta of the C16 fragment and neutron, and was found to exhibit resonances at Er=0.52(2), 0.77(2), 1.36(1), 1.91(1), 2.22(3) and 3.20(1) MeV. The resonance at Er=0.77(2) MeV [Ex=1.51(3) MeV] was provisionally assigned as the second 5/2+ state. The two resonances at Er=1.91(1) and 3.20(1) MeV [Ex=2.65(2) and 3.94(2) MeV] were identified, through comparison of the energies, cross sections and momentum distributions with shell-model and eikonal reaction calculations, as p-shell hole states with spin-parities 1/21− and 3/21−, respectively. A detailed comparison was made with the results obtained using a range of shell-model interactions. The YSOX shell-model Hamiltonian, the cross-shell part of which is based on the monopole-based universal interaction, was found to provide a very good description of the present results and those for the neighbouring odd-A carbon isotopes – in particular for the negative parity cross-shell states.

Published
2023
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9. 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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10. Experimental investigation of ground-state properties of 7H with transfer reactions

Author

M. Caamaño, T. Roger, A.M. Moro, G.F. Grinyer, J. Pancin, S. Bagchi, S. Sambi, J. Gibelin, B. Fernández–Domínguez, N. Itagaki, J. Benlliure, D. Cortina–Gil, F. Farget, B. Jacquot, D. Pérez–Loureiro, B. Pietras, R. Raabe, D. Ramos, C. Rodríguez Tajes, H. Savajols, and M. Vandebrouck

Subjects
7H, Hydrogen resonance, Active target, Physics, QC1-999
Abstract

The properties of nuclei with extreme neutron–to–proton ratios, far from those naturally occurring on Earth, are key to understand nuclear forces and how nucleons hold together to form nuclei. 7H, with six neutrons and a single proton, is the nuclear system with the most unbalanced neutron–to–proton ratio known so far. However, its sheer existence and properties are still a challenge for experimental efforts and theoretical models. Here we report experimental evidences on the formation of 7H as a resonance, detected with independent observables, and the first measurement of the structure of its ground state. The resonance is found at ∼0.7 MeV above the 3H+4n mass, with a narrow width of ∼0.2 MeV and a 1/2+ spin and parity. These data are consistent with a 7H as a 3H core surrounded by an extended four-neutron halo, with a unique four-neutron decay and a relatively long half-life thanks to neutron pairing; a prime example of new phenomena occurring in what would be the most pure-neutron nuclear matter we can access in the laboratory.

Published
2022
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11. A first glimpse at the shell structure beyond 54Ca: Spectroscopy of 55K, 55Ca, and 57Ca

Author

T. Koiwai, K. Wimmer, P. Doornenbal, A. Obertelli, C. Barbieri, T. Duguet, J.D. Holt, T. Miyagi, P. Navrátil, K. Ogata, N. Shimizu, V. Somà, Y. Utsuno, K. Yoshida, N.L. Achouri, H. Baba, F. Browne, D. Calvet, F. Château, S. Chen, N. Chiga, A. Corsi, M.L. Cortés, A. Delbart, J.-M. Gheller, A. Giganon, A. Gillibert, C. Hilaire, T. Isobe, T. Kobayashi, Y. Kubota, V. Lapoux, H.N. Liu, T. Motobayashi, I. Murray, H. Otsu, V. Panin, N. Paul, W. Rodriguez, H. Sakurai, M. Sasano, D. Steppenbeck, L. Stuhl, Y.L. Sun, Y. Togano, T. Uesaka, K. Yoneda, O. Aktas, T. Aumann, L.X. Chung, F. Flavigny, S. Franchoo, I. Gasparic, R.-B. Gerst, J. Gibelin, K.I. Hahn, D. Kim, Y. Kondo, P. Koseoglou, J. Lee, C. Lehr, B.D. Linh, T. Lokotko, M. MacCormick, K. Moschner, T. Nakamura, S.Y. Park, D. Rossi, E. Sahin, P.-A. Söderström, D. Sohler, S. Takeuchi, H. Toernqvist, V. Vaquero, V. Wagner, S. Wang, V. Werner, X. Xu, H. Yamada, D. Yan, Z. Yang, M. Yasuda, and L. Zanetti

Subjects
Radioactive beams, γ-ray spectroscopy, Shell evolution, Physics, QC1-999
Abstract

States in the N=35 and 37 isotopes 55,57Ca have been populated by direct proton-induced nucleon removal reactions from 56,58Sc and 56Ca beams at the RIBF. In addition, the (p,2p) quasi-free single-proton removal reaction from 56Ca was studied. Excited states in 55K, 55Ca, and 57Ca were established for the first time via in-beam γ-ray spectroscopy. Results for the proton and neutron removal reactions from 56Ca to states in 55K and 55Ca for the level energies, excited state lifetimes, and exclusive cross sections agree well with state-of-the-art theoretical calculations using different approaches. The observation of a short-lived state in 57Ca suggests a transition in the calcium isotopic chain from single-particle dominated states at N=35 to collective excitations at N=37.

Published
2022
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12. First spectroscopic study of 51Ar by the (p,2p) reaction

Author

M.M. Juhász, Z. Elekes, D. Sohler, Y. Utsuno, K. Yoshida, T. Otsuka, K. Ogata, P. Doornenbal, A. Obertelli, H. Baba, F. Browne, D. Calvet, F. Château, S. Chen, N. Chiga, A. Corsi, M.L. Cortés, A. Delbart, J.-M. Gheller, A. Giganon, A. Gillibert, C. Hilaire, T. Isobe, T. Kobayashi, Y. Kubota, V. Lapoux, T. Motobayashi, I. Murray, H. Otsu, V. Panin, N. Paul, W. Rodriguez, H. Sakurai, M. Sasano, D. Steppenbeck, L. Stuhl, Y.L. Sun, Y. Togano, T. Uesaka, K. Wimmer, K. Yoneda, N.L. Achouri, O. Aktas, T. Aumann, L.X. Chung, Zs. Dombrádi, F. Flavigny, S. Franchoo, I. Gašparić, R.-B. Gerst, J. Gibelin, K.I. Hahn, D. Kim, T. Koiwai, Y. Kondo, P. Koseoglou, J. Lee, C. Lehr, B.D. Linh, H.N. Liu, T. Lokotko, M. MacCormick, K. Moschner, T. Nakamura, S.Y. Park, D. Rossi, E. Sahin, P.-A. Söderström, S. Takeuchi, H. Törnqvist, V. Vaquero, V. Wagner, S. Wang, V. Werner, X. Xu, H. Yamada, D. Yan, Z. Yang, M. Yasuda, and L. Zanetti

Subjects
Proton knock-out reaction, γ-ray spectroscopy, Invariant mass method, Nuclear structure, Shell closure, Physics, QC1-999
Abstract

The nuclear structure of 51Ar, an uncharted territory so far, was studied by the (p,2p) reaction using γ-ray spectroscopy for the bound states and the invariant mass method for the unbound states. Two peaks were detected in the γ-ray spectrum and six peaks were observed in the 50Ar+n relative energy spectrum. Comparing the results to our shell-model calculations, two bound and six unbound states were established. Three of the unbound states could only be placed tentatively due to the low number of counts in the relative energy spectrum of events associated with the decay through the first excited state of 50Ar. The low cross sections populating the two bound states of 51Ar could be interpreted as a clear signature for the presence of significant subshell closures at neutron numbers 32 and 34 in argon isotopes. It was also revealed that due to the two valence holes, unbound collective states coexist with individual-particle states in 51Ar.

Published
2021
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13. 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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14. Restoration of the natural E(1/21+) - E(3/21+) energy splitting in odd-K isotopes towards N = 40

Author

Y.L. Sun, A. Obertelli, P. Doornenbal, C. Barbieri, Y. Chazono, T. Duguet, H.N. Liu, P. Navrátil, F. Nowacki, K. Ogata, T. Otsuka, F. Raimondi, V. Somà, Y. Utsuno, K. Yoshida, N. Achouri, H. Baba, F. Browne, D. Calvet, F. Château, S. Chen, N. Chiga, A. Corsi, M.L. Cortés, A. Delbart, J.-M. Gheller, A. Giganon, A. Gillibert, C. Hilaire, T. Isobe, T. Kobayashi, Y. Kubota, V. Lapoux, T. Motobayashi, I. Murray, H. Otsu, V. Panin, N. Paul, W. Rodriguez, H. Sakurai, M. Sasano, D. Steppenbeck, L. Stuhl, Y. Togano, T. Uesaka, K. Wimmer, K. Yoneda, O. Aktas, T. Aumann, L.X. Chung, F. Flavigny, S. Franchoo, I. Gašparić, R.-B. Gerst, J. Gibelin, K.I. Hahn, D. Kim, T. Koiwai, Y. Kondo, P. Koseoglou, J. Lee, C. Lehr, B.D. Linh, T. Lokotko, M. MacCormick, K. Moschner, T. Nakamura, S.Y. Park, D. Rossi, E. Sahin, D. Sohler, P.-A. Söderström, S. Takeuchi, H. Törnqvist, V. Vaquero, V. Wagner, S. Wang, V. Werner, X. Xu, H. Yamada, D. Yan, Z. Yang, M. Yasuda, and L. Zanetti

