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58 results on '"G. Authelet"'

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. 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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3. Spectroscopy of 2565,67Mn: Strong coupling in the N = 40 'island of inversion'

Author

X.Y. Liu, Z. Liu, B. Ding, P. Doornenbal, A. Obertelli, S.M. Lenzi, P.M. Walker, L.X. Chung, B.D. Linh, G. Authelet, H. Baba, D. Calvet, F. Château, A. Corsi, A. Delbart, J.-M. Gheller, A. Gillibert, T. Isobe, V. Lapoux, M. Matsushita, S. Momiyama, T. Motobayashi, M. Niikura, F. Nowacki, H. Otsu, C. Péron, A. Peyaud, E.C. Pollacco, J.-Y. Roussé, H. Sakurai, M. Sasano, Y. Shiga, S. Takeuchi, R. Taniuchi, T. Uesaka, H. Wang, K. Yoneda, Y.H. Lam, T.H. Huang, M.D. Sun, W.Q. Zhang, H.Y. Lu, D.S. Hou, F. Browne, Zs. Dombradi, S. Franchoo, F. Giacoppo, A. Gottardo, K. Hadynska-Klek, Z. Korkulu, S. Koyama, Y. Kubota, J. Lee, M. Lettmann, R. Lozeva, K. Matsui, T. Miyazaki, S. Nishimura, C. Louchart, L. Olivier, S. Ota, Z. Patel, E. Sahin, C. Santamaria, C. Shand, P.-A. Söderström, G.L. Stefan, D. Steppenbeck, T. Sumikama, D. Suzuki, Zs. Vajta, V. Werner, J. Wu, Z. Xu, X.H. Zhou, Y.H. Zhang, H.S. Xu, and F.S. Zhang

Subjects
Physics, QC1-999
Abstract

Excited states in 63,65,67Mn were studied via in-beam γ-ray spectroscopy following knockout reactions from 68Fe. Similar level schemes, consisting of the 11/2−, 9/2−, 7/2− and 5/2g.s.− level sequence, connected by I→I−1 transitions, were established, the first time for 65,67Mn. Their level structures show features consistent with strongly-coupled rotational bands with K=5/2. State-of-the-art shell-model calculations with the modified LNPS effective interaction reproduce the observed levels remarkably well and suggest the dominance of 4-particle-4-hole neutron configurations for all the states. The data on the low-lying excited states of odd-mass 53−67Mn provide a textbook example of nuclear structure evolution from weak coupling through decoupling to strong coupling along a single isotopic chain on the n-rich side of the β stability line. These results help to deepen our understanding of the N=40 “island of inversion”. Keywords: In-beam γ-ray spectroscopy, “Island of inversion” around N=40, Strong coupling, Structure evolution

Published
2018
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4. Shell evolution beyond Z=28 and N=50: Spectroscopy of 81,82,83,84Zn

Author

C.M. Shand, Zs. Podolyák, M. Górska, P. Doornenbal, A. Obertelli, F. Nowacki, T. Otsuka, K. Sieja, J.A. Tostevin, Y. Tsunoda, G. Authelet, H. Baba, D. Calvet, A. Château, S. Chen, A. Corsi, A. Delbart, J.M. Gheller, A. Giganon, A. Gillibert, T. Isobe, V. Lapoux, M. Matsushita, S. Momiyama, T. Motobayashi, M. Niikura, H. Otsu, N. Paul, C. Péron, A. Peyaud, E.C. Pollacco, J.-Y. Roussé, H. Sakurai, C. Santamaria, M. Sasano, Y. Shiga, D. Steppenbeck, S. Takeuchi, R. Taniuchi, T. Uesaka, H. Wang, K. Yoneda, T. Ando, T. Arici, A. Blazhev, F. Browne, A.M. Bruce, R.J. Carroll, L.X. Chung, M.L. Cortés, M. Dewald, B. Ding, Zs. Dombrádi, F. Flavigny, S. Franchoo, F. Giacoppo, A. Gottardo, K. Hadyńska-Klęk, A. Jungclaus, Z. Korkulu, S. Koyama, Y. Kubota, J. Lee, M. Lettmann, B.D. Linh, J. Liu, Z. Liu, C. Lizarazo, C. Louchart, R. Lozeva, K. Matsui, T. Miyazaki, K. Moschner, M. Nagamine, N. Nakatsuka, S. Nishimura, C.R. Nita, C.R. Nobs, L. Olivier, S. Ota, R. Orlandi, Z. Patel, P.H. Regan, M. Rudigier, E. Şahin, T. Saito, P.-A. Söderström, I. Stefan, T. Sumikama, D. Suzuki, Zs. Vajta, V. Vaquero, V. Werner, K. Wimmer, J. Wu, and Z.Y. Xu

Subjects
Physics, QC1-999
Abstract

We report on the measurement of new low-lying states in the neutron-rich 81,82,83,84Zn nuclei via in-beam γ-ray spectroscopy. These include the 41+→21+ transition in 82Zn, the 21+→0g.s.+ and 41+→21+ transitions in 84Zn, and low-lying states in 81,83Zn were observed for the first time. The reduced E(21+) energies and increased E(41+)/E(2+1) ratios at N=52, 54 compared to those in 80Zn attest that the magicity is confined to the neutron number N=50 only. The deduced level schemes are compared to three state-of-the-art shell model calculations and a good agreement is observed with all three calculations. The newly observed 2+ and 4+ levels in 84Zn suggest the onset of deformation towards heavier Zn isotopes, which has been incorporated by taking into account the upper sdg orbitals in the Ni78-II and the PFSDG-U models.

Published
2017
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5. 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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6. γ -ray spectroscopy of low-lying yrast and non-yrast states in neutron-rich Kr94,95,96

Author

R.-B. Gerst, A. Blazhev, K. Moschner, P. Doornenbal, A. Obertelli, K. Nomura, J.-P. Ebran, S. Hilaire, J. Libert, G. Authelet, H. Baba, D. Calvet, F. Château, S. Chen, A. Corsi, A. Delbart, J.-M. Gheller, A. Giganon, A. Gillibert, V. Lapoux, T. Motobayashi, M. Niikura, N. Paul, J.-Y. Roussé, H. Sakurai, C. Santamaria, D. Steppenbeck, R. Taniuchi, T. Uesaka, T. Ando, T. Arici, F. Browne, A. M. Bruce, R. Caroll, L. X. Chung, M. L. Cortés, M. Dewald, B. Ding, F. Flavigny, S. Franchoo, M. Górska, A. Gottardo, J. Jolie, A. Jungclaus, J. Lee, M. Lettmann, B. D. Linh, J. Liu, Z. Liu, C. Lizarazo, S. Momiyama, S. Nagamine, N. Nakatsuka, C. R. Nita, C. Nobs, L. Olivier, R. Orlandi, Z. Patel, Zs. Podolyák, M. Rudigier, T. Saito, C. Shand, P.-A. Söderström, I. Stefan, V. Vaquero, V. Werner, K. Wimmer, and Z. Xu

Published
2022

7. 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

8. 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

9. Surface Localization of the Dineutron in Li11

Author

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

Subjects
Surface (mathematics), Physics, Nuclear Theory, General Physics and Astronomy, Nuclear matter, 7. Clean energy, 01 natural sciences, Nuclear physics, Momentum, medicine.anatomical_structure, 0103 physical sciences, medicine, Neutron, Nuclear Experiment, 010306 general physics, Nucleon, Nucleus
Abstract

The formation of a dineutron in the nucleus $^{11}$Li is found to be localized to the surface region. The experiment measured the intrinsic momentum of the struck neutron in $^{11}$Li via the $(p,pn)$ knockout reaction at 246 MeV/nucleon. The correlation angle between the two neutrons is, for the first time, measured as a function of the intrinsic neutron momentum. A comparison with reaction calculations reveals the localization of the dineutron at $r\sim3.6$ fm. The results also support the density dependence of dineutron formation as deduced from Hartree-Fock-Bogoliubov calculations for nuclear matter.

Published
2020

10. Experimental investigation of vertical neon pulsating heat pipe for superconducting magnet cooling application

Author

T Dixit, G Authelet, C Mailleret, F Gouit, and B Baudouy

Abstract

Pulsating heat pipes (PHPs) are two-phase flow, thermal transport carriers characterized by ease of fabrication, flexibility of compactness and variable heat transfer capability. Conventionally, cooling of superconducting magnets is realized by using cryogen cooling system. Cryogenic PHPs are emerging as the new-age economical alternative that can passively contribute in efficient transport of generated heat to active cryocoolers. Nevertheless, a number of challenges must be addressed to materialize this union. For this objective, a multipurpose experimental test-rig has been developed which will allow different critical parameters of cryogenic PHPs to be investigated. The preliminary tests are conducted using neon as the working fluid. The PHP capillaries, made of SS304, have an outer diameter of 2.5 mm and a projected length of 400 mm with the adiabatic part having twice the length as compared to that in the condenser and evaporator. It consists of 20 parallel tubes forming a closed-loop and are tested in gravity-assisted environment. Employing the Sumitomo RDE-418D4 4K Cryocooler, the condenser temperature is controlled at the neon saturation temperature, around 27 K. The thermal performance of this cryogenic PHP is recorded at different evaporator heat load conditions. We report here the temperature evolution of PHP evaporator, and condenser as well as the pressure oscillations with time.

Published
2022

11. Sequential Nature of (p,3p) Two-Proton Knockout from Neutron-Rich Nuclei

Author

Megumi Niikura, K. Yoneda, Tomohiro Uesaka, T. Miyazaki, J.-Y. Roussé, A. Jungclaus, I. G. Stefan, Masaki Sasano, A. Gillibert, Jian Liu, Hiroyoshi Sakurai, David Steppenbeck, Zs. Dombradi, K. Moschner, M. Gómez-Ramos, Satoshi Takeuchi, D. Calvet, T. Isobe, Shunji Nishimura, T. Saito, V. Lapoux, H. Wang, T. Motobayashi, L. Olivier, R. Lozeva, A. Gottardo, S. Franchoo, C. Péron, H. Baba, Jinguang Wu, G. Authelet, A. Delbart, A. Blazhev, J. M. Gheller, Hideaki Otsu, F. Château, Masafumi Matsushita, Zs. Vajta, Zena Patel, Victor Vaquero, Kathrin Wimmer, M. L. Cortés, K. Matsui, Shuichi Ota, C. Santamaria, E. C. Pollacco, M. Dewald, Alessandra Corsi, F. Browne, C. R. Nita, M. Rudigier, Z. Korkulu, Jenny Lee, Yoshiaki Shiga, K. Hadynska-Klek, S. Nagamine, Satoru Momiyama, A. Frotscher, T. Arici, Ryo Taniuchi, Noritaka Shimizu, C. R. Nobs, Toshiyuki Sumikama, Alison Bruce, C. Louchart, E. Sahin, Toshiaki Ando, Zhenci Xu, F. Giacoppo, Y. Kubota, L. X. Chung, B. D. Linh, P. Doornenbal, F. Flavigny, A. Giganon, N. Paul, C. M. Shand, Noritsugu Nakatsuka, Zi Hong Liu, V. Werner, M. Górska, Si-Ge Chen, P. A. Söderström, D. Suzuki, M. Lettmann, R. Orlandi, C. Lizarazo, A. Obertelli, Raymond J. Carroll, Bing Ding, Zs. Podolyák, Shoko Koyama, and Alan Peyaud

Subjects
Physics, Hydrogen, Proton, Projectile, Nuclear Theory, General Physics and Astronomy, chemistry.chemical_element, 01 natural sciences, Coincidence, Nuclear physics, medicine.anatomical_structure, chemistry, MINOS, 0103 physical sciences, medicine, Neutron, Nuclear Experiment, 010306 general physics, Nucleon, Nucleus
Abstract

Twenty-one two-proton knockout (p; 3p) cross sections from neutron-rich nuclei at ~ 250 MeV/nucleon were measured. For the first time, the angular distribution of the three emitted protons were measured in coincidence with the tracker and hydrogen target MINOS, demonstrating that the (p; 3p) kinematics is consistent with two sequential proton-proton collisions within the projectile nucleus. Ratios of (p; 3p) over (p; 2p) inclusive cross sections follow the trend of other many-proton (neutron) removal reactions, further reinforcing the sequential nature of (p; 3p) in neutron-rich nuclei.

Published
2020

12. Metastable States of Se92,94 : Identification of an Oblate K Isomer of Se94 and the Ground-State Shape Transition between N=58 and 60

Author

L. Olivier, I. Kojouharov, G. Authelet, J. M. Gheller, V. Lapoux, Jenny Lee, J.-Y. Roussé, J. Gerl, C. Lizarazo, N. Paul, Noritsugu Nakatsuka, Hiroyoshi Sakurai, H. Schaffner, P. M. Walker, Zi Hong Liu, V. Werner, David Steppenbeck, T. Motobayashi, A. Blazhev, P. Doornenbal, Shunji Nishimura, I. Stefan, M. L. Cortés, T. Arici, J. J. Liu, Tomás R. Rodríguez, Alison Bruce, A. Giganon, C. Santamaria, F. Château, Megumi Niikura, Zhengyu Xu, F. Browne, Tomohiro Uesaka, M. Rudigier, C. R. Niţă, P. A. Söderström, Zena Patel, T. Saito, N. Kurz, M. Górska, S. Franchoo, A. Gillibert, G. X. Dong, A. Gottardo, C. M. Shand, Satoru Momiyama, L. X. Chung, C. R. Nobs, B. D. Linh, S. Nagamine, Ryo Taniuchi, A. Obertelli, M. Dewald, K. Moschner, Kathrin Wimmer, H. Baba, R. J. Caroll, D. Calvet, F. Flavigny, Bing Ding, Zs. Podolyák, Furong Xu, Toshiaki Ando, Si-Ge Chen, Victor Vaquero, M. Lettmann, A. Corsi, Norbert Pietralla, and A. Delbart

Subjects
Physics, 010308 nuclear & particles physics, General Physics and Astronomy, chemistry.chemical_element, Germanium, 01 natural sciences, Hafnium, medicine.anatomical_structure, chemistry, Atomic orbital, Metastability, 0103 physical sciences, Physics::Atomic and Molecular Clusters, medicine, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Ground state, Spectroscopy, Nucleus
Abstract

Here we present new information on the shape evolution of the very neutron-rich ^{92,94}Se nuclei from an isomer-decay spectroscopy experiment at the Radioactive Isotope Beam Factory at RIKEN. High-resolution germanium detectors were used to identify delayed γ rays emitted following the decay of their isomers. New transitions are reported extending the previously known level schemes. The isomeric levels are interpreted as originating from high-K quasineutron states with an oblate deformation of β∼0.25, with the high-K state in ^{94}Se being metastable and K hindered. Following this, ^{94}Se is the lowest-mass neutron-rich nucleus known to date with such a substantial K hindrance. Furthermore, it is the first observation of an oblate K isomer in a deformed nucleus. This opens up the possibility for a new region of K isomers at low Z and at oblate deformation, involving the same neutron orbitals as the prolate orbitals within the classic Z∼72 deformed hafnium region. From an interpretation of the level scheme guided by theoretical calculations, an oblate deformation is also suggested for the ^{94}Se_{60} ground-state band.

Published
2020

13. Metastable States of ^{92,94}Se: Identification of an Oblate K Isomer of ^{94}Se and the Ground-State Shape Transition between N=58 and 60

Author

C, Lizarazo, P-A, Söderström, V, Werner, N, Pietralla, P M, Walker, G X, Dong, F R, Xu, T R, Rodríguez, F, Browne, P, Doornenbal, S, Nishimura, C R, Niţă, A, Obertelli, T, Ando, T, Arici, G, Authelet, H, Baba, A, Blazhev, A M, Bruce, D, Calvet, R J, Caroll, F, Château, S, Chen, L X, Chung, A, Corsi, M L, Cortés, A, Delbart, M, Dewald, B, Ding, F, Flavigny, S, Franchoo, J, Gerl, J-M, Gheller, A, Giganon, A, Gillibert, M, Górska, A, Gottardo, I, Kojouharov, N, Kurz, V, Lapoux, J, Lee, M, Lettmann, B D, Linh, J J, Liu, Z, Liu, S, Momiyama, K, Moschner, T, Motobayashi, S, Nagamine, N, Nakatsuka, M, Niikura, C, Nobs, L, Olivier, Z, Patel, N, Paul, Zs, Podolyák, J-Y, Roussé, M, Rudigier, T Y, Saito, H, Sakurai, C, Santamaria, H, Schaffner, C, Shand, I, Stefan, D, Steppenbeck, R, Taniuchi, T, Uesaka, V, Vaquero, K, Wimmer, and Z, Xu

Abstract

Here we present new information on the shape evolution of the very neutron-rich ^{92,94}Se nuclei from an isomer-decay spectroscopy experiment at the Radioactive Isotope Beam Factory at RIKEN. High-resolution germanium detectors were used to identify delayed γ rays emitted following the decay of their isomers. New transitions are reported extending the previously known level schemes. The isomeric levels are interpreted as originating from high-K quasineutron states with an oblate deformation of β∼0.25, with the high-K state in ^{94}Se being metastable and K hindered. Following this, ^{94}Se is the lowest-mass neutron-rich nucleus known to date with such a substantial K hindrance. Furthermore, it is the first observation of an oblate K isomer in a deformed nucleus. This opens up the possibility for a new region of K isomers at low Z and at oblate deformation, involving the same neutron orbitals as the prolate orbitals within the classic Z∼72 deformed hafnium region. From an interpretation of the level scheme guided by theoretical calculations, an oblate deformation is also suggested for the ^{94}Se_{60} ground-state band.

Published
2020

14. Shell structure of the neutron-rich isotopes Co69,71,73

Author

M. Lettmann, A. Gillibert, Alessandra Corsi, David Steppenbeck, S. Leblond, Yoshiaki Shiga, K. Yoshida, Toshiyuki Sumikama, Ryo Taniuchi, A. Gottardo, F. Nowacki, Jenny Lee, V. Lapoux, Yuya Kubota, C. Péron, A. Delbart, Shunji Nishimura, G. Authelet, Si-Ge Chen, P. A. Söderström, C. Louchart, J. M. Gheller, T. Miyazaki, Alan Peyaud, C. M. Shand, Satoshi Takeuchi, Masafumi Matsushita, F. Giacoppo, H. Baba, Satoru Momiyama, S. Franchoo, E. Sahin, Zhenci Xu, Jinguang Wu, Shuichi Ota, V. Werner, Hideaki Otsu, Alfredo Poves, L. X. Chung, Megumi Niikura, C. Santamaria, Tomohiro Uesaka, I. Stefan, K. Matsui, P. Doornenbal, Kazuyuki Ogata, F. Browne, Masaki Sasano, Zs. Dombrádi, Shoko Koyama, Z. Korkulu, Zs. Vajta, K. Hadynska-Klek, T. Lokotko, Z. Patel, L. Olivier, H. Wang, R. Lozeva, A. Obertelli, Hiroyoshi Sakurai, T. Motobayashi, E. C. Pollacco, J.-Y. Roussé, D. Calvet, T. Isobe, F. Château, and Daisuke Suzuki

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Nuclear structure, Impulse (physics), 7. Clean energy, 01 natural sciences, Coincidence, Nuclear physics, MINOS, 0103 physical sciences, Neutron, Detector array, Nuclear Experiment, 010306 general physics, Excitation
Abstract

The structures of the neutron-rich Co69,71,73 isotopes were investigated via (p,2p) knockout reactions at the Radioactive Isotope Beam Factory, RIKEN. Isotopes of interest were studied using the DALI2 γ-ray detector array combined with the MINOS target and tracker system. Level schemes were reconstructed using the γ-γ coincidence technique, with tentative spin-parity assignments based on the measured inclusive and exclusive cross sections. Comparison with shell-model calculations using the Lenzi-Nowacki-Poves-Sieja LNPS and PFSDG-U interactions suggests coexistence of spherical and deformed shapes at low excitation energies in the Co69,71,73 isotopes. The distorted-wave impulse approximation (DWIA) framework was used to calculate the single-particle cross sections. These values were compared with the experimental findings.

Published
2020

15. 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

16. Spectroscopy of 2565,67Mn: Strong coupling in the N = 40 'island of inversion'

Author

K. Matsui, H. Otsu, W.Q. Zhang, J.-Y. Roussé, Tadaaki Isobe, R. Lozeva, X.H. Zhou, Satoshi Takeuchi, X.Y. Liu, E. Sahin, Shunpei Koyama, P. Doornenbal, S. Franchoo, Zs. Dombradi, F. Nowacki, Shuichi Ota, C. Santamaria, A. Obertelli, A. Gottardo, Daisuke Suzuki, K. Hadynska-Klek, Jin Wu, L. X. Chung, Masaki Sasano, Ryo Taniuchi, Hiroyoshi Sakurai, Jenny Lee, K. Yoneda, Megumi Niikura, H.S. Xu, P. A. Söderström, C. Louchart, T. Motobayashi, Tomohiro Uesaka, Yuya Kubota, C. Péron, Tsuyoshi Miyazaki, H. Lu, G. Authelet, G. L. Stefan, V. Werner, B. D. Linh, F. Château, A. Delbart, J. M. Gheller, A. Gillibert, C. M. Shand, H. Wang, Z. Liu, S. Nishimura, Zs. Vajta, Philip M Walker, Masafumi Matsushita, Satoru Momiyama, M. Lettmann, F. Browne, S. M. Lenzi, Yoshiaki Shiga, Toshiyuki Sumikama, L. Olivier, E. C. Pollacco, Feng-Shou Zhang, F. Giacoppo, David Steppenbeck, V. Lapoux, T.H. Huang, Zena Patel, H. Baba, M. D. Sun, Y.H. Zhang, D. Calvet, Zhengyu Xu, Alan Peyaud, B. Ding, A. Corsi, Z. Korkulu, Y.H. Lam, and De-fu Hou

Subjects
Physics, Coupling, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Island of inversion, Nuclear structure, Decoupling (cosmology), 01 natural sciences, Molecular physics, Excited state, 0103 physical sciences, Neutron, 010306 general physics, Spectroscopy, Line (formation)
Abstract

Excited states in 63,65,67Mn were studied via in-beam γ-ray spectroscopy following knockout reactions from 68Fe. Similar level schemes, consisting of the 11/2−, 9/2−, 7/2− and 5/2 g.s.− level sequence, connected by I→I−1 transitions, were established, the first time for 65,67Mn. Their level structures show features consistent with strongly-coupled rotational bands with K=5/2 . State-of-the-art shell-model calculations with the modified LNPS effective interaction reproduce the observed levels remarkably well and suggest the dominance of 4-particle-4-hole neutron configurations for all the states. The data on the low-lying excited states of odd-mass 53−67Mn provide a textbook example of nuclear structure evolution from weak coupling through decoupling to strong coupling along a single isotopic chain on the n-rich side of the β stability line. These results help to deepen our understanding of the N=40 “island of inversion”.