Subjects
Physics, QC1-999
Abstract

We report on the first γ-ray spectroscopy of 51,53K produced via the 52,54Ca(p,2p) reactions at ∼250 MeV/nucleon. Unambiguous final-state angular-momentum assignments were achieved for beam intensities down to few particles per second by using a new technique based on reaction vertex tracking combined with a thick liquid-hydrogen target. Through γ-ray spectroscopy and exclusive parallel momentum distribution analysis, 3/2+ ground states and 1/2+ first excited states in 51,53K were established quantifying the natural ordering of the 1d3/2 and 2s1/2 proton-hole states that are restored at N = 32 and 34. State-of-the-art ab initio calculations and shell-model calculations with improved phenomenological effective interactions reproduce the present data and predict consistently the increase of the E(1/21+) - E(3/21+) energy differences towards N = 40. Keywords: Spectroscopy, Shell evolution, 51K, 53K

Published
2020
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15. Shell evolution of N = 40 isotones towards 60Ca: First spectroscopy of 62Ti

Author

M.L. Cortés, W. Rodriguez, P. Doornenbal, A. Obertelli, J.D. Holt, S.M. Lenzi, J. Menéndez, F. Nowacki, K. Ogata, A. Poves, T.R. Rodríguez, A. Schwenk, J. Simonis, S.R. Stroberg, K. Yoshida, L. Achouri, H. Baba, F. Browne, D. Calvet, F. Château, S. Chen, N. Chiga, A. Corsi, A. Delbart, J.-M. Gheller, A. Giganon, A. Gillibert, C. Hilaire, T. Isobe, T. Kobayashi, Y. Kubota, V. Lapoux, H.N. Liu, T. Motobayashi, I. Murray, H. Otsu, V. Panin, N. Paul, H. Sakurai, M. Sasano, D. Steppenbeck, L. Stuhl, Y.L. Sun, Y. Togano, T. Uesaka, K. Wimmer, K. Yoneda, O. Aktas, T. Aumann, L.X. Chung, F. Flavigny, S. Franchoo, I. Gašparić, R.-B. Gerst, J. Gibelin, K.I. Hahn, D. Kim, T. Koiwai, Y. Kondo, P. Koseoglou, J. Lee, C. Lehr, B.D. Linh, T. Lokotko, M. MacCormick, K. Moschner, T. Nakamura, S.Y. Park, D. Rossi, E. Sahin, D. Sohler, P.-A. Söderström, S. Takeuchi, H. Toernqvist, V. Vaquero, V. Wagner, S. Wang, V. Werner, X. Xu, H. Yamada, D. Yan, Z. Yang, M. Yasuda, and L. Zanetti

Subjects
Physics, QC1-999
Abstract

Excited states in the N=40 isotone 62Ti were populated via the 63V(p,2p)62Ti reaction at ∼200 MeV/nucleon at the Radioactive Isotope Beam Factory and studied using γ-ray spectroscopy. The energies of the 21+→0gs+ and 41+→21+ transitions, observed here for the first time, indicate a deformed 62Ti ground state. These energies are increased compared to the neighboring 64Cr and 66Fe isotones, suggesting a small decrease of quadrupole collectivity. The present measurement is well reproduced by large-scale shell-model calculations based on effective interactions, while ab initio and beyond mean-field calculations do not yet reproduce our findings. The shell-model calculations for 62Ti show a dominant configuration with four neutrons excited across the N=40 gap. Likewise, they indicate that the N=40 island of inversion extends down to Z=20, disfavoring a possible doubly magic character of the elusive 60Ca. Keywords: Shell evolution, Radioactive beams, Gamma-ray spectroscopy

Published
2020
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16. Single-neutron knockout from 20C and the structure of 19C

Author

J.W. Hwang, S. Kim, Y. Satou, N.A. Orr, Y. Kondo, T. Nakamura, J. Gibelin, N.L. Achouri, T. Aumann, H. Baba, F. Delaunay, P. Doornenbal, N. Fukuda, N. Inabe, T. Isobe, D. Kameda, D. Kanno, N. Kobayashi, T. Kobayashi, T. Kubo, S. Leblond, J. Lee, F.M. Marqués, R. Minakata, T. Motobayashi, D. Murai, T. Murakami, K. Muto, T. Nakashima, N. Nakatsuka, A. Navin, S. Nishi, S. Ogoshi, H. Otsu, H. Sato, Y. Shimizu, H. Suzuki, K. Takahashi, H. Takeda, S. Takeuchi, R. Tanaka, Y. Togano, A.G. Tuff, M. Vandebrouck, and K. Yoneda

Subjects
Heavy-ion knockout, Invariant mass spectroscopy, Shell evolution, Physics, QC1-999
Abstract

The low-lying unbound level structure of the halo nucleus 19C has been investigated using single-neutron knockout from 20C on a carbon target at 280 MeV/nucleon. The invariant mass spectrum, derived from the momenta of the forward going beam velocity 18C fragment and neutrons, was found to be dominated by a very narrow near threshold (Erel=0.036(1) MeV) peak. Two less strongly populated resonance-like features were also observed at Erel=0.84(4) and 2.31(3) MeV, both of which exhibit characteristics consistent with neutron p-shell hole states. Comparisons of the energies, measured cross sections and parallel momentum distributions to the results of shell-model and eikonal reaction calculations lead to spin-parity assignments of 5/21+ and 1/21− for the levels at Ex=0.62(9) and 2.89(10) MeV with Sn=0.58(9) MeV. Spectroscopic factors were also deduced and found to be in reasonable accord with shell-model calculations. The valence neutron configuration of the 20C ground state is thus seen to include, in addition to the known 1s1/22 component, a significant 0d5/22 contribution. The level scheme of 19C, including significantly the 1/21− cross-shell state, is well accounted for by the YSOX shell-model interaction developed from the monopole-based universal interaction.

Published
2017
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17. Structure of 13Be probed via quasi-free scattering

Author

A. Corsi, Y. Kubota, J. Casal, M. Gómez-Ramos, A.M. Moro, G. Authelet, H. Baba, C. Caesar, D. Calvet, A. Delbart, M. Dozono, J. Feng, F. Flavigny, J.-M. Gheller, J. Gibelin, A. Giganon, A. Gillibert, K. Hasegawa, T. Isobe, Y. Kanaya, S. Kawakami, D. Kim, Y. Kiyokawa, M. Kobayashi, N. Kobayashi, T. Kobayashi, Y. Kondo, Z. Korkulu, S. Koyama, V. Lapoux, Y. Maeda, F.M. Marqués, T. Motobayashi, T. Miyazaki, T. Nakamura, N. Nakatsuka, Y. Nishio, A. Obertelli, A. Ohkura, N.A. Orr, S. Ota, H. Otsu, T. Ozaki, V. Panin, S. Paschalis, E.C. Pollacco, S. Reichert, J.-Y. Rousse, A.T. Saito, S. Sakaguchi, M. Sako, C. Santamaria, M. Sasano, H. Sato, M. Shikata, Y. Shimizu, Y. Shindo, L. Stuhl, T. Sumikama, Y.L. Sun, M. Tabata, Y. Togano, J. Tsubota, T. Uesaka, Z.H. Yang, J. Yasuda, K. Yoneda, and J. Zenihiro

Subjects
Physics, QC1-999
Abstract

We present an investigation of the structure of 13Be obtained via a kinematically complete measurement of the (p,pn) reaction in inverse kinematics at 265 MeV/nucleon. The relative energy spectrum of 13Be is compared to Transfer-to-the-Continuum calculations which use as structure inputs the overlaps of the 14Be ground-state wave function, computed in a three-body model, with the unbound states of the 13Be residual nucleus. The key role of neutron p-wave orbital in the interpretation of the low-relative-energy part of the spectrum is discussed. Keywords: Quasi-free scattering, Borromean nuclei, Three-body model, Resonances

Published
2019
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18. Interaction cross section study of the two-neutron halo nucleus 22C

Author

Y. Togano, T. Nakamura, Y. Kondo, J.A. Tostevin, A.T. Saito, J. Gibelin, N.A. Orr, N.L. Achouri, T. Aumann, H. Baba, F. Delaunay, P. Doornenbal, N. Fukuda, J.W. Hwang, N. Inabe, T. Isobe, D. Kameda, D. Kanno, S. Kim, N. Kobayashi, T. Kobayashi, T. Kubo, S. Leblond, J. Lee, F.M. Marqués, R. Minakata, T. Motobayashi, D. Murai, T. Murakami, K. Muto, T. Nakashima, N. Nakatsuka, A. Navin, S. Nishi, S. Ogoshi, H. Otsu, H. Sato, Y. Satou, Y. Shimizu, H. Suzuki, K. Takahashi, H. Takeda, S. Takeuchi, R. Tanaka, A.G. Tuff, M. Vandebrouck, and K. Yoneda

Subjects
Interaction cross section, Matter radius, Two-neutron halo nucleus 22C, Physics, QC1-999
Abstract

The interaction cross sections (σI) of the very neutron-rich carbon isotopes 19C, 20C and 22C have been measured on a carbon target at 307, 280, and 235 MeV/nucleon, respectively. A σI of 1.280±0.023 b was obtained for 22C, significantly larger than for 19,20C, supporting the halo character of 22C. A 22C root-mean-squared matter radius of 3.44±0.08 fm was deduced using a four-body Glauber reaction model. This value is smaller than an earlier estimate (of 5.4±0.9 fm) derived from a σI measurement on a hydrogen target at 40 MeV/nucleon. These new, higher-precision σI data provide stronger constraints for assessing the consistency of theories describing weakly bound nuclei.