Published
2018

17. Shell evolution beyond Z = 28 and N = 50: Spectroscopy of 81,82,83,84 Zn

Author

L. Olivier, K. Moschner, Kathrin Wimmer, E. C. Pollacco, A. Gillibert, C. R. Nita, C. M. Shand, J.-Y. Roussé, Satoru Momiyama, M. Lettmann, Jian Liu, A. Jungclaus, Hideaki Otsu, Z. Korkulu, Ryo Taniuchi, C. Péron, David Steppenbeck, A. Blazhev, Tsuyoshi Miyazaki, G. Authelet, K. Matsui, Satoshi Takeuchi, A. Château, A. Obertelli, F. Nowacki, S. Franchoo, Kamila Sieja, Toshiaki Ando, J. M. Gheller, Alan Peyaud, Jin Wu, L. X. Chung, Shuichi Ota, C. R. Nobs, B. D. Linh, Zs. Vajta, Y. Kubota, Megumi Niikura, M. Rudigier, I. Stefan, H. Wang, R. Orlandi, J. A. Tostevin, Takaharu Otsuka, Si-Ge Chen, P. A. Söderström, Tomohiro Uesaka, C. Lizarazo, S. Nishimura, Zs. Dombradi, Toshiyuki Sumikama, K. Hadynska-Klek, M. Nagamine, Yusuke Tsunoda, T. Isobe, E. Sahin, C. Louchart, Hiroyoshi Sakurai, V. Lapoux, C. Santamaria, T. Motobayashi, Victor Vaquero, F. Giacoppo, T. Arici, A. Corsi, Zena Patel, P. Doornenbal, Masafumi Matsushita, A. Delbart, P. H. Regan, M. Dewald, Zsolt Podolyak, A. Giganon, A. Gottardo, Jenny Lee, F. Flavigny, M. Górska, N. Paul, Noritsugu Nakatsuka, M. L. Cortés, Zi Hong Liu, V. Werner, Raymond J. Carroll, Daisuke Suzuki, D. Calvet, M. Sasano, Bing Ding, Shoko Koyama, Zhengyu Xu, T. Saito, Alison Bruce, R. Lozeva, K. Yoneda, F. Browne, H. Baba, Yoshiaki Shiga, SCOAP, RIKEN Nishina Center for Accelerator-Based Science, Science and Technology Facilities Council (UK), European Commission, European Research Council, Vietnam Academy of Science and Technology, Federal Ministry of Education and Research (Germany), Ministerio de Economía y Competitividad (España), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Isotope, 010308 nuclear & particles physics, SHELL model, Analytical chemistry, Shell (structure), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, lcsh:QC1-999, Atomic orbital, Neutron number, 0103 physical sciences, ddc:530, Atomic physics, 010306 general physics, Spectroscopy, lcsh:Physics
Abstract

C.M. Shand et al. -- 6 pags., 3 figs., tab. --Open Access funded by Creative Commons Atribution Licence 4.0, We report on the measurement of new low-lying states in the neutron-rich Zn nuclei via in-beam γ-ray spectroscopy. These include the 4 →2 transition in Zn, the 2 →0 and 4 →2 transitions in Zn, and low-lying states in Zn were observed for the first time. The reduced E(2 ) energies and increased E(4 )/E(2 ) ratios at N=52, 54 compared to those in Zn attest that the magicity is confined to the neutron number N=50 only. The deduced level schemes are compared to three state-of-the-art shell model calculations and a good agreement is observed with all three calculations. The newly observed 2 and 4 levels in Zn suggest the onset of deformation towards heavier Zn isotopes, which has been incorporated by taking into account the upper sdg orbitals in the Ni78-II and the PFSDG-U models., All UK authors are supported by the Science and Technology Facilities Council (STFC). The development of MINOS and the core MINOS team have been supported by the European Research Council through the ERC Grant No. MINOS-258567. A. Jungclaus was supported by the Spanish Ministerio de Economía y Competitividad under contract FPA2014-57196-C5-4-P. Authors from Cologne were supported by German BMBF Grant No. 05P15PKFNA. Authors from TU Darmstadt were supported by German BMBF Grant No. 05P12RDFN8 and 05P15RDFN1. L.X. Chung and B.D. Linh would like to acknowledge Vietnam Ministry of Science and Technology for the support, and Radioactive Isotope Physics Laboratory of the RIKEN Nishina Center for supporting their stay during the experiments.

Published
2017

18. Prominence of Pairing in Inclusive (p,2p) and (p,pn) Cross Sections from Neutron-Rich Nuclei

Author

A. Corsi, V. Lapoux, Zs. Dombradi, K. Matsui, David Steppenbeck, A. Gillibert, Alan Peyaud, Shoko Koyama, Toshiaki Ando, C. M. Shand, Hiroyoshi Sakurai, M. Rudigier, F. Browne, L. Olivier, Raymond J. Carroll, K. Yoneda, E. Sahin, Yoshiaki Shiga, Bing Ding, F. Château, Pieter Doornenbal, Hidetada Baba, Tomoyuki Saito, Tohru Motobayashi, Zs. Podolyák, Satoru Momiyama, F. Giacoppo, C. R. Nita, T. Sumikama, H. Wang, Megumi Niikura, A. Gottardo, Jenny Lee, M. Dewald, Zs. Vajta, R. Orlandi, Shuichi Ota, E. C. Pollacco, K. Hadynska-Klek, F. Flavigny, P. A. Söderström, Daisuke Suzuki, Yuya Kubota, C. Lizarazo, D. Calvet, S. Nagamine, C. Péron, Tomohiro Uesaka, R. Lozeva, Hideaki Otsu, N. Paul, Shenjian Chen, G. Authelet, Noritsugu Nakatsuka, Ryo Taniuchi, A. Delbart, Carlos A. Bertulani, J. M. Gheller, Zi Hong Liu, V. Werner, T. Arici, M. Matsushita, Masaki Sasano, M. Lettmann, B. D. Linh, C. Santamaria, Alison Bruce, J. L. Rodriguez-Sanchez, Satoshi Takeuchi, I. Stefan, M. Górska, S. Franchoo, C. Louchart, Zhengyu Xu, Zena Patel, J.-Y. Roussé, Tadaaki Isobe, S. Nishimura, A. Jungclaus, Victor Vaquero, T. Miyazaki, M. L. Cortés, A. Obertelli, K. Moschner, Kathrin Wimmer, Z. Korkulu, Jin Wu, L. X. Chung, C. R. Nobs, Jian Liu, A. Blazhev, and A. Giganon

Subjects
Physics, Hydrogen, Proton, Nuclear Theory, General Physics and Astronomy, chemistry.chemical_element, 01 natural sciences, 7. Clean energy, Nuclear physics, chemistry, Cascade, Pairing, 0103 physical sciences, Bound state, Physics::Accelerator Physics, Neutron, Nuclear Experiment, 010306 general physics, Nucleon, Beam (structure)
Abstract

Fifty-five inclusive single nucleon removal cross sections from medium mass neutron-rich nuclei impinging on a hydrogen target at � 250 MeV/nucleon were measured at the RIKEN Radioactive Isotope Beam Factory. Systematically higher cross sections are found for proton removal from nuclei with an even number of protons compared to odd-proton number projectiles for a given neutron separation energy. Neutron removal cross sections display no even-odd splitting contrary to nuclear cascade model predictions. Both effects are understood through simple considerations of neutron separation energies and bound state level densities originating in pairing correlations in the daughter nuclei. These conclusions are supported by comparison with semi-microscopic model predictions,highlighting the enhanced role of low-lying level densities in nucleon removal cross sections from loosely-bound nuclei.

Published
2019

19. Prominence of Pairing in Inclusive (p,2p) and (p,pn) Cross Sections from Neutron-Rich Nuclei

Author

N, Paul, A, Obertelli, C A, Bertulani, A, Corsi, P, Doornenbal, J L, Rodriguez-Sanchez, G, Authelet, H, Baba, D, Calvet, F, Château, S, Chen, A, Delbart, J-M, Gheller, A, Giganon, A, Gillibert, T, Isobe, V, Lapoux, M, Matsushita, S, Momiyama, T, Motobayashi, M, Niikura, H, Otsu, C, Péron, A, Peyaud, E C, Pollacco, J-Y, Roussé, H, Sakurai, C, Santamaria, M, Sasano, Y, Shiga, D, Steppenbeck, S, Takeuchi, R, Taniuchi, T, Uesaka, H, Wang, K, Yoneda, T, Ando, T, Arici, A, Blazhev, F, Browne, A M, Bruce, R, Carroll, L X, Chung, M L, Cortés, M, Dewald, B, Ding, Zs, Dombradi, F, Flavigny, S, Franchoo, F, Giacoppo, M, Górska, A, Gottardo, K, Hadynska-Klek, Z, Korkulu, S, Koyama, Y, Kubota, A, Jungclaus, J, Lee, M, Lettmann, B D, Linh, J, Liu, Z, Liu, C, Lizarazo, C, Louchart, R, Lozeva, K, Matsui, T, Miyazaki, K, Moschner, S, Nagamine, N, Nakatsuka, C, Nita, S, Nishimura, C R, Nobs, L, Olivier, S, Ota, Z, Patel, Zs, Podolyák, M, Rudigier, E, Sahin, T Y, Saito, C, Shand, P-A, Söderström, I G, Stefan, T, Sumikama, D, Suzuki, R, Orlandi, V, Vaquero, Zs, Vajta, V, Werner, K, Wimmer, J, Wu, and Z, Xu

Subjects
Nuclear Theory, Physics::Accelerator Physics, Nuclear Experiment
Abstract

Fifty-five inclusive single nucleon-removal cross sections from medium mass neutron-rich nuclei impinging on a hydrogen target at ∼ 250 MeV / nucleon are measured at the RIKEN Radioactive Isotope Beam Factory. Systematically higher cross sections are found for proton removal from nuclei with an even number of protons as compared to odd-proton number projectiles for a given neutron separation energy. Neutron removal cross sections display no even-odd splitting, contrary to nuclear cascade model predictions. Both effects are understood through simple considerations of neutron separation energies and bound state level densities originating in pairing correlations in the daughter nuclei. These conclusions are supported by comparison with semimicroscopic model predictions, highlighting the enhanced role of low-lying level densities in nucleon-removal cross sections from loosely bound nuclei.