Published
2016
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19. Observation of isoscalar multipole strengths in exotic doubly-magic 56Ni in inelastic α scattering in inverse kinematics

Author

S. Bagchi, J. Gibelin, M.N. Harakeh, N. Kalantar-Nayestanaki, N.L. Achouri, H. Akimune, B. Bastin, K. Boretzky, H. Bouzomita, M. Caamaño, L. Càceres, S. Damoy, F. Delaunay, B. Fernández-Domínguez, M. Fujiwara, U. Garg, G.F. Grinyer, O. Kamalou, E. Khan, A. Krasznahorkay, G. Lhoutellier, J.F. Libin, S. Lukyanov, K. Mazurek, M.A. Najafi, J. Pancin, Y. Penionzhkevich, L. Perrot, R. Raabe, C. Rigollet, T. Roger, S. Sambi, H. Savajols, M. Senoville, C. Stodel, L. Suen, J.C. Thomas, M. Vandebrouck, and J. Van de Walle

Subjects
Physics, QC1-999
Abstract

The Isoscalar Giant Monopole Resonance (ISGMR) and the Isoscalar Giant Dipole Resonance (ISGDR) compression modes have been studied in the doubly-magic unstable nucleus 56Ni. They were measured by inelastic α-particle scattering in inverse kinematics at 50 MeV/u with the MAYA active target at the GANIL facility. The centroid of the ISGMR has been obtained at Ex=19.1±0.5 MeV. Evidence for the low-lying part of the ISGDR has been found at Ex=17.4±0.7 MeV. The strength distribution for the dipole mode shows similarity with the prediction from the Hartree–Fock (HF) based random-phase approximation (RPA) [1]. These measurements confirm inelastic α-particle scattering as a suitable probe for exciting the ISGMR and the ISGDR modes in radioactive isotopes in inverse kinematics.

Published
2015
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20. Neutron occupancy of the 0d5/2 orbital and the N=16 shell closure in 24O

Author

K. Tshoo, Y. Satou, C.A. Bertulani, H. Bhang, S. Choi, T. Nakamura, Y. Kondo, S. Deguchi, Y. Kawada, Y. Nakayama, K.N. Tanaka, N. Tanaka, Y. Togano, N. Kobayashi, N. Aoi, M. Ishihara, T. Motobayashi, H. Otsu, H. Sakurai, S. Takeuchi, K. Yoneda, F. Delaunay, J. Gibelin, F.M. Marqués, N.A. Orr, T. Honda, T. Kobayashi, T. Sumikama, Y. Miyashita, K. Yoshinaga, M. Matsushita, S. Shimoura, D. Sohler, J.W. Hwang, T. Zheng, Z.H. Li, and Z.X. Cao

Subjects
Physics, QC1-999
Abstract

One-neutron knockout from 24O leading to the first excited state in 23O has been measured for a proton target at a beam energy of 62 MeV/nucleon. The decay energy spectrum of the neutron unbound state of 23O was reconstructed from the measured four momenta of the 22O fragment and emitted neutron. A sharp peak was found at Edecay=50±3 keV, corresponding to an excited state in 23O at 2.78±0.11 MeV, as observed in previous measurements. The longitudinal momentum distribution for this state was consistent with d-wave neutron knockout, providing support for a Jπ assignment of 5/2+. The associated spectroscopic factor was deduced to be C2S(0d5/2)=4.1±0.4 by comparing the measured cross section (σ−1nexp=61±6 mb) with a distorted wave impulse approximation calculation. Such a large occupancy for the neutron 0d5/2 orbital is in line with the N=16 shell closure in 24O.

Published
2014
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21. Corrigendum to 'Single-neutron knockout from 20C and the structure of 19C' [Phys. Lett. B 769 (2017) 503–508]

Author

J.W. Hwang, S. Kim, Y. Satou, N.A. Orr, Y. Kondo, T. Nakamura, J. Gibelin, N.L. Achouri, T. Aumann, H. Baba, F. Delaunay, P. Doornenbal, N. Fukuda, N. Inabe, T. Isobe, D. Kameda, D. Kanno, N. Kobayashi, T. Kobayashi, T. Kubo, S. Leblond, J. Lee, F.M. Marqués, R. Minakata, T. Motobayashi, D. Murai, T. Murakami, K. Muto, T. Nakashima, N. Nakatsuka, A. Navin, S. Nishi, S. Ogoshi, H. Otsu, H. Sato, Y. Shimizu, H. Suzuki, K. Takahashi, H. Takeda, S. Takeuchi, R. Tanaka, Y. Togano, A.G. Tuff, M. Vandebrouck, and K. Yoneda

Subjects
Physics, QC1-999
Published
2017
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22. Multiple Mechanisms in Proton-Induced Nucleon Removal at ∼100 MeV/Nucleon

Author

T. Pohl, Y. L. Sun, A. Obertelli, J. Lee, M. Gómez-Ramos, K. Ogata, K. Yoshida, B. S. Cai, C. X. Yuan, B. A. Brown, H. Baba, D. Beaumel, A. Corsi, J. Gao, J. Gibelin, A. Gillibert, K. I. Hahn, T. Isobe, D. Kim, Y. Kondo, T. Kobayashi, Y. Kubota, P. Li, P. Liang, H. N. Liu, J. Liu, T. Lokotko, F. M. Marqués, Y. Matsuda, T. Motobayashi, T. Nakamura, N. A. Orr, H. Otsu, V. Panin, S. Y. Park, S. Sakaguchi, M. Sasano, H. Sato, H. Sakurai, Y. Shimizu, A. I. Stefanescu, L. Stuhl, D. Suzuki, Y. Togano, D. Tudor, T. Uesaka, H. Wang, X. Xu, Z. H. Yang, K. Yoneda, and J. Zenihiro

Subjects
General Physics and Astronomy
Published
2023

23. Extended p3/2 Neutron Orbital and the N=32 Shell Closure in Ca52

Author

M. Enciu, H. N. Liu, A. Obertelli, P. Doornenbal, F. Nowacki, K. Ogata, A. Poves, K. Yoshida, N. L. Achouri, H. Baba, F. Browne, D. Calvet, F. Château, S. Chen, N. Chiga, A. Corsi, M. L. Cortés, A. Delbart, J-M. Gheller, A. Giganon, A. Gillibert, C. Hilaire, T. Isobe, T. Kobayashi, Y. Kubota, V. Lapoux, T. Motobayashi, I. Murray, H. Otsu, V. Panin, N. Paul, W. Rodriguez, H. Sakurai, M. Sasano, D. Steppenbeck, L. Stuhl, Y. L. Sun, Y. Togano, T. Uesaka, K. Wimmer, K. Yoneda, O. Aktas, T. Aumann, L. X. Chung, F. Flavigny, S. Franchoo, I. Gasparic, R.-B. Gerst, J. Gibelin, K. I. Hahn, D. Kim, Y. Kondo, P. Koseoglou, J. Lee, C. Lehr, P. J. Li, B. D. Linh, T. Lokotko, M. MacCormick, K. Moschner, T. Nakamura, S. Y. Park, D. Rossi, E. Sahin, P.-A. Söderström, D. Sohler, S. Takeuchi, H. Toernqvist, V. Vaquero, V. Wagner, S. Wang, V. Werner, X. Xu, H. Yamada, D. Yan, Z. Yang, M. Yasuda, and L. Zanetti

Subjects
General Physics and Astronomy
Published
2022

24. 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

25. 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

26. Study of spin-isospin responses of radioactive nuclei with the background-reduced neutron spectrometer, PANDORA

Author

N. Fukuda, Takashi Nakamura, H. Sakai, Yohei Shimizu, J. Gibelin, Makoto Yasuda, Tomotsugu Wakasa, M. Nishimura, J. Gao, Masashige Matsumoto, S. Franchoo, H. Miki, H. Kasahara, T. Harada, Masaki Sasano, D. Tudor, Toshio Kobayashi, T. Isobe, G. G. Kiss, Tomohiro Uesaka, Yasuhiro Togano, Susumu Shimoura, Atsumi Saito, N. Zhang, I. C. Stefanescu, E. Takada, Zoltán Halász, L. Trache, Yuya Kubota, D. Kim, T. Shimada, Shoko Koyama, Y. Fujino, Juzo Zenihiro, Z. Korkulu, D. Inomoto, Zaihong Yang, H. Sato, H. N. Liu, A. Spiridon, M. Miwa, H. Suzuki, L. Stuhl, V. Panin, H. Baba, Yosuke Kondo, S. Park, K. Yoneda, T. Motobayashi, Y. L. Sun, T. Tomai, I. S. Hahn, Kentaro Yako, X. Sun, A. Kurihara, M.N. Harakeh, Y. Hirai, D. S. Ahn, A. I. Chilug, Hideaki Otsu, Hiroki Yamada, Shin'ichiro Michimasa, K. Yoshida, 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), 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), 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, Research unit Nuclear & Hadron Physics, 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 Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear and High Energy Physics, Nuclear Theory, n) reactions, Inverse-kinematics (p, n) reactions, 01 natural sciences, Low-energy neutron detector, Inverse-kinematics [formula omitted] reactions, Nuclear physics, 0103 physical sciences, Figure-of-Merit (FoM), Neutron detection, Neutron, 010306 general physics, Spin (physics), Nuclear Experiment, Instrumentation, Gamow-Teller transition, DETECTOR, Real-time pulse-shape discrimination, Physics, [PHYS]Physics [physics], Spin-isospin response, Spectrometer, 010308 nuclear & particles physics, Figure-of-Merit (RIM), Detector, PULSE-SHAPE DISCRIMINATION, PLASTIC SCINTILLATOR, Inverse-kinematics (p, Isospin, Ground state, Beam (structure)
Abstract