Published
2019

20. Nuclear structure of Ni76 from the ( p,2p ) reaction

Author

Kamila Sieja, L. Olivier, Shuichi Ota, H. Wang, Ryo Taniuchi, C. Santamaria, P. A. Söderström, Z. Patel, A. Gillibert, K. Yoneda, E. Sahin, V. Lapoux, Zhenci Xu, R. Lozeva, Kazuyuki Ogata, Jinguang Wu, David Steppenbeck, C. M. Shand, P. Doornenbal, Z. Elekes, Megumi Niikura, K. Hadynska-Klek, Á. Kripkó, Tomohiro Uesaka, I. Stefan, M. Lettmann, Shunji Nishimura, Zs. Dombrádi, C. Louchart, K. Yoshida, T. Miyazaki, F. Flavigny, A. Delbart, Toshiyuki Sumikama, Alan Peyaud, D. Calvet, C. Péron, G. Authelet, T. Isobe, J.-Y. Roussé, J. M. Gheller, V. Werner, Hiroyoshi Sakurai, Daisuke Suzuki, H. Baba, T. Motobayashi, F. Château, E. C. Pollacco, F. Giacoppo, Masafumi Matsushita, Alessandra Corsi, A. Obertelli, Yoshiaki Shiga, L. X. Chung, Dóra Sohler, Shoko Koyama, Z. Korkulu, Satoshi Takeuchi, S. Franchoo, A. Gottardo, Jenny Lee, Yuya Kubota, Hideaki Otsu, K. Matsui, F. Browne, Zs. Vajta, and Satoru Momiyama

Subjects
Physics, Proton, Isotope, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Shell (structure), Nuclear structure, chemistry.chemical_element, 01 natural sciences, 7. Clean energy, Coincidence, Spectral line, Nickel, medicine.anatomical_structure, chemistry, 0103 physical sciences, medicine, Atomic physics, 010306 general physics, Nucleus
Abstract

The nuclear structure of the Ni76 nucleus was investigated by (p,2p) reaction using a NaI(Tl) array to detect the deexciting prompt γ rays. A new transition with an energy of 2227 keV was identified by γγ and γγγ coincidences. According to these coincidence spectra the observed transition connects a new state at 4147 keV and the previously known 41+ state at 1920 keV. Two weaker transitions were also obtained at 2441 and 2838 keV, which could be tentatively placed to feed the known 21+ state at 990 keV. Our shell-model calculations using the Lenzi, Nowacki, Poves, and Sieja interaction produced good candidates for the experimental proton hole states in the observed energy region, and the theoretical cross sections showed good agreement with the experimental values. Although we could not assign all the experimental states to the theoretical ones unambiguously, the results are consistent with a reasonably large Z=28 shell gap for nickel isotopes in accordance with previous studies.

Published
2019

21. 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

22. $^{78}$Ni revealed as a doubly magic stronghold against nuclear deformation

Author

Frédéric Nowacki, L. Olivier, K. Yoneda, Tsuyoshi Miyazaki, H. Wang, I. Stefan, J. Simonis, Zhengyu Xu, C. Santamaria, Javier Fernandez Menendez, Ertan Şahin, D. Calvet, Kazuyuki Ogata, R. Lozeva, C. Louchart, Takaharu Otsuka, Satoshi Takeuchi, Alexandre Obertelli, Yusuke Tsunoda, J.-Y. Roussé, Tadaaki Isobe, F. Giacoppo, F. Château, A. Gottardo, E. C. Pollacco, Jenny Lee, T. Sumikama, K. Matsui, Zs. Vajta, David Steppenbeck, Sophie Péru, S. Nishimura, Zena Patel, Frank Browne, C. M. Shand, Tohru Motobayashi, Shinsuke Ota, S. Momiyama, Hiroyoshi Sakurai, K. Hadynska-Klek, H. Otsu, Alfredo Poves, A. Gillibert, Daisuke Suzuki, Hidetada Baba, A. Delbart, S. Franchoo, Yuki Kubota, V. Lapoux, V. Werner, Pär-Anders Söderström, M. Matsushita, Shunpei Koyama, M. Lettmann, Jason D. Holt, Z. Korkulu, A. Corsi, Alan Peyaud, Achim Schwenk, Yoshiaki Shiga, R. Taniuchi, Jin Wu, L. X. Chung, S. R. Stroberg, M. Niikura, Tomohiro Uesaka, Zs. Dombrádi, Pieter Doornenbal, C. Péron, G. Authelet, J. M. Gheller, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Proton, Nuclear Theory, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, Strong interaction, FOS: Physical sciences, 01 natural sciences, Asymmetry, Nuclear Theory (nucl-th), Magic number (programming), 0103 physical sciences, Effective field theory, Physics::Atomic and Molecular Clusters, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, media_common, Physics, [PHYS]Physics [physics], Multidisciplinary, 010308 nuclear & particles physics, Magic (programming), Atomic nucleus, Atomic physics
Abstract

Nuclear magic numbers, which emerge from the strong nuclear force based on quantum chromodynamics, correspond to fully occupied energy shells of protons, or neutrons inside atomic nuclei. Doubly magic nuclei, with magic numbers for both protons and neutrons, are spherical and extremely rare across the nuclear landscape. While the sequence of magic numbers is well established for stable nuclei, evidence reveals modifications for nuclei with a large proton-to-neutron asymmetry. Here, we provide the first spectroscopic study of the doubly magic nucleus $^{78}$Ni, fourteen neutrons beyond the last stable nickel isotope. We provide direct evidence for its doubly magic nature, which is also predicted by ab initio calculations based on chiral effective field theory interactions and the quasi-particle random-phase approximation. However, our results also provide the first indication of the breakdown of the neutron magic number 50 and proton magic number 28 beyond this stronghold, caused by a competing deformed structure. State-of-the-art phenomenological shell-model calculations reproduce this shape coexistence, predicting further a rapid transition from spherical to deformed ground states with $^{78}$Ni as turning point.

Published
2019

23. Spectroscopic Study in Neutron-Rich Mn Isotopes Around the $N=40$ 'Island of Inversion'

Author

X. D. Tang, C. Péron, G. Authelet, Y. H. Lam, Shunji Nishimura, J. M. Gheller, V. Lapoux, Megumi Niikura, Tomohiro Uesaka, Masaki Sasano, D. Calvet, De-fu Hou, A. Gillibert, K. Matsui, G. L. Stefan, C. M. Shand, F. Browne, H. Baba, Toshiyuki Sumikama, P. M. Walker, M. Lettmann, Feng-Shou Zhang, F. Giacoppo, K. Yoneda, C. Santamaria, Zs. Vajta, David Steppenbeck, L. Olivier, E. C. Pollacco, C. Louchart, Jinguang Wu, Hideaki Otsu, S. M. Lenzi, Yoshiaki Shiga, Bing Ding, M. D. Sun, T. Miyazaki, Satoru Momiyama, A. Obertelli, Shuichi Ota, T. H. Huang, F. Nowacki, Hiroyoshi Sakurai, B. D. Linh, T. Motobayashi, Jenny Lee, P. A. Söderström, H. Lu, R. Lozeva, X.Y. Liu, Zena Patel, K. Hadynska-Klek, E. Sahin, Zhenci Xu, Z. Korkulu, Zs. Dombradi, Yuya Kubota, X. H. Zhou, T. Isobe, P. Doornenbal, Zi Hong Liu, V. Werner, F. Château, Satoshi Takeuchi, W.Q. Zhang, S. Franchoo, H. Wang, Y. H. Zhang, J.-Y. Roussé, L. X. Chung, H. S. Xu, Daisuke Suzuki, Alan Peyaud, A. Corsi, A. Delbart, Ryo Taniuchi, Shoko Koyama, A. Gottardo, Masafumi Matsushita, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, 21.10.-k, Isotope, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Island of inversion, structure evolution, Mineralogy, 23.20.Lv, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], island of inversion, Quansi-rotational band, 7. Clean energy, In-beam γ-ray spectroscopy, 21.60.Cs, Neutron, 21.10.Re
Abstract

International audience; Excited states in Mn isotopes with mass number A from 63 to 67 were studied via in-beam γ–ray spectroscopy following knockout reactions from 67,68Fe. In odd-A isotopes 63,65,67Mn, similar level schemes, consisting of the 11/2-, 9/2-, 7/2-, and 5/2-g.s. level sequence, connected by I →I -1 transitions, were established, the first time for 65,67Mn. Experimental results of odd-A Mn isotopes are compared with large-scale shell-model calculations in the model space that includes the vg9/2 and vd5/2 orbitals with the state-of-the-art LNPS effective interaction. The constructed level schemes in odd-odd isotopes 64,66Mn show rotational-like properties. Spin and parity of the excited states, as well as the πf7/2 ⊗ vg9/2 configuration of the bands are tentatively assigned based on the level systematics in the odd-odd isotopes. These new data extends the knowledge of the excited states in Mn isotopes. Discussion in terms of the systematics helps to deepen our understanding of the N = 40 “island of inversion”.