The status of a project to measure spin-isospin responses of neutron drip-line nuclei using a new low-energy neutron detector, PANDORA (Particle Analyzer Neutron Detector Of Real-time Acquisition), is reported. The performance of PANDORA was characterized by the 6He(p,n)6Li reaction in inverse kinematics at the HIMAC facility in Chiba. Observation of the strong transition to the ground state in 6Li is discussed. Preliminary results of 11Li(p,n)11Be and 14Be(p,n)14B experiments in inverse kinematics at RI Beam Factory (RIBF) of RIKEN Nishina Center are also presented including the exotic decay channel of 11Be→9Li + d. Details of the experimental setup based on PANDORA and the SAMURAI large-acceptance magnetic spectrometer, as well as the combined data-acquisition system are described. The neutron-gamma discrimination capability of PANDORA was evaluated, Figure-of-Merit (FoM) values higher than those found in the literature for similar materials were derived from experimental data.

Published
2020

27. Observation of a correlated free four-neutron system

Author

M. Duer, T. Aumann, R. Gernhäuser, V. Panin, S. Paschalis, D. M. Rossi, N. L. Achouri, D. Ahn, H. Baba, C. A. Bertulani, M. Böhmer, K. Boretzky, C. Caesar, N. Chiga, A. Corsi, D. Cortina-Gil, C. A. Douma, F. Dufter, Z. Elekes, J. Feng, B. Fernández-Domínguez, U. Forsberg, N. Fukuda, I. Gasparic, Z. Ge, J. M. Gheller, J. Gibelin, A. Gillibert, K. I. Hahn, Z. Halász, M. N. Harakeh, A. Hirayama, M. Holl, N. Inabe, T. Isobe, J. Kahlbow, N. Kalantar-Nayestanaki, D. Kim, S. Kim, T. Kobayashi, Y. Kondo, D. Körper, P. Koseoglou, Y. Kubota, I. Kuti, P. J. Li, C. Lehr, S. Lindberg, Y. Liu, F. M. Marqués, S. Masuoka, M. Matsumoto, J. Mayer, K. Miki, B. Monteagudo, T. Nakamura, T. Nilsson, A. Obertelli, N. A. Orr, H. Otsu, S. Y. Park, M. Parlog, P. M. Potlog, S. Reichert, A. Revel, A. T. Saito, M. Sasano, H. Scheit, F. Schindler, S. Shimoura, H. Simon, L. Stuhl, H. Suzuki, D. Symochko, H. Takeda, J. Tanaka, Y. Togano, T. Tomai, H. T. Törnqvist, J. Tscheuschner, T. Uesaka, V. Wagner, H. Yamada, B. Yang, L. Yang, Z. H. Yang, M. Yasuda, K. Yoneda, L. Zanetti, J. Zenihiro, M. V. Zhukov, 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, 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), Research unit Nuclear & Hadron Physics, and Nuclear Energy

Subjects
Multidisciplinary, Nuclear Force, Nuclear Structure, Tetraneutron, Reactions with Radioactive Beams, Physics, ddc:500, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

Nature 606(7915), 678 - 682 (2022). doi:10.1038/s41586-022-04827-6, Published by Nature Publ. Group, London [u.a.]

Published
2022

28. 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

29. Silicon tracker array for RIB experiments at SAMURAI

Author

A. I. Stefanescu, V. Panin, L. Trache, T. Motobayashi, H. Otsu, A. Saastamoinen, T. Uesaka, L. Stuhl, J. Tanaka, D. Tudor, I. C. Stefanescu, A. E. Spiridon, K. Yoneda, H. Baba, M. Kurokawa, Y. Togano, Z. Halasz, M. Sasano, S. Ota, Y. Kubota, D. S. Ahn, T. Kobayashi, Z. Elekes, N. Fukuda, H. Takeda, D. Kim, E. Takada, H. Suzuki, K. Yoshida, Y. Shimizu, H. N. Liu, Y. L. Sun, T. Isobe, J. Gibelin, P. J. Li, J. Zenihiro, F. M. Marqués, M. N. Harakeh, G. G. Kiss, A. Kurihara, M. Yasuda, T. Nakamura, S. Park, Z. Yang, T. Harada, M. Nishimura, H. Sato, I. S. Hahn, K. Y. Chae, J. M. Elson, L. G. Sobotka, C. A. Bertulani, 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, 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), 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
Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Nuclear Experiment (nucl-ex), Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Nuclear Experiment
Abstract

International audience; This work describes a silicon tracker system developed for experiments with proton-rich radioactive ion beams at the SAMURAI superconducting spectrometer of RIBF at RIKEN. The system is designed for accurate angular reconstruction and atomic number identification of relativistic heavy ions and protons which are simultaneously produced in reactions motivated by studies of proton capture reactions of interest for nuclear astrophysics. The technical characteristics of the tracking array are described in detail as are its performance in two pilot experiments. The physics justification for such a system is also presented.

Published
2022

30. 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

31. Quasifree Neutron Knockout Reaction Reveals a Small s -Orbital Component in the Borromean Nucleus B17

Author

Shuichi Ota, V. Panin, A. Ohkura, Toshiyuki Sumikama, Y. Kiyokawa, Takashi Nakamura, J. Yasuda, T. Isobe, S. Kawakami, Y. Kanaya, Ji Feng, H. Sato, A. Giganon, K. Hasegawa, D. Kim, C. Caesar, Toshio Kobayashi, K. Yoneda, Masanori Dozono, Noritsugu Nakatsuka, Motoki Kobayashi, Juzo Zenihiro, Atsumi Saito, Tsuyoshi Miyazaki, Shoko Koyama, J.-Y. Roussé, Y.L. Sun, Z. Korkulu, Nagao Kobayashi, C. Santamaria, Y. Shindo, Stefanos Paschalis, F. Flavigny, Nicolas Michel, E. C. Pollacco, Yasuhiro Togano, A. Corsi, Yukie Maeda, C. X. Yuan, N. A. Orr, L. Stuhl, Hideaki Otsu, Shan-Gui Zhou, D. Calvet, Tomohiro Uesaka, F. M. Marqués, A. Delbart, G. Authelet, J. M. Gheller, M. Sako, Yohei Shimizu, Yuya Kubota, A. Gillibert, Y. Nishio, T. Ozaki, S. Reichert, J. Tsubota, Kazuyuki Ogata, Wei Zuo, Zaihong Yang, M. Shikata, K. Yoshida, Qiang Yuan, J. Gibelin, V. Lapoux, Masaki Sasano, H. Baba, Furong Xu, A. Obertelli, Masaaki Kimura, Xianping Sun, Yosuke Kondo, M. Tabata, T. Motobayashi, Satoshi Sakaguchi, and J. G. Li

Subjects
Physics, Component (thermodynamics), Nuclear Theory, General Physics and Astronomy, 01 natural sciences, Momentum, Nuclear physics, Atomic orbital, Borromean nucleus, 0103 physical sciences, Neutron, Continuum (set theory), Halo, 010306 general physics, Astrophysics::Galaxy Astrophysics
Abstract

A kinematically complete quasifree (p,pn) experiment in inverse kinematics was performed to study the structure of the Borromean nucleus ^{17}B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for 1s_{1/2} and 0d_{5/2} orbitals, and a surprisingly small percentage of 9(2)% was determined for 1s_{1/2}. Our finding of such a small 1s_{1/2} component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in ^{17}B. The present work gives the smallest s- or p-orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of s or p orbitals is not a prerequisite for the occurrence of a neutron halo.