Published
2018

24. Erratum: Persistence of the Z=28 Shell Gap Around Ni78 : First Spectroscopy of Cu79 [Phys. Rev. Lett. 119 , 192501 (2017)]

Author

Megumi Niikura, Tomohiro Uesaka, K. Yoneda, I. Stefan, Alessandra Corsi, Dóra Sohler, Satoru Momiyama, A. Gillibert, C. Santamaria, Hideaki Otsu, A. Delbart, Kazuyuki Ogata, David Steppenbeck, Ryo Taniuchi, Shoko Koyama, C. M. Shand, Z. Korkulu, A. Gottardo, Jenny Lee, Alan Peyaud, Zsolt Dombrádi, K. Matsui, Yuya Kubota, F. Flavigny, C. Péron, Shunji Nishimura, F. Browne, J.-Y. Roussé, G. Authelet, V. Werner, Yoshiaki Shiga, C. Louchart, Takaharu Otsuka, J. M. Gheller, Toshiyuki Sumikama, Masaki Sasano, E. Sahin, Zhenci Xu, Masafumi Matsushita, Jinguang Wu, P. Doornenbal, Satoshi Takeuchi, S. Franchoo, Shuichi Ota, H. Baba, Yusuke Tsunoda, T. Miyazaki, K. Hadynska-Klek, L. X. Chung, Z Vajta, Daisuke Suzuki, L. Olivier, H. Wang, R. Lozeva, Z. Patel, D. Calvet, T. Isobe, F. Château, F. Giacoppo, V. Lapoux, M. Lettmann, P. A. Söderström, A. Obertelli, Hiroyoshi Sakurai, T. Motobayashi, and E. C. Pollacco

Subjects
Physics, Persistence (psychology), 010308 nuclear & particles physics, 0103 physical sciences, Shell (structure), General Physics and Astronomy, 010306 general physics, Spectroscopy, 01 natural sciences, Molecular physics
Published
2018

25. Erratum: Persistence of the Z=28 Shell Gap Around ^{78}Ni: First Spectroscopy of ^{79}Cu [Phys. Rev. Lett. 119, 192501 (2017)]

Author

L, Olivier, S, Franchoo, M, Niikura, Z, Vajta, D, Sohler, P, Doornenbal, A, Obertelli, Y, Tsunoda, T, Otsuka, G, Authelet, H, Baba, D, Calvet, F, Château, A, Corsi, A, Delbart, J-M, Gheller, A, Gillibert, T, Isobe, V, Lapoux, M, Matsushita, S, Momiyama, T, Motobayashi, H, Otsu, C, Péron, A, Peyaud, E C, Pollacco, J-Y, Roussé, H, Sakurai, C, Santamaria, M, Sasano, Y, Shiga, S, Takeuchi, R, Taniuchi, T, Uesaka, H, Wang, K, Yoneda, F, Browne, L X, Chung, Z, Dombradi, F, Flavigny, F, Giacoppo, A, Gottardo, K, Hadyńska-Klęk, Z, Korkulu, S, Koyama, Y, Kubota, J, Lee, M, Lettmann, C, Louchart, R, Lozeva, K, Matsui, T, Miyazaki, S, Nishimura, K, Ogata, S, Ota, Z, Patel, E, Sahin, C, Shand, P-A, Söderström, I, Stefan, D, Steppenbeck, T, Sumikama, D, Suzuki, V, Werner, J, Wu, and Z, Xu

Abstract

This corrects the article DOI: 10.1103/PhysRevLett.119.192501.

Published
2018

26. 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

27. Inelastic scattering of neutron-rich Ni and Zn isotopes off a proton target

Author

R. Lozeva, M. Lettmann, J.-Y. Roussé, Tadaaki Isobe, Pieter Doornenbal, F. Nowacki, Zena Patel, Satoshi Takeuchi, H. Otsu, K. Matsui, M. L. Cortés, K. Yoneda, C. Santamaria, S. Franchoo, Tohru Motobayashi, Hidetada Baba, E. Sahin, Hiroyoshi Sakurai, Shuichi Ota, C. Péron, S. Nishimura, G. Authelet, F. Giacoppo, Shunpei Koyama, E. C. Pollacco, Alan Peyaud, Jin Wu, L. X. Chung, H. Wang, F. Château, F. Browne, Ryo Taniuchi, J. M. Gheller, Marc Dupuis, T. Sumikama, V. Lapoux, D. Calvet, Zs. Vajta, David Steppenbeck, A. Gillibert, A. Obertelli, Daisuke Suzuki, A. Gottardo, P. A. Söderström, Jenny Lee, S. M. Lenzi, Yoshiaki Shiga, A. Corsi, Kathrin Wimmer, K. Hadynska-Klek, Yuya Kubota, Megumi Niikura, Sophie Péru, Tomohiro Uesaka, I. Stefan, Zs. Dombrádi, C. M. Shand, Norbert Pietralla, A. Delbart, V. Werner, Z. Korkulu, Zhengyu Xu, T. Miyazaki, M. Matsushita, L. Olivier, C. Louchart, Masaki Sasano, Satoru Momiyama, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
Physics, Nuclear and High Energy Physics, Proton, 010308 nuclear & particles physics, Scattering, Hadron, Nuclear Theory, Inelastic scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, 0103 physical sciences, Isotopes of zinc, Gamma spectroscopy, Neutron, 010306 general physics, Nucleon, Nuclear Experiment
Abstract

International audience; Proton inelastic scattering of Ni72,74 and Zn76,80 ions at energies around 235 MeV/nucleon was performed at the Radioactive Isotope Beam Factory and studied using γ-ray spectroscopy. Angular integrated cross sections for direct inelastic scattering to the 21+ and 41+ states were measured. The Jeukenne-Lejeune-Mahaux folding model, extended beyond 200 MeV, was used together with neutron and proton densities stemming from quasiparticle random-phase approximation (QRPA) calculations to interpret the experimental cross sections and to infer neutron to proton matrix element ratios. In addition, coupled-channels calculations with a phenomenological potential were used to determine deformation lengths. For the Ni isotopes, correlations favor neutron excitations, thus conserving the Z=28 gap. A dominance of proton excitation, on the other hand, is observed in the Zn isotopes, pointing to the conservation of the N=50 gap approaching Ni78. These results are in agreement with QRPA and large-scale shell-model calculations.

Published
2018

28. Spectroscopy of2565,67Mn: Strong coupling in the N = 40 'island of inversion'

Author

X.Y. Liu, Z. Liu, B. Ding, P. Doornenbal, A. Obertelli, S.M. Lenzi, P.M. Walker, L.X. Chung, B.D. Linh, G. Authelet, H. Baba, D. Calvet, F. Château, A. Corsi, A. Delbart, J.-M. Gheller, A. Gillibert, T. Isobe, V. Lapoux, M. Matsushita, S. Momiyama, T. Motobayashi, M. Niikura, F. Nowacki, H. Otsu, C. Péron, A. Peyaud, E.C. Pollacco, J.-Y. Roussé, H. Sakurai, M. Sasano, Y. Shiga, S. Takeuchi, R. Taniuchi, T. Uesaka, H. Wang, K. Yoneda, Y.H. Lam, T.H. Huang, M.D. Sun, W.Q. Zhang, H.Y. Lu, D.S. Hou, F. Browne, Zs. Dombradi, S. Franchoo, F. Giacoppo, A. Gottardo, K. Hadynska-Klek, Z. Korkulu, S. Koyama, Y. Kubota, J. Lee, M. Lettmann, R. Lozeva, K. Matsui, T. Miyazaki, S. Nishimura, C. Louchart, L. Olivier, S. Ota, Z. Patel, E. Sahin, C. Santamaria, C. Shand, P.-A. Söderström, G.L. Stefan, D. Steppenbeck, T. Sumikama, D. Suzuki, Zs. Vajta, V. Werner, J. Wu, Z. Xu, X.H. Zhou, Y.H. Zhang, H.S. Xu, and F.S. Zhang

Subjects
In-beam γ-ray spectroscopy, Strong coupling, Nuclear and High Energy Physics, Structure evolution, “Island of inversion” around N=40, lcsh:Physics, lcsh:QC1-999
Abstract

Excited states in 63,65,67Mn were studied via in-beam γ-ray spectroscopy following knockout reactions from 68Fe. Similar level schemes, consisting of the 11/2−, 9/2−, 7/2− and 5/2g.s.− level sequence, connected by I→I−1 transitions, were established, the first time for 65,67Mn. Their level structures show features consistent with strongly-coupled rotational bands with K=5/2. State-of-the-art shell-model calculations with the modified LNPS effective interaction reproduce the observed levels remarkably well and suggest the dominance of 4-particle-4-hole neutron configurations for all the states. The data on the low-lying excited states of odd-mass 53−67Mn provide a textbook example of nuclear structure evolution from weak coupling through decoupling to strong coupling along a single isotopic chain on the n-rich side of the β stability line. These results help to deepen our understanding of the N=40 “island of inversion”. Keywords: In-beam γ-ray spectroscopy, “Island of inversion” around N=40, Strong coupling, Structure evolution

Published
2018

29. Conceptual design of a cryogen-free μMRI device

Author

Marie Poirier-Quinot, Bertrand Baudouy, A. Bonelli, G. Authelet, Jean-Christophe Ginefri, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Unite de recherche en résonance magnétique médicale (URRMM), and Université Paris-Sud - Paris 11 (UP11)

Subjects
Materials science, Conceptual design, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, 0103 physical sciences, Systems engineering, [SDV.IB]Life Sciences [q-bio]/Bioengineering, 02 engineering and technology, 021001 nanoscience & nanotechnology, 0210 nano-technology, 01 natural sciences, ComputingMilieux_MISCELLANEOUS, 010305 fluids & plasmas
Abstract

International audience

Published
2017

30. Persistence of the Z=28 Shell Gap Around Ni78 : First Spectroscopy of Cu79

Author

P. A. Söderström, L. Olivier, I. Stefan, Hiroyoshi Sakurai, Shunji Nishimura, A. Gillibert, Masaki Sasano, Megumi Niikura, T. Motobayashi, Yusuke Tsunoda, T. Miyazaki, C. M. Shand, R. Lozeva, D. Sohler, Tomohiro Uesaka, Yoshiaki Shiga, Takaharu Otsuka, Kazuyuki Ogata, F. Browne, Toshiyuki Sumikama, Ryo Taniuchi, E. Sahin, Zhenci Xu, Zs. Vajta, M. Lettmann, Shuichi Ota, H. Wang, P. Doornenbal, Satoru Momiyama, Satoshi Takeuchi, F. Giacoppo, E. C. Pollacco, L. X. Chung, S. Franchoo, K. Yoneda, Hideaki Otsu, F. Flavigny, Z. Korkulu, David Steppenbeck, A. Obertelli, C. Louchart, K. Hadynska-Klek, A. Gottardo, Jenny Lee, Zsolt Dombrádi, Yuya Kubota, T. Isobe, H. Baba, Jinguang Wu, D. Calvet, V. Lapoux, J.-Y. Roussé, Zena Patel, V. Werner, F. Château, C. Santamaria, Daisuke Suzuki, Masafumi Matsushita, K. Matsui, A. Corsi, A. Delbart, C. Péron, G. Authelet, J. M. Gheller, Alan Peyaud, and Shoko Koyama

Subjects
Physics, Valence (chemistry), 010308 nuclear & particles physics, Nuclear Theory, General Physics and Astronomy, 01 natural sciences, medicine.anatomical_structure, Excited state, 0103 physical sciences, medicine, Physics::Accelerator Physics, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Spectroscopy, Nucleus
Abstract

In-beam γ-ray spectroscopy of Cu79 is performed at the Radioactive Isotope Beam Factory of RIKEN. The nucleus of interest is produced through proton knockout from a Zn80 beam at 270 MeV/nucleon. The level scheme up to 4.6 MeV is established for the first time and the results are compared to Monte Carlo shell-model calculations. We do not observe significant knockout feeding to the excited states below 2.2 MeV, which indicates that the Z=28 gap at N=50 remains large. The results show that the Cu79 nucleus can be described in terms of a valence proton outside a Ni78 core, implying the magic character of the latter.