Published
2021

32. Quasi-free Neutron Knockout Reaction Reveals a Small $s$-orbital Component in the Borromean Nucleus $^{17}$B

Author

Z H, Yang, Y, Kubota, A, Corsi, K, Yoshida, X-X, Sun, J G, Li, M, Kimura, N, Michel, K, Ogata, C X, Yuan, Q, Yuan, G, Authelet, H, Baba, C, Caesar, D, Calvet, A, Delbart, M, Dozono, J, Feng, F, Flavigny, J-M, Gheller, J, Gibelin, A, Giganon, A, Gillibert, K, Hasegawa, T, Isobe, Y, Kanaya, S, Kawakami, D, Kim, Y, Kiyokawa, M, Kobayashi, N, Kobayashi, T, Kobayashi, Y, Kondo, Z, Korkulu, S, Koyama, V, Lapoux, Y, Maeda, F M, Marqués, T, Motobayashi, T, Miyazaki, T, Nakamura, N, Nakatsuka, Y, Nishio, A, Obertelli, A, Ohkura, N A, Orr, S, Ota, H, Otsu, T, Ozaki, V, Panin, S, Paschalis, E C, Pollacco, S, Reichert, J-Y, Roussé, A T, Saito, S, Sakaguchi, M, Sako, C, Santamaria, M, Sasano, H, Sato, M, Shikata, Y, Shimizu, Y, Shindo, L, Stuhl, T, Sumikama, Y L, Sun, M, Tabata, Y, Togano, J, Tsubota, F R, Xu, J, Yasuda, K, Yoneda, J, Zenihiro, S-G, Zhou, W, Zuo, T, Uesaka, 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, 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), 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), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear Theory, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment, Astrophysics::Galaxy Astrophysics, Nuclear Physics
Abstract

A kinematically complete quasi-free $(p,pn)$ experiment in inverse kinematics was performed to study the structure of the Borromean nucleus $^{17}$B, which had long been considered to have neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for $1s_{1/2}$ and $0d_{5/2}$ orbitals, and a surprisingly small percentage of 9(2)$\%$ was determined for $1s_{1/2}$. Our finding of such a small $1s_{1/2}$ component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in $^{17}$B. The present work gives the smallest $s$- or $p$-orbital component among known nuclei exhibiting halo features, and implies that the dominant occupation of $s$ or $p$ orbitals is not a prerequisite for the occurrence of neutron halo., Accepted for publication in Physical Review Letters,8 pages, 4 figures

Published
2021

33. Structure of superheavy hydrogen 7H

Author

Naoyuki Itagaki, A. M. Moro, J. Gibelin, D. Cortina-Gil, C. Rodríguez Tajes, B. Fernández–Domínguez, G. F. Grinyer, F. Farget, D. Perez Loureiro, Riccardo Raabe, J. Pancin, J. Benlliure, S. Sambi, S. Bagchi, M. Caamaño, Bertrand Jacquot, T. Roger, Marine Vandebrouck, H. Savajols, B. Pietras, D. Ramos, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire 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), Universidade de Santiago de Compostela [Spain] (USC ), 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), Universidad de Sevilla / University of Sevilla, KVI-CART, University of Groningen, University of Groningen [Groningen], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Yukawa Institute for Theoretical Physics (YITP), Kyoto University, and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, [PHYS]Physics [physics], Proton, Hydrogen, 010308 nuclear & particles physics, QC1-999, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, chemistry.chemical_element, Nuclear matter, 01 natural sciences, 7. Clean energy, Nuclear physics, chemistry, Pairing, 0103 physical sciences, Nuclear force, Neutron, Halo, 010306 general physics, Ground state, Nuclear Experiment
Abstract

The properties of nuclei with extreme neutron–to–proton ratios reveal the limitations of state-ofthe-art nuclear models and are key to understand nuclear forces. 7H, with six neutrons and a single proton, is the nuclear system with the most unbalanced neutron–to–proton ratio ever known, but its sheer existence and properties are still a challenge for experimental efforts and theoretical models. We report here the first measurement of the basic characteristics and structure of the ground state of 7H; they depict a system with a triton core surrounded by an extended four-neutron halo, built by neutron pairing, that decays through a unique four–neutron emission with a relatively long half-life. These properties are a prime example of new phenomena occurring in almost pure-neutron nuclear matter, beyond the binding limits of the nuclear landscape, that are yet to be described within our current models.

Published
2020

34. Spectroscopy of $^{16}$B from quasi-free ($p,pn$) reaction with $^{17}$B

Author

T. Kobayashi, Yosuke Kondo, J. Yasuda, Alessandra Corsi, D. Calvet, T. Isobe, Y. Kanaya, H. Sato, K. Hasegawa, Atsumi Saito, C. Santamaria, Tsuyoshi Miyazaki, Toshiyuki Sumikama, Satoshi Sakaguchi, Y. Shindo, T. Ozaki, M. Shikata, G. Authelet, J. M. Gheller, J. Tsubota, M. Tabata, S. Kawakami, Noritsugu Nakatsuka, D. Kim, T. Motobayashi, Motoki Kobayashi, Shoko Koyama, K. Yoneda, Z. Korkulu, H. Baba, Y. Nishio, T. Uesaka, A. Ohkura, Juzo Zenihiro, V. Lapoux, Masaki Sasano, J.-Y. Roussé, Y. Kiyokawa, A. Giganon, Yasuhiro Togano, A. Gillibert, Yuya Kubota, A. Obertelli, S. Reichert, Takashi Nakamura, Ji Feng, N. A. Orr, Y. L. Sun, S. Ota, J. Gibelin, C. Caesar, M. Sako, V. Panin, Yohei Shimizu, Zaihong Yang, L. Stuhl, F. M. Marqués, Yukie Maeda, Nagao Kobayashi, Stefanos Paschalis, F. Flavigny, A. Delbart, Masanori Dozono, E. C. Pollacco, Hideaki Otsu, 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 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), 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), École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Paper, History, 010308 nuclear & particles physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Molecular physics, 3. Good health, Computer Science Applications, Education, ddc, TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, 0103 physical sciences, Halo, 010306 general physics, Spectroscopy
Abstract

Spectroscopy of 16B plays an essential role in understanding the halo structure in 17B, but very limited knowledge has so far been obtained. We have carried out a kinematically complete measurement on the spectroscopy of 16B by using quasi-free (p,pn) reaction on 17B. The level scheme of 16B up to 5 MeV was made clear for the first time.

Published
2020

35. Experimental study of 4 n with 8He(p,2p) reaction

Author

M. Böhmer, Masaki Sasano, S. Reichert, Naohito Inabe, S. Chen, T. Shimada, M. Matsumoto, Susumu Shimoura, I. Stefan, J. Kahlbow, N. Kalantar-Nayestanaki, T. Harada, D. Symochko, István Kuti, S. W. Huang, D. Cortina, Tomohiro Uesaka, Z. Ge, N. L. Achouri, Yosuke Kondo, Hiroyuki Takeda, K. Yoneda, B. Fernández-Domínguez, U. Forsberg, Z. Elekes, Roman Gernhäuser, Y. Yasuda, H. Suzuki, Yohei Shimizu, D. Beaumel, D. Kim, C. A. Douma, Yukie Maeda, A. Hirayama, J. M. Gheller, Heiko Scheit, F. Dufter, T. Elidiano, Yasuhiro Togano, M. L. Cortés, M. Potlog, Nobuyuki Chiga, P. J. Li, Juzo Zenihiro, B. Yang, T. Isobe, M. Caamaño, Thomas Aumann, H. T. Törnqvsit, A. Gillibert, D. S. Ahn, F. Schindler, M.N. Harakeh, J. Feng, J. Tscheuschner, S. Kim, Atsumi Saito, L. Zanetti, P. Koseoglou, V. Wagner, M. Parlog, B. M. Godoy, N. Orr, Takashi Nakamura, Yu-xin Liu, J. Mayer, A. Obertelli, Yuya Kubota, Hideaki Otsu, S. Storck, S. Masuoka, K. Boretzky, Kathrin Wimmer, H. Miki, T. Tomai, F. M. Marqués, V. Panin, P. Doornenbal, Stefanos Paschalis, L. Yang, Satoshi Takeuchi, M. A. Knösel, Igor Gašparić, T. Kobayashi, C. Lehr, H. Yang, C. Lenain, M. Miwa, Z. Halász, A. Revel, H. Sato, T. Fujino, D. M. Rossi, H. Baba, S. Park, I. Murray, L. Stuhl, H. Yamada, J. Gibelin, J. Tanaka, Naoki Fukuda, RIKEN Nishina Center for Accelerator-Based Science, German Research Foundation, Federal Ministry of Education and Research (Germany), 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 Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and 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, Paper, History, 010308 nuclear & particles physics, tetraneutron, nuclear force, proton knock-out, radioactive beams, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Computer Science Applications, Education, ddc, Nuclear physics, 0103 physical sciences, Tetraneutron, Neutron, ddc:530, 010306 general physics
Abstract

7 pags., 3 figs. -- 27th International Nuclear Physics Conference (INPC2019), The tetraneutron has attracted the attention of nuclear physicists during the past decades, but there is still no unambiguous confirmation of its existence or nonexistence. A new experiment based on 8 He(p,2p)7H{t+4n} reaction, with direct detection of the four neutrons, has been carried out at RIBF, which can hopefully help to draw a definite conclusion on the tetraneutron system., We acknowledge the support of the RIBF accelerator staff and the BigRIPS team for providing the high-quality beam. Z. H. Yang acknowledges the financial support from the Foreign Postdoctoral Researcher program of RIKEN. T. Aumann acknowledges the support by DFG via SFB 1245. P. Koseoglou acknowledges the support from BMBF (NUSTAR.DA grant No.05P 15RDFN1).