Published
2017

31. Signatures of triaxiality in low-spin spectra of $^{86}$Ge

Author

I. Stefan, Alessandra Corsi, C. M. Shand, L. Olivier, M. Dewald, Satoru Momiyama, Megumi Niikura, Norbert Pietralla, Tomohiro Uesaka, A. Gillibert, Jian Liu, R. J. Caroll, Bing Ding, Victor Vaquero, A. Gottardo, S. Nagamine, F. Browne, Tomás R. Rodríguez, A. Delbart, D. Calvet, Zs. Podolyák, Ryo Taniuchi, A. Blazhev, C. R. Nobs, T. Arici, T. Saito, C. Lizarazo, G. Authelet, Zena Patel, M. L. Cortés, J.-Y. Roussé, C. R. Nita, Zhenci Xu, J. M. Gheller, David Steppenbeck, A. Jungclaus, M. Lettmann, A. Giganon, A. Obertelli, F. Château, Pieter Doornenbal, Alison Bruce, Kamila Sieja, Toshiaki Ando, M. Górska, Si-Ge Chen, N. Paul, Noritsugu Nakatsuka, M. Rudigier, P. A. Söderström, Zi Hong Liu, V. Werner, C. Santamaria, L. X. Chung, Hiroyoshi Sakurai, T. Motobayashi, K. Moschner, Hidetada Baba, Kathrin Wimmer, B. D. Linh, Jenny Lee, V. Lapoux, S. Franchoo, F. Flavigny, 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 Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-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), Federal Ministry of Education and Research (Germany), SCOAP, European Commission, Ministerio de Economía y Competitividad (España), Vietnam Academy of Science and Technology, Science and Technology Facilities Council (UK), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), 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 Pluridisciplinaire Hubert Curien ( IPHC ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Strasbourg ( UNISTRA ), 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 ), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, History, Time projection chamber, Spectrometer, 010308 nuclear & particles physics, Fission, State (functional analysis), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Spectral line, Computer Science Applications, Education, Nuclear physics, MINOS, 0103 physical sciences, [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, Spectroscopy, Spin (physics)
Abstract

7 pags., 4 figs. -- XXII International School on Nuclear Physics, Neutron Physics and Applications. -- Open Access funded by Creative Commons Atribution Licence 3.0, Low-spin states of neutron-rich Ge-84,Ge-86,Ge-88 were measured by in-flight gamma-ray spectroscopy at 270 MeV/u at the RIKEN-RIBF facility. The exotic beams have been produced by primary U-238 in-flight fission reactions and impinged on the MINOS device. MINOS combines a 10-cm long LH2 target with a Time Projection Chamber (TPC) to reconstruct the reaction vertices. The reactions were selected by the BigRIPS and the ZeroDegree spectrometers for the incoming and outgoing channels, respectively. Emitted gamma radiation was detected by the NaI-array DALI2. De-excitations from the 6(1)(+), 4(1,2)(+), and 2(1,2)(+) states of Ge-84,Ge- 86 and 4(1)(+) and 26 states of Ge-88 were observed. The data are compared to state-of-the-art shell model and beyond-mean-field calculations. Furthermore, a candidate for a 3(1)(+) state of Ge-86 was identified. This state plays a key role in the discussion of ground-state triaxiality of Ge-86, along with other features of the low-energy level scheme., We acknowledge support from the German BMBF Grant Nos. 05P12RDFN1, 05P12RDFN8 and 05P15PKFNA, the ERC Grant No. MINOS258567, the Spanish Ministerio de Economıa y Competitividad under contracts FPA2014-57196-C5-4-P and FIS−2014−53434, the Vietnam Ministry of Science and Technology, as well as from the Science and Technology Facilities Council (STFC). We further thank GSI for providing computing facilities

Published
2017

32. Triaxiality of neutron-rich Ge84,86,88 from low-energy nuclear spectra

Author

L. Olivier, Megumi Niikura, Alison Bruce, Tomohiro Uesaka, I. Stefan, M. Rudigier, Z. Patel, A. Giganon, A. Obertelli, C. R. Nita, Tomás R. Rodríguez, C. M. Shand, Satoru Momiyama, N. Paul, Noritsugu Nakatsuka, S. Nagamine, F. Château, Ryo Taniuchi, Bing Ding, J.-Y. Roussé, Zs. Podolyák, C. R. Nobs, K. Moschner, Zhengyu Xu, T. Arici, Zi Hong Liu, V. Werner, A. Jungclaus, Hiroyoshi Sakurai, Kathrin Wimmer, M. Górska, David Steppenbeck, C. Lizarazo, F. Flavigny, H. Baba, T. Saito, G. Authelet, Kamila Sieja, Toshiaki Ando, M. Dewald, Si-Ge Chen, P. A. Söderström, R. J. Caroll, D. Calvet, Tohru Motobayashi, P. Doornenbal, J. M. Gheller, L. X. Chung, A. Gillibert, Jian Liu, A. Blazhev, Victor Vaquero, Andrea Corsi, M. Lettmann, F. Browne, A. Gottardo, Jenny Lee, M. L. Cortés, S. Franchoo, C. Santamaria, B. D. Linh, V. Lapoux, Norbert Pietralla, and A. Delbart

Subjects
Physics, Low energy, 010308 nuclear & particles physics, Excited state, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Spectroscopy, 01 natural sciences, Spectral line
Abstract

ray transitions between low-spin states of the neutron-rich 84;86;88Ge were measured by means of in-flight -ray spectroscopy at 270 MeV/u. Excited 6+ 1 , 4+ 1;2 and 2+ 1;2 states of 84;86Ge and 4+ 1 and 2+ 1;2 states of 88Ge were observed. Furthermore a candidate for a 3+ 1 state of 86Ge was identified. This state plays a key role in the discussion of ground-state triaxiality of 86Ge, along with other features of its low-energy level scheme. A new region of triaxially deformed nuclei is proposed in the Ge isotopic chain.

Published
2017

33. Shape Evolution in Neutron-Rich Krypton Isotopes Beyond N=60 : First Spectroscopy of Kr98,100

Author

J.-Y. Roussé, Hiroyoshi Sakurai, A. Jungclaus, T. Motobayashi, A. Corsi, Jian Liu, A. Delbart, Victor Vaquero, A. Blazhev, R. Orlandi, C. Lizarazo, J. Libert, G. Authelet, F. Château, Toshiaki Ando, K. Moschner, Zhengyu Xu, N. Paul, Noritsugu Nakatsuka, J. M. Gheller, T. Arici, I. Stefan, C. Santamaria, Zi Hong Liu, V. Werner, T. Saito, Si-Ge Chen, Kathrin Wimmer, Zena Patel, P. A. Söderström, A. Obertelli, S. Nagamine, M. Górska, M. L. Cortés, Alison Bruce, M. Girod, A. Giganon, Raymond J. Carroll, B. Ding, Zs. Podolyák, B. D. Linh, V. Lapoux, Megumi Niikura, Tomohiro Uesaka, L. X. Chung, C. R. Nobs, F. Browne, A. Gottardo, Jenny Lee, P. Doornenbal, A. Gillibert, C. M. Shand, F. Flavigny, H. Baba, C. R. Nita, J.-P. Delaroche, S. Franchoo, Ryo Taniuchi, David Steppenbeck, M. Dewald, L. Olivier, D. Calvet, Tomás R. Rodríguez, Satoru Momiyama, M. Lettmann, and M. Rudigier

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Nuclear Theory, General Physics and Astronomy, Isotopes of krypton, 01 natural sciences, Neutron number, 0103 physical sciences, Isotopes of zirconium, Neutron, Gamma spectroscopy, Atomic physics, Nuclear Experiment, 010306 general physics, Spectroscopy, Nucleon
Abstract

We report on the first γ-ray spectroscopy of low-lying states in neutron-rich 98,100Kr isotopes obtained from 99,101Rb(p,2p) reactions at ∼ 220 MeV/nucleon. A reduction of the 2+ 1 state energies beyond N = 60 demonstrates a significant increase of deformation, shifted in neutron number compared to the sharper transition observed in strontium and zirconium isotopes. State-of-theart beyond-mean-field calculations using the Gogny D1S interaction predict level energies in good agreement with experimental results. The identification of a low-lying (0+ 2 , 2+ 2 ) state in 98Kr provides the first experimental evidence of a competing configuration at low energy in neutron-rich krypton isotopes consistent with the oblate-prolate shape coexistence picture suggested by theory

Published
2017

34. Are There Signatures of Harmonic Oscillator Shells Far from Stability? First Spectroscopy of Zr110

Author

A. Giganon, M. Girod, T. Arici, J.-Y. Roussé, S. Franchoo, Toshiaki Ando, Ryo Taniuchi, A. Jungclaus, B. Ding, Si-Ge Chen, Jian Liu, P. A. Söderström, A. Gillibert, V. Lapoux, Zena Patel, B. D. Linh, Hiroyoshi Sakurai, C. M. Shand, A. Blazhev, C. R. Nita, A. Gottardo, Jenny Lee, T. Motobayashi, J. Libert, B. Bally, F. Château, A. Corsi, A. Delbart, H. Baba, F. Browne, Alison Bruce, Tomoaki Togashi, Megumi Niikura, Zhengyu Xu, J.-P. Delaroche, Tomohiro Uesaka, Tomás R. Rodríguez, P. Doornenbal, M. Rudigier, C. Santamaria, A. Obertelli, T. Saito, Satoru Momiyama, R. Orlandi, M. Lettmann, M. Górska, F. Flavigny, N. Paul, Noritsugu Nakatsuka, M. L. Cortés, Zi Hong Liu, V. Werner, Raymond J. Carroll, V. Vaquero, Paul-Henri Heenen, Zs. Podolyák, I. Stefan, Michaël Bender, C. Lizarazo, L. X. Chung, Yusuke Tsunoda, C. R. Nobs, K. Moschner, G. Authelet, J. M. Gheller, Kathrin Wimmer, David Steppenbeck, Takaharu Otsuka, M. Dewald, D. Calvet, Noritaka Shimizu, L. Olivier, and S. Nagamine

Subjects
Physics, Proton, 010308 nuclear & particles physics, General Physics and Astronomy, 01 natural sciences, 7. Clean energy, 0103 physical sciences, Isotopes of zirconium, Rigid rotor, Atomic physics, 010306 general physics, Nucleon, Ground state, Spectroscopy, Harmonic oscillator, Excitation
Abstract

The first measurement of the low-lying states of the neutron-rich 110 Zr and 112 Mo was performed via in-beam γ -ray spectroscopy after one proton removal on hydrogen at ∼ 200 MeV / nucleon . The 2 + 1 excitation energies were found at 185(11) keV in 110 Zr , and 235(7) keV in 112 Mo , while the R 42 = E ( 4 + 1 ) / E ( 2 + 1 ) ratios are 3.1(2), close to the rigid rotor value, and 2.7(1), respectively. These results are compared to modern energy density functional based configuration mixing models using Gogny and Skyrme effective interactions. We conclude that first levels of 110 Zr exhibit a rotational behavior, in agreement with previous observations of lighter zirconium isotopes as well as with the most advanced Monte Carlo shell model predictions. The data, therefore, do not support a harmonic oscillator shell stabilization scenario at Z = 40 and N = 70 . The present data also invalidate predictions for a tetrahedral ground state symmetry in 110 Zr .

Published
2017

35. Collectivity of neutron-rich Cr and Fe toward N=50

Author

Hidetada Baba, Tohru Motobayashi, Jenny Lee, Yuya Kubota, A. Delbart, Shuichi Ota, R. Lozeva, T. Sumikama, E. Sahin, K. Hadynska-Klek, David Steppenbeck, A. Gottardo, M. Lettmann, C. M. Shand, E. C. Pollacco, S. Nishimura, R. Taniuchi, Alessandra Corsi, Satoshi Takeuchi, Zena Patel, Pieter Doornenbal, V. Lapoux, C. Santamaria, V. Werner, F. Nowacki, S. Franchoo, C. Louchart, Z. Korkulu, Norbert Pietralla, J.-Y. Roussé, Tadaaki Isobe, Zs. Vajta, Daisuke Suzuki, Satoru Momiyama, M. Matsushita, A. Gillibert, Megumi Niikura, Jin Wu, L. X. Chung, P. A. Söderström, Tomohiro Uesaka, Zhengyu Xu, Alan Peyaud, T. Miyazaki, H. Wang, D. Calvet, A. Obertelli, Masaki Sasano, F. Giacoppo, C. Péron, G. Authelet, J. M. Gheller, Hiroyoshi Sakurai, F. Browne, Shoko Koyama, L. Olivier, Zs. Dombradi, F. Château, Hideaki Otsu, I. Stefan, K. Yoneda, K. Matsui, and Yoshiaki Shiga

Subjects
Physics, Nuclear reaction, Isotopes of uranium, 010308 nuclear & particles physics, Island of inversion, Fission, QC1-999, 7. Clean energy, 01 natural sciences, Engineering physics, Uranium-238, Excited state, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Spectrograph
Abstract

Within the SEASTAR project at RIKEN-RIBF, 66 Cr and 70,72 Fe have been produced via protonknockout reactions, and their first excited 2+ and 4+ states have been discovered. The combination of the liquid-hydrogen target and TPC system MINOS has been used in combination with the DALI2 detector array for the first time. A 345 MeV/u 238 U beam with a mean intensity of about 12 pnA impinged on a Be target. Fission fragments were separated and identified using the BigRIPS spectrograph, and reaction products were analyzed using the ZeroDegree spectrograph. A plateau of excitation energies, with a small change in the systematic trends past N = 44, reveals an extension of the N = 40 region of collectivity toward N = 50. Hence, the isotopes of interest are located within the N = 40 island of inversion. An interpretation of the observed trends is offered through large scale shell model calculations.

Published
2016

36. Extension of theN=40Island of Inversion towardsN=50: Spectroscopy ofCr66,Fe70,72

Author

K. Matsui, T. Sumikama, Yoshiaki Shiga, K. Hadynska-Klek, C. Péron, F. Nowacki, G. Authelet, Jin Wu, L. X. Chung, L. Olivier, P. A. Söderström, J. M. Gheller, Tohru Motobayashi, R. Taniuchi, V. Werner, C. Santamaria, F. Château, Pieter Doornenbal, V. Lapoux, Megumi Niikura, Hidetada Baba, Norbert Pietralla, A. Delbart, Tomohiro Uesaka, E. Sahin, I. Stefan, M. Matsushita, R. Lozeva, Hideaki Otsu, Yoshiyuki Kubota, K. Yoneda, Alan Peyaud, D. Calvet, David Steppenbeck, Andrea Corsi, Satoru Momiyama, M. Lettmann, M. Sasano, A. Obertelli, Satoshi Takeuchi, Hiroyoshi Sakurai, S. Franchoo, Zs. Vajta, A. Gottardo, Shoko Koyama, Jenny Lee, F. Browne, E. C. Pollacco, F. Giacoppo, Zsolt Dombrádi, Zeren Korkulu, Zhengyu Xu, C. Louchart, A. Gillibert, C. M. Shand, Daisuke Suzuki, Tsuyoshi Miyazaki, S. Nishimura, Shuichi Ota, H. Wang, J.-Y. Roussé, Tadaaki Isobe, and Zena Patel

Subjects
Physics, Valence (chemistry), Isotope, 010308 nuclear & particles physics, Island of inversion, SHELL model, General Physics and Astronomy, 7. Clean energy, 01 natural sciences, MINOS, Neutron number, 0103 physical sciences, Atomic physics, 010306 general physics, Spectroscopy, Nucleon
Abstract

We report on the measurement of the first 2(+) and 4(+) states of (66)Cr and (70,72)Fe via in-beam γ-ray spectroscopy. The nuclei of interest were produced by (p,2p) reactions at incident energies of 260 MeV/nucleon. The experiment was performed at the Radioactive Isotope Beam Factory, RIKEN, using the DALI 2γ-ray detector array and the novel MINOS device, a thick liquid hydrogen target combined with a vertex tracker. A low-energy plateau of 2(1)(+) and 4(1)(+) energies as a function of the neutron number was observed for N≥38 and N≥40 for even-even Cr and Fe isotopes, respectively. State-of-the-art shell model calculations with a modified Lenzi-Nowacki-Poves-Sieja (LNPS) interaction in the pfg(9/2)d(5/2) valence space reproduce the observations. Interpretation within the shell model shows an extension of the island of inversion at N=40 for more neutron-rich isotopes towards N=50.

Published
2015

37. Inelastic scattering of $^{72,74}Ni$ off a proton target

Author

J.-Y. Roussé, Tadaaki Isobe, David Steppenbeck, R. Lozeva, T. Sumikama, Masaki Sasano, Zs. Dombradi, A. Gillibert, Satoshi Takeuchi, Zhengyu Xu, K. Hadynska-Klek, S. Franchoo, E. C. Pollacco, F. Château, E. Sahin, T. Miyazaki, Satoru Momiyama, Jenny Lee, Zena Patel, C. Santamaria, Hidetada Baba, Daisuke Suzuki, D. Calvet, C. Péron, Z. Korkulu, Yuya Kubota, G. Authelet, Alessandra Corsi, H. Wang, C. M. Shand, J. M. Gheller, M. Matsushita, Pieter Doornenbal, S. Nishimura, M. Lettmann, A. Gottardo, F. Giacoppo, K. Matsui, V. Werner, K. Yoneda, Zs. Vajta, P. A. Söderström, C. Louchart, Shuichi Ota, A. Delbart, R. Taniuchi, M. L. Cortés, Megumi Niikura, Tomohiro Uesaka, F. Browne, Jin Wu, L. X. Chung, L. Olivier, Hideaki Otsu, I. Stefan, Tohru Motobayashi, V. Lapoux, A. Obertelli, Yoshiaki Shiga, Hiroyoshi Sakurai, Shoko Koyama, Norbert Pietralla, Alan Peyaud, 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), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
History, Proton, Spectrometer, Isotope, 010308 nuclear & particles physics, Fission, Gamma ray, chemistry.chemical_element, Inelastic scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Computer Science Applications, Education, Ion, Nuclear physics, chemistry, 0103 physical sciences, Beryllium, Atomic physics, 010306 general physics, Nuclear Experiment
Abstract

International audience; Inelastic scattering of (72,74)Ni off a proton target was performed at RIBF, RIKEN, Japan. The isotopes were produced by the fission of (238)U on a thick Beryllium target and were then selected and identified on an event-by-event basis using the BigRIPS separator. Selected isotopes were focused onto the liquid hydrogen target of the MINOS device and gamma rays from the reactions were measured with the DALI2 array. The energy of the ions in the middle of the target was 213 MeV/u. Outgoing particles were identified using the ZeroDegree spectrometer. Here, we report on the current status of the data analysis and preliminary results for the proton inelastic scattering cross sections for both isotopes.

Published
2015

38. Extension of the N=40 island of inversion towards N=50: Spectroscopy of 66Cr, 70,72Fe

Author

C, Santamaria, C, Louchart, A, Obertelli, V, Werner, P, Doornenbal, F, Nowacki, G, Authelet, H, Baba, D, Calvet, F, Château, A, Corsi, A, Delbart, J-M, Gheller, A, Gillibert, T, Isobe, V, Lapoux, M, Matsushita, S, Momiyama, T, Motobayashi, M, Niikura, H, Otsu, C, Péron, A, Peyaud, E C, Pollacco, J-Y, Roussé, H, Sakurai, M, Sasano, Y, Shiga, S, Takeuchi, R, Taniuchi, T, Uesaka, H, Wang, K, Yoneda, F, Browne, L X, Chung, Zs, Dombradi, S, Franchoo, F, Giacoppo, A, Gottardo, K, Hadynska-Klek, Z, Korkulu, S, Koyama, Y, Kubota, J, Lee, M, Lettmann, R, Lozeva, K, Matsui, T, Miyazaki, S, Nishimura, L, Olivier, S, Ota, Z, Patel, N, Pietralla, E, Sahin, C, Shand, P-A, Söderström, I, Stefan, D, Steppenbeck, T, Sumikama, D, Suzuki, Zs, Vajta, J, Wu, and Z, Xu

Subjects
Természettudományok, Fizikai tudományok
Abstract

We report on the measurement of the first 2(+) and 4(+) states of (66)Cr and (70,72)Fe via in-beam γ-ray spectroscopy. The nuclei of interest were produced by (p,2p) reactions at incident energies of 260 MeV/nucleon. The experiment was performed at the Radioactive Isotope Beam Factory, RIKEN, using the DALI 2γ-ray detector array and the novel MINOS device, a thick liquid hydrogen target combined with a vertex tracker. A low-energy plateau of 2(1)(+) and 4(1)(+) energies as a function of the neutron number was observed for N≥38 and N≥40 for even-even Cr and Fe isotopes, respectively. State-of-the-art shell model calculations with a modified Lenzi-Nowacki-Poves-Sieja (LNPS) interaction in the pfg(9/2)d(5/2) valence space reproduce the observations. Interpretation within the shell model shows an extension of the island of inversion at N=40 for more neutron-rich isotopes towards N=50.

Published
2015

39. Thin-thick hydrogen target for nuclear physics

Author

J. Relland, G. Authelet, J. M. Gheller, I. Vinyar, C. Commeaux, and F.-P. Juster

Subjects
Nuclear physics, Cryostat, Deuterium, Hydrogen, chemistry, Solid hydrogen, Plastics extrusion, Nozzle, chemistry.chemical_element, Vacuum chamber, Cryocooler
Abstract

In spectroscopic studies of unstable nuclei, hydrogen targets are of key importance. The CHyMENE Project aims to provide to the nuclear physics community a thin and pure solid windowless hydrogen or deuterium target. CHyMENE project must respond to this request for the production of solid Hydrogen. The solid hydrogen target is produced in a continuous flow (1 cm/s) by an extrusion technique (developed with the PELIN laboratory) in a vacuum chamber. The shape of the target is determined by the design of the nozzle at the extrusion process. For the purpose, the choice is a rectangular shape with a width of 10 mm and a thickness in the range of 30-50 microns necessary for the physics objectives. The cryostat is equipped with a GM Cryocooler with sufficient power for the solidification of the hydrogen in the lower portion of the extruder. In the higher part of the cryostat, the hydrogen gas is first liquefied and partially solidified. It is then compressed at 100 bars in the cooled extruder before expulsion of the film through the nozzle at the center of the reaction vacuum chamber. After the previous step, the solid hydrogen ribbon falls by gravity into a dedicated chamber where it sublimes and the gas is pumped and evacuated in a exhaust line. This paper deals with the design of the cryostat with its equipment, with the sizing of the thermal bridge (Aluminum and copper), with the results regarding the contact resistance as well as with the vacuum computations of the reaction and recovery hydrogen gas chambers.