Published
2020

36. Structure of 13Be probed via quasi-free scattering

Author

M. Gómez-Ramos, Yuya Kubota, Takashi Nakamura, Tsuyoshi Miyazaki, Yukie Maeda, J. Casal, H. Sato, J. Tsubota, A. Gillibert, Michikazu Kobayashi, J. Gibelin, C. Caesar, V. Lapoux, Y. Shindo, M. Sako, K. Hasegawa, Y. Nishio, A. Ohkura, K. Yoneda, S. Kawakami, V. Panin, A. M. Moro, A. Obertelli, T. Uesaka, G. Authelet, Yosuke Kondo, Masanori Dozono, J.-Y. Roussé, J. M. Gheller, T. Ozaki, C. Santamaria, Yohei Shimizu, S. Reichert, Y. Kiyokawa, Zaihong Yang, Hidetada Baba, Y. Kanaya, T. Isobe, D. Kim, Yasuhiro Togano, E. C. Pollacco, A. Giganon, M. Shikata, F. M. Marqués, M. Tabata, Hideaki Otsu, T. Motobayashi, Nagao Kobayashi, Stefanos Paschalis, F. Flavigny, Shoko Koyama, A. Delbart, L. Stuhl, Z. Korkulu, Satoshi Sakaguchi, Masaki Sasano, A. Corsi, S. Ota, Y.L. Sun, D. Calvet, Atsumi Saito, Toshiyuki Sumikama, Toshio Kobayashi, Noritsugu Nakatsuka, Juzo Zenihiro, J. Feng, N.A. Orr, J. Yasuda, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Département des Accélérateurs, de Cryogénie et de Magnétisme (ex SACM) (DACM), 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, 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), 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), 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 Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear and High Energy Physics, Nuclear Theory, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Interpretation (model theory), Nuclear Theory (nucl-th), 0103 physical sciences, Three-body model, medicine, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Wave function, Nuclear Experiment, Quasi-free scattering, Physics, Borromean nuclei, Resonances, Inverse kinematics, 010308 nuclear & particles physics, Scattering, Spectrum (functional analysis), lcsh:QC1-999, medicine.anatomical_structure, Atomic physics, Nucleon, Nucleus, lcsh:Physics
Abstract

We present an investigation of the structure of 13Be obtained via a kinematically complete measurement of the (p,pn) reaction in inverse kinematics at 265 MeV/nucleon. The relative energy spectrum of 13Be is compared to Transfer-to-the-Continuum calculations which use as structure inputs the overlaps of the 14Be ground-state wave function, computed in a three-body model, with the unbound states of the 13Be residual nucleus. The key role of neutron p-wave orbital in the interpretation of the low-relative-energy part of the spectrum is discussed. Keywords: Quasi-free scattering, Borromean nuclei, Three-body model, Resonances

Published
2019

37. Nuclear Breakup and Coulomb Dissociation of $^{9}$C Nucleus Studied at RIBF RIKEN

Author

Livius Trache, H. Baba, M.N. Harakeh, H. N. Liu, H. Takeda, F. M. Marques, Zoltán Halász, T. Isobe, H. Murakami, H. Otsu, J. Zenihiro, D. H. Kim, M. Sasano, S. Y. Park, Z. Yang, I. C. Stefanescu, D. Tudor, T. Motobayashi, Masahiro Yasuda, A. E. Spiridon, A. N. Petrovici, Y. L. Sun, Takashi Nakamura, Naoki Fukuda, Y. Kubota, K. Yoneda, Masanori Nishimura, Y. Shimizu, T. Uesaka, Yasuhiro Togano, P. J. Li, A. Kurihara, K. Y. Chae, H. Suzuki, D. S. Ahn, A. I. Chilug, T. Kobayashi, J. Gibelin, Shuichi Ota, I. S. Hahn, L. Stuhl, F. Carstoiu, N. T. Zhang, Z. Elekes, Antti Saastamoinen, H. Sato, G. G. Kiss, T. Harada, V. Panin, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), 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
Physics, Hydrogen, Explosive material, 010308 nuclear & particles physics, chemistry.chemical_element, Inverse, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Breakup, 01 natural sciences, 7. Clean energy, Dissociation (chemistry), Nuclear physics, chemistry, 0103 physical sciences, Radiative transfer, Coulomb, 010306 general physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Mass gap
Abstract

International audience; The 9C breakup was studied during the SAMURAI29R1 experiment through inclusive and exclusive measurements at energies around 160 AMeV for 9C, in order to evaluate the astrophysical S18 factor for the inverse process 8B(p,γ)9C at energies in the region of astrophysical interest. The radiative proton capture on 8B is important in the hot pp chains, in explosive Hydrogen burning (ppIV and rapI), at temperatures between 0.05 < T9 < 1 K, as possible alternative paths across the A = 8 mass gap. Another goal of this experiment was a detailed study of the breakup reaction mechanism. During the experiment the nuclear breakup process was studied using a natural C target with 425 µm thickness and the Coulomb dissociation by using a natural Pb target with 150 µm thickness. The reaction products were tracked simultaneously using a system of position sensitive Si detectors and in total 1024 output channels were read out by using new dual gain preamplifiers (DGP) specially designed for the experiments of the HI-p collaboration. The SAMURAI29R1 experiment was carried out during the SAMURAI 18Oxygen 2018 Spring campaign and it is part of the HI-p collaboration together with another three experiments. Performances of the setup used and first results of the analysis are presented.

Published
2018

38. Study of spin-isospin response of 11Li neutron-drip-line nucleus with PANDORA

Author

Masaki Sasano, M. Miwa, T. Kobayashi, I. C. Stefanescu, D. Tudor, Tomohiro Uesaka, T. Isobe, K. Yoneda, D. Inomoto, Zaihong Yang, M. Nishimura, L. Stuhl, H. Baba, I. S. Hahn, D. Kim, K. Yoshida, A. I. Chilug, Y. Fujino, H. Suzuki, H. Sato, Yosuke Kondo, Zoltán Halász, H. Kasahara, Kentaro Yako, Tomotsugu Wakasa, Yasuhiro Togano, G. G. Kiss, T. Motobayashi, T. Shimada, Shin'ichiro Michimasa, X. Sun, Naoki Fukuda, Juzo Zenihiro, H. N. Liu, Takashi Nakamura, S. Park, Masashige Matsumoto, H. Miki, Y. Hirai, V. Panin, Hiroki Yamada, A. Spiridon, T. Tomai, Susumu Shimoura, Y. L. Sun, D. S. Ahn, M. N. Harakeh, H. Sakai, Makoto Yasuda, A. Kurihara, Atsumi Saito, N. Zhang, L. Trache, Yuya Kubota, J. Gibelin, Yohei Shimizu, S. Franchoo, Hideaki Otsu, J. Gao, Shoko Koyama, Z. Korkulu, T. Harada, 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), 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, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, History, 010308 nuclear & particles physics, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Computer Science Applications, Education, Nuclear physics, medicine.anatomical_structure, Isospin, 0103 physical sciences, medicine, Nuclear drip line, Nuclear Experiment, 010306 general physics, Nucleus, Spin-½
Abstract

The spin-isospin responses of the 11Li drip-line nucleus has been measured. Preliminary results of the 11Li(p, n)11Be experiment in inverse kinematics at RI Beam Factory (RIBF) of RIKEN Nishina Center are presented including the observation of 1n, 2n, t, d, 2α and 6He+α decay channels of 11Be reaction product. Details of the experimental setup based on PANDORA (Particle Analyzer Neutron Detector Of Real-time Acquisition) low-energy neutron detector and the SAMURAI large-acceptance magnetic spectrometer are described.

Published
2020

39. Observation of isoscalar multipole strengths in exotic doubly-magic 56Ni in inelastic α scattering in inverse kinematics

Author

N.L. Achouri, Marine Vandebrouck, S. Damoy, Elias Khan, H. Bouzomita, M. Fujiwara, K. Mazurek, L. Caceres, J. F. Libin, J. Van de Walle, M. Caamaño, U. Garg, S. M. Lukyanov, H. Savajols, A. Krasznahorkay, J. Pancin, K. Boretzky, B. Bastin, S. Bagchi, G. F. Grinyer, G. Lhoutellier, C. Stodel, Riccardo Raabe, L. Suen, J. Gibelin, Nasser Kalantar-Nayestanaki, Catherine Rigollet, Hidetoshi Akimune, S. Sambi, J. C. Thomas, O. Kamalou, L. Perrot, M. A. Najafi, T. Roger, M. Senoville, F. Delaunay, B. Fernández-Domínguez, Y. E. Penionzhkevich, M.N. Harakeh, Universidade de Santiago de Compostela. Departamento de Física de Partículas, KVI-CART, University of Groningen, University of Groningen [Groningen], 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), Universidade de Santiago de Compostela [Spain] (USC ), 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), Institute for Nuclear Research [Budapest] (ATOMKI), Hungarian Academy of Sciences (MTA), Flerov Laboratory of Nuclear Reactions [Dubna] (FLNR), Joint Institute for Nuclear Research (JINR), Instituut voor Kern-en Stralingsfysica (IKS), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), GANILEXP, Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-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)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Research unit Nuclear & Hadron Physics

Subjects
Nuclear and High Energy Physics, Isoscalar, ACTIVE TARGET, Nuclear Theory, Magnetic monopole, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Resonance (particle physics), NUCLEAR INCOMPRESSIBILITY, Nuclear physics, ENERGY, ddc:530, Nuclear Experiment, Physics, Inverse kinematics, Isotope, Scattering, BEAMS, lcsh:QC1-999, 3. Good health, Dipole, ISOTOPES, DIPOLE RESONANCE, Atomic physics, Multipole expansion, MATTER, lcsh:Physics
Abstract

The Isoscalar Giant Monopole Resonance (ISGMR) and the Isoscalar Giant Dipole Resonance (ISGDR) compression modes have been studied in the doubly-magic unstable nucleus 56Ni. They were measured by inelastic α-particle scattering in inverse kinematics at 50MeV/u with the MAYA active target at the GANIL facility. The centroid of the ISGMR has been obtained at Ex=19.1 ±0.5MeV. Evidence for the low-lying part of the ISGDR has been found at Ex=17.4 ±0.7MeV. The strength distribution for the dipole mode shows similarity with the prediction from the Hartree–Fock (HF) based random-phase approximation (RPA)[1]. These measurements confirm inelastic α-particle scattering as a suitable probe for exciting the ISGMR and the ISGDR modes in radioactive isotopes in inverse kinematics This work was supported by the European Commission within the Seventh Framework Programme through IA-ENSAR (contract No. RII3-CT-2010-262010) and GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, and the United States National Science Foundation (Grants Number PHY-1068192 and PHY-1419765) SI

Published
2015

40. Structure of Beryllium Isotopes Beyond the Neutron Dripline

Author

V. Panin, Tsuyoshi Miyazaki, K. Yoneda, T. Isobe, S. Reichert, T. Uesaka, K. Hasegawa, Y. Shindo, Nagao Kobayashi, Stefanos Paschalis, F. Flavigny, J. Gibelin, C. Caesar, T. Ozaki, D. Kim, J.-Y. Roussé, Yuya Kubota, Yasuhiro Togano, F. M. Marqués, Yohei Shimizu, Takashi Nakamura, Zaihong Yang, Ji Feng, M. Sako, G. Authelet, J. M. Gheller, T. Kobayashi, E. C. Pollacco, Hideaki Otsu, Masanori Dozono, Yukie Maeda, Atsumi Saito, V. Lapoux, L. Stuhl, D. Calvet, M. Shikata, Toshiyuki Sumikama, Satoshi Sakaguchi, Noritsugu Nakatsuka, Juzo Zenihiro, A. Corsi, A. Delbart, Masaki Sasano, A. Ohkura, J. Yasuda, Motoki Kobayashi, Shoko Koyama, Z. Korkulu, Y. Kanaya, H. Sato, Yosuke Kondo, A. Gillibert, Y. Kiyokawa, A. Obertelli, Y. Nishio, A. Giganon, M. Tabata, T. Motobayashi, S. Kawakami, H. Baba, B. Monteagudo, J. Tsubota, C. Santamaria, N. A. Orr, S. Ota, 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, 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), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Nuclear structure, Structure (category theory), 01 natural sciences, 7. Clean energy, Nuclear physics, medicine.anatomical_structure, 0103 physical sciences, medicine, Spontaneous emission, Neutron, 010306 general physics, Isotopes of beryllium, Nuclear Experiment, Nucleus, Beam (structure)
Abstract

International audience; Dineutron decay is a forefront topic in nuclear structure that still lacks a firm experimental claim. The spontaneous emission of a dineutron should be favored in nuclei that are unbound with respect to two-neutron emission but bound with respect to single-neutron emission. A very interesting candidate can be found by adding two neutrons to the most neutron-rich Beryllium isotope,$^{14}$Be, a well-known 2n-halo nucleus. The intriguing nature of the phenomenon has motivated recent theoretical calculations and a new experimental campaign at RIKEN RIBF. In this work, the decay properties of$^{16}$Be and the structure of$^{15}$Be have been probed via the proton-knockout reaction from a$^{17}$B beam.

Published
2018

41. Neutron occupancy of the 0d5/2 orbital and the N=16 shell closure in 24O

Author

Y. Kawada, Y. Nakayama, Dóra Sohler, H. Bhang, N. A. Orr, Carlos A. Bertulani, T. Zheng, K. Tshoo, F. Delaunay, Masafumi Matsushita, Satoshi Takeuchi, Jongwon Hwang, Kenichiro Yoneda, N. Tanaka, T. Honda, T. Kobayashi, S. Deguchi, N. Kobayashi, Z X Cao, Takashi Nakamura, Susumu Shimoura, Hideaki Otsu, Nori Aoi, S. Choi, J. Gibelin, Tohru Motobayashi, Kanenobu Tanaka, Yasuhiro Togano, Hiroyoshi Sakurai, F M Marques, K. Yoshinaga, Z. H. Li, Yosuke Kondo, M. Ishihara, Y. Miyashita, Y. Satou, and Toshiyuki Sumikama

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Nuclear Theory, Impulse (physics), 01 natural sciences, Decay energy, Excited state, 0103 physical sciences, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Beam energy
Abstract

One-neutron knockout from 24O leading to the first excited state in 23O has been measured for a proton target at a beam energy of 62 MeV/nucleon. The decay energy spectrum of the neutron unbound state of 23O was reconstructed from the measured four momenta of the 22O fragment and emitted neutron. A sharp peak was found at E decay = 50 ± 3 keV , corresponding to an excited state in 23O at 2.78 ± 0.11 MeV , as observed in previous measurements. The longitudinal momentum distribution for this state was consistent with d-wave neutron knockout, providing support for a J π assignment of 5 / 2 + . The associated spectroscopic factor was deduced to be C 2 S ( 0 d 5 / 2 ) = 4.1 ± 0.4 by comparing the measured cross section ( σ − 1 n exp = 61 ± 6 mb ) with a distorted wave impulse approximation calculation. Such a large occupancy for the neutron 0 d 5 / 2 orbital is in line with the N = 16 shell closure in 24O.

Published
2014

42. Corrigendum to 'Single-neutron knockout from 20 C and the structure of 19 C' [Phys. Lett. B 769 (2017) 503–508]

Author

T. Nakashima, S. Ogoshi, Shuichi Takeuchi, T. Murakami, Takashi Nakamura, Nagao Kobayashi, N.A. Orr, Jongwon Hwang, S. K. Kim, Noritsugu Nakatsuka, K. Yoneda, T. Isobe, Y. Togano, S. Leblond, N.L. Achouri, A. Navin, Naoki Fukuda, Takashi Kubo, Thomas Aumann, Jenny Lee, D. Kanno, Hiroshi Sato, Naohito Inabe, Hiroshi Suzuki, H. Takeda, S. Nishi, Daichi Murai, Hideaki Otsu, D. Kameda, K. Muto, Yosuke Kondo, K. Takahashi, Y. Satou, F. M. Marqués, P. Doornenbal, T. Motobayashi, A. G. Tuff, Y. Shimizu, J. Gibelin, F. Delaunay, T. Kobayashi, Marine Vandebrouck, H. Baba, Ryuki Tanaka, and R. Minakata

Subjects
Physics, Nuclear and High Energy Physics, Structure (category theory), Neutron, Atomic physics, lcsh:Physics, lcsh:QC1-999
Published
2017

43. 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

44. Invariant Mass Spectroscopy of 23O via the (p, p′) Reaction in Inverse Kinematics

Author

Hiroyoshi Sakurai, F. Delaunay, Y. Nakayama, T. Zheng, Satoshi Takeuchi, T. Honda, N. A. Orr, Y. Satou, Dóra Sohler, N. Kobayashi, H. Bhang, Kanenobu Tanaka, Hideaki Otsu, Y. Miyashita, Masafumi Matsushita, Y. Kawada, S. Choi, F M Marques, Yosuke Kondo, K. Yoshinaga, Jongwon Hwang, M. Ishihara, J. Gibelin, T. Kobayashi, Tohru Motobayashi, K. Tshoo, Z X Cao, Yasuhiro Togano, S. Deguchi, T. Sumikama, Z. H. Li, Takashi Nakamura, Kenichiro Yoneda, Susumu Shimoura, N. Tanaka, Nori Aoi, 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), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Inverse kinematics, Proton, 010308 nuclear & particles physics, Nuclear Theory, Inelastic scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Resonance (particle physics), Atomic and Molecular Physics, and Optics, 0103 physical sciences, Invariant mass, Neutron, Atomic physics, 010306 general physics, Nucleon, Spectroscopy, Nuclear Experiment
Abstract

The neutron-rich oxygen isotope O-23 has been investigated via proton inelastic scattering on a liquid hydrogen target at 63.5 MeV/nucleon. The invariant mass method in inverse kinematics was employed to reconstruct the energy spectrum. A sharp resonance state was observed at 42(5) keV above the neutron threshold. A comparison of the differential cross section leading to this state with a microscopic DWBA calculation allowed a J (pi) assignment of 5/2(+) for this state.

Published
2013

45. Nucleus $^{26}$O: A Barely Unbound System beyond the Drip Line

Author

Y, Kondo, T, Nakamura, R, Tanaka, R, Minakata, S, Ogoshi, N A, Orr, N L, Achouri, T, Aumann, H, Baba, F, Delaunay, P, Doornenbal, N, Fukuda, J, Gibelin, J W, Hwang, N, Inabe, T, Isobe, D, Kameda, D, Kanno, S, Kim, N, Kobayashi, T, Kobayashi, T, Kubo, S, Leblond, J, Lee, F M, Marqués, T, Motobayashi, D, Murai, T, Murakami, K, Muto, T, Nakashima, N, Nakatsuka, A, Navin, S, Nishi, H, Otsu, H, Sato, Y, Satou, Y, Shimizu, H, Suzuki, K, Takahashi, H, Takeda, S, Takeuchi, Y, Togano, A G, Tuff, M, Vandebrouck, K, Yoneda, 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), 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), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

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

International audience; The unbound nucleus 26O has been investigated using invariant-mass spectroscopy following one-proton removal reaction from a 27F beam at 201 MeV/nucleon. The decay products, 24O and two neutrons, were detected in coincidence using the newly commissioned SAMURAI spectrometer at the RIKEN Radioactive Isotope Beam Factory. The 26O ground-state resonance was found to lie only 18±3(stat)±4(syst) keV above threshold. In addition, a higher lying level, which is most likely the first 2+ state, was observed for the first time at 1.28+0.11−0.08 MeV above threshold. Comparison with theoretical predictions suggests that three-nucleon forces, pf-shell intruder configurations, and the continuum are key elements to understanding the structure of the most neutron-rich oxygen isotopes beyond the drip line.

Published
2016

46. Invariant mass spectroscopy for the neutron rich nuclei

Author

Kanenobu Tanaka, F. Delaunay, Naoki Fukuda, Takashi Sugimoto, N. Tanaka, Y. Kawada, Hooi Jin Ong, Dóra Sohler, H. Bhang, Z. H. Li, T. Honda, N. A. Orr, S. Deguchi, Masafumi Matsushita, J. Gibelin, Tohru Motobayashi, Y. Nakayama, T. Zheng, K. Tshoo, Nori Aoi, Y. Satou, Z X Cao, Yoshiyuki Yanagisawa, F M Marques, N. Kobayashi, Satoshi Takeuchi, Hideaki Otsu, S. Choi, K. Yoshinaga, T. Kobayashi, Y. Miyashita, Kenichiro Yoneda, Susumu Shimoura, T. Sumikama, Yasuhiro Togano, Takashi Nakamura, Yosuke Kondo, Yasuhiro H. Matsuda, M. Ishihara, Hiroyoshi Sakurai, 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), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Radioactive isotope beams, Gamow-teller transition, Proton, Neutron emission, DWBA analysis, Nuclear Theory, General Physics and Astronomy, n) reactions, Isotopes of boron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Nuclear physics, (p, 0103 physical sciences, Neutron, Invariant mass, 010306 general physics, Spectroscopy, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Invariant mass method, Momentum transfer, p ') and (p, Atomic physics, Nucleon
Abstract

The neutron-rich carbon isotopes (19,17)C and a boron isotope (14)B are investigated respectively via proton inelastic and charge-exchange reactions on a liquid hydrogen target at around 70 MeV/nucleon at RIKEN. The invariant mass method in inverse kinematics involving coincidence detection of a charged fragment and a neutron both emitted at forward angles is employed to map the energy spectrum above the neutron decay threshold. Several resonance structures are revealed in the invariant mass spectra, and the nature for some of them is discussed from comparisons of differential cross section data with predictions of microscopic DWBA calculations based on spsdp f shell model wave functions and a recent parametrization of semi-microscopic nucleon-nucleus optical model potential (JLMB). By extrapolating the (p, n) cross sections leading to the 1(+) state at 1.27 MeV in (14)B to zero momentum transfer the Gamow-Teller transition strength is deduced. The value is found to compare well with that reported in a beta-delayed neutron emission study.

Published
2011

47. Channel selection of neutron-rich nuclei following fusion-evaporation reactions of light systems

Author

L. A. Bernstein, S. R. Lesher, A. O. Macchiavelli, J. Pavan, M. Wiedeking, Jason Burke, M. A. Deleplanque, M. Cromaz, L.G. Moretto, Elena Rodriguez-Vieitez, H. B. Jeppesen, R. M. Clark, B.F. Goldblum, M. A. McMahan, J. Gibelin, I. Y. Lee, D. L. Bleuel, P. T. Lake, S. Basunia, L. W. Phair, S. Gros, Nicholas Scielzo, and P. Fallon

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, SIMPLE (dark matter experiment), Fusion, Projectile, Nuclear structure, Neutron, Spectroscopy, Instrumentation, Measure (mathematics), Coincidence
Abstract

Experimental results for the minor decay channels of fusion-evaporation in light projectile plus light target systems are presented. These new data were obtained during test campaigns to measure the opening of different decay channels. Experiments were designed to provide relative cross-section information on weakly populated channels for gamma-ray spectroscopy experiments in coincidence with charged-particles. The results are compared to publicly available fusion-evaporation codes. The data follow a simple estimate which is useful in predicting experimental conditions to make the fusion-evaporation reaction a viable nuclear structure tool to study weakly populated light neutron-rich nuclei.

Published
2011

48. Gamma-ray multiplicity measurement of the spontaneous fission of 252Cf in a segmented HPGe/BGO detector array

Author

Eric B. Norman, M. Heffner, Jason Burke, M. A. Stoyer, D. L. Bleuel, Nicholas Scielzo, L. W. Phair, J. Gibelin, M. Wiedeking, Steven Sheets, N J Snyderman, L. A. Bernstein, and J. Mintz

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Fission, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Semiconductor detector, Nuclear physics, Neutron, Multiplicity (chemistry), Nuclear Experiment, Instrumentation, Radioactive decay, Spontaneous fission
Abstract

Coincident γ rays from a 252Cf source were measured using an array of six segmented high-purity germanium (HPGe) Clover detectors each enclosed by 16 bismuth-germanate (BGO) detectors. The detectors were arranged in a cubic pattern around a 1 μ Ci 252Cf source to cover a large solid angle for γ ‐ray measurement with a reasonable reconstruction of the multiplicity. Neutron multiplicity was determined in certain cases by identifying the prompt γ rays from individual fission fragment pairs. Multiplicity distributions from previous experiments and theoretical models were convolved with the response function of the array and compared to the present results. These results suggest a γ ‐ray multiplicity spectrum broader than previous measurements and models, and provide no evidence of correlation with neutron multiplicity.

Published
2010

49. STARS/LiBerACE: Segmented silicon and high-purity germanium detector arrays for low-energy nuclear reaction and structure studies

Author

P. Fallon, L. W. Phair, Nicholas Scielzo, J. Gibelin, J. A. Church, Jason Burke, S. R. Lesher, M. Wiedeking, D. L. Bleuel, and L. A. Bernstein

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Silicon, Physics::Instrumentation and Detectors, Fission, business.industry, Detector, chemistry.chemical_element, Germanium, Semiconductor detector, law.invention, Nuclear physics, Telescope, Stars, Optics, chemistry, law, High Energy Physics::Experiment, Nuclear Experiment, business, Instrumentation
Abstract

The Silicon Telescope Array for Reaction Studies (STARS) consists of large-area annular double-sided silicon detectors for charged-particle identification. The Livermore Berkeley Array for Collaborative Experiments (LiBerACE) is an array of six Compton-suppressed high-purity germanium Clover detectors for efficient detection of γ-rays. These detector arrays are versatile tools for studies of neutron-induced reaction cross-sections, fission, light neutron-rich nuclei, and other low-energy nuclear physics topics through transfer, fusion, incomplete-fusion, and inelastic-scattering reactions. The STARS and LiBerACE arrays and typical experimental configurations are described in detail.

Published
2010

50. The (3He,tf) as a surrogate reaction to determine (n,f) cross sections in the 10–20MeV energy range

Author

Bethany L. Goldblum, L. A. Bernstein, J. Gibelin, R. M. Clark, Robert Hatarik, Elena Rodriguez-Vieitez, M. A. McMahan, D. L. Bleuel, F. S. Dietrich, S. R. Lesher, C.C. Jewett, Jason Burke, B. Darakchieva, C. W. Beausang, M. S. Basunia, P. Fallon, L. W. Phair, M. Wiedeking, and M. Evtimova

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Silicon, Fission, Cyclotron, Nuclear data, chemistry.chemical_element, Charged particle, Neutron temperature, law.invention, Nuclear physics, Cross section (physics), chemistry, law, Instrumentation
Abstract

The surrogate reaction 238 U( 3 He, tf ) is used to determine the 237 Np( n , f ) cross section indirectly over an equivalent neutron energy range from 10 to 20 MeV. A self-supporting ∼761 μg/cm 2 metallic 238 U foil was bombarded with a 42 MeV 3 He 2+ beam from the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory (LBNL). Outgoing charged particles and fission fragments were identified using the Silicon Telescope Array for Reaction Studies (STARS) consisted of two 140 μm and one 1000 μm Micron S2 type silicon detectors. The 237 Np( n , f ) cross sections, determined indirectly, were compared with the 237 Np( n , f ) cross section data from direct measurements, the Evaluated Nuclear Data File (ENDF/B-VII.0), and the Japanese Evaluated Nuclear Data Library (JENDL 3.3) and found to closely follow those datasets. Use of the ( 3 He, tf ) reaction as a surrogate to extract ( n , f ) cross sections in the 10–20 MeV equivalent neutron energy range is found to be suitable.

Published
2009

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