Published
2014

40. MINOS: A vertex tracker coupled to a thick liquid-hydrogen target for in-beam spectroscopy of exotic nuclei

Author

Hidetada Baba, C. Péron, G. Authelet, C. Lahonde-Hamdoun, J. M. Gheller, L. Audirac, Tomohiro Uesaka, D. Leboeuf, D. Calvet, Alan Peyaud, A. Mohamed, B. Bruyneel, J.-Y. Roussé, A. Giganon, C. Santamaria, A. Corsi, Alexandre Obertelli, F. Château, D. Loiseau, A. Delbart, E. C. Pollacco, Hideaki Otsu, S. Anvar, P. Doornenbal, J. Ph. Mols, G. Prono, 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, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, RIKEN Nishina Center for Accelerator-Based Science [Wako] (RIKEN RNC), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), and Département d'Electronique, des Détecteurs et d'Informatique pour la Physique (ex SEDI) (DEDIP)

Subjects
Physics, Nuclear and High Energy Physics, Time projection chamber, Luminosity (scattering theory), 010308 nuclear & particles physics, Physics::Instrumentation and Detectors, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Particle detector, Nuclear physics, MINOS, 0103 physical sciences, Nuclear fusion, Gamma spectroscopy, Atomic physics, 010306 general physics, Nucleon, Spectroscopy
Abstract

International audience; MINOS is a new apparatus dedicated to in-beam nuclear structure experiments with lowintensityexotic beams in inverse kinematics at intermediate energies above 150MeV/nucleon. The deviceis composed of a thick liquid-hydrogen target coupled to a compact time projection chamber (TPC) servingas a vertex tracker. Either used for in-beam gamma spectroscopy of bound excited states or invariant-massspectroscopy of unbound states, MINOS aims at improving the luminosity by a very significant factorcompared to standard solid-target material experiments while improving experimental resolutions.

Published
2014

41. Windowless thin solid-hydrogen target: CHyMENE

Author

V. Méot, C. Louchart, A. Lukin, I. Vinyar, A. Corsi, F. Flavigny, A. Gillibert, D. Guillaume, G. Authelet, J. M. Gheller, O. Roig, L. Nalpas, E. C. Pollacco, A. Obertelli, 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, Département des Accélérateurs, de Cryogénie et de Magnétisme (ex SACM) (DACM), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and PELIN Laboratory, 27A, Gzhatskaya, Saint-Petersburg

Subjects
Elastic scattering, Nuclear reaction, Physics, Nuclear and High Energy Physics, Hydrogen, Proton, 010308 nuclear & particles physics, Nuclear Theory, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, 3. Good health, Nuclear physics, chemistry, Solid hydrogen, 0103 physical sciences, Physics::Accelerator Physics, Nuclear fusion, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Beam (structure)
Abstract

International audience; We report on the production of a windowless pure hydrogen H2 film. The thickness is within therange 50–200 μm, in order to be used as a target for nuclear reactions in inverse kinematics with radioactivebeams at low incident energy (2–15MeV/nucleon). We give details about the production conditions and afirst in-beam test in order to measure the thickness and the homogeneity with a 3MeV proton beam.

Published
2013

43. Signatures of triaxiality in low-spin spectra of 86Ge.

Author

M. Lettmann, V. Werner, N. Pietralla, P. Doornenbal, A. Obertelli, T.R. Rodríguez, K. Sieja, G. Authelet, H. Baba, D. Calvet, F. Château, S. Chen, A. Corsi, A. Delbart, J.-M. Gheller, A. Giganon, A. Gillibert, V. Lapoux, T. Motobayashi, and M. Niikura

Published
2018
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45. Inelastic scattering of 72,74Ni off a proton target.

Author

M L Cortés, P Doornenbal, A Obertelli, N Pietralla, V Werner, G Authelet, H Baba, D Calvet, F Château, A Corsi, A Delbart, J-M Gheller, A Gillibert, T Isobe, V Lapoux, C Louchart, M Matsushita, S Momiyama, T Motobayashi, and M Niikura

Published
2016
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46. Mass, Spectroscopy, and Two-Neutron Decay of ^{16}Be.

Author

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

Abstract

The structure and decay of the most neutron-rich beryllium isotope, ^{16}Be, has been investigated following proton knockout from a high-energy ^{17}B beam. Two relatively narrow resonances were observed for the first time, with energies of 0.84(3) and 2.15(5) MeV above the two-neutron decay threshold and widths of 0.32(8) and 0.95(15) MeV, respectively. These were assigned to be the ground (J^{π}=0^{+}) and first excited (2^{+}) state, with E_{x}=1.31(6)  MeV. The mass excess of ^{16}Be was thus deduced to be 56.93(13) MeV, some 0.5 MeV more bound than the only previous measurement. Both states were observed to decay by direct two-neutron emission. Calculations incorporating the evolution of the wave function during the decay as a genuine three-body process reproduced the principal characteristics of the neutron-neutron energy spectra for both levels, indicating that the ground state exhibits a strong spatially compact dineutron component, while the 2^{+} level presents a far more diffuse neutron-neutron distribution.

Published
2024
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47. Quasifree Neutron Knockout Reaction Reveals a Small s-Orbital Component in the Borromean Nucleus ^{17}B.

Author

Yang ZH, Kubota Y, Corsi A, Yoshida K, Sun XX, Li JG, Kimura M, Michel N, Ogata K, Yuan CX, Yuan Q, Authelet G, Baba H, Caesar C, Calvet D, Delbart A, Dozono M, Feng J, Flavigny F, Gheller JM, Gibelin J, Giganon A, Gillibert A, Hasegawa K, Isobe T, Kanaya Y, Kawakami S, Kim D, Kiyokawa Y, Kobayashi M, Kobayashi N, Kobayashi T, Kondo Y, Korkulu Z, Koyama S, Lapoux V, Maeda Y, Marqués FM, Motobayashi T, Miyazaki T, Nakamura T, Nakatsuka N, Nishio Y, Obertelli A, Ohkura A, Orr NA, Ota S, Otsu H, Ozaki T, Panin V, Paschalis S, Pollacco EC, Reichert S, Roussé JY, Saito AT, Sakaguchi S, Sako M, Santamaria C, Sasano M, Sato H, Shikata M, Shimizu Y, Shindo Y, Stuhl L, Sumikama T, Sun YL, Tabata M, Togano Y, Tsubota J, Xu FR, Yasuda J, Yoneda K, Zenihiro J, Zhou SG, Zuo W, and Uesaka T

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
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48. Surface Localization of the Dineutron in ^{11}Li.

Author

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

Abstract

The formation of a dineutron in the ^{11}Li nucleus is found to be localized to the surface region. The experiment measured the intrinsic momentum of the struck neutron in ^{11}Li via the (p,pn) knockout reaction at 246  MeV/nucleon. The correlation angle between the two neutrons is, for the first time, measured as a function of the intrinsic neutron momentum. A comparison with reaction calculations reveals the localization of the dineutron at r∼3.6  fm. The results also support the density dependence of dineutron formation as deduced from Hartree-Fock-Bogoliubov calculations for nuclear matter.

Published
2020
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49. Sequential Nature of (p,3p) Two-Proton Knockout from Neutron-Rich Nuclei.

Author

Frotscher A, Gómez-Ramos M, Obertelli A, Doornenbal P, Authelet G, Baba H, Calvet D, Château F, Chen S, Corsi A, Delbart A, Gheller JM, Giganon A, Gillibert A, Isobe T, Lapoux V, Matsushita M, Momiyama S, Motobayashi T, Niikura M, Otsu H, Paul N, Péron C, Peyaud A, Pollacco EC, Roussé JY, Sakurai H, Santamaria C, Sasano M, Shiga Y, Shimizu N, Steppenbeck D, Takeuchi S, Taniuchi R, Uesaka T, Wang H, Yoneda K, Ando T, Arici T, Blazhev A, Browne F, Bruce AM, Carroll R, Chung LX, Cortés ML, Dewald M, Ding B, Dombradi Z, Flavigny F, Franchoo S, Giacoppo F, Górska M, Gottardo A, Hadyńska-Klęk K, Korkulu Z, Koyama S, Kubota Y, Jungclaus A, Lee J, Lettmann M, Linh BD, Liu J, Liu Z, Lizarazo C, Louchart C, Lozeva R, Matsui K, Miyazaki T, Moschner K, Nagamine S, Nakatsuka N, Nita C, Nishimura S, Nobs CR, Olivier L, Ota S, Patel Z, Podolyák Z, Rudigier M, Sahin E, Saito TY, Shand C, Söderström PA, Stefan IG, Sumikama T, Suzuki D, Orlandi R, Vaquero V, Vajta Z, Werner V, Wimmer K, Wu J, and Xu Z

Abstract

Twenty-one two-proton knockout (p,3p) cross sections were measured from neutron-rich nuclei at ∼250  MeV/nucleon in inverse kinematics. The angular distribution of the three emitted protons was determined for the first time, demonstrating that the (p,3p) kinematics are consistent with two sequential proton-proton collisions within the projectile nucleus. Ratios of (p,3p) over (p,2p) inclusive cross sections follow the trend of other many-nucleon removal reactions, further reinforcing the sequential nature of (p,3p) in neutron-rich nuclei.

Published
2020
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50. Metastable States of ^{92,94}Se: Identification of an Oblate K Isomer of ^{94}Se and the Ground-State Shape Transition between N=58 and 60.

Author

Lizarazo C, Söderström PA, Werner V, Pietralla N, Walker PM, Dong GX, Xu FR, Rodríguez TR, Browne F, Doornenbal P, Nishimura S, Niţă CR, Obertelli A, Ando T, Arici T, Authelet G, Baba H, Blazhev A, Bruce AM, Calvet D, Caroll RJ, Château F, Chen S, Chung LX, Corsi A, Cortés ML, Delbart A, Dewald M, Ding B, Flavigny F, Franchoo S, Gerl J, Gheller JM, Giganon A, Gillibert A, Górska M, Gottardo A, Kojouharov I, Kurz N, Lapoux V, Lee J, Lettmann M, Linh BD, Liu JJ, Liu Z, Momiyama S, Moschner K, Motobayashi T, Nagamine S, Nakatsuka N, Niikura M, Nobs C, Olivier L, Patel Z, Paul N, Podolyák Z, Roussé JY, Rudigier M, Saito TY, Sakurai H, Santamaria C, Schaffner H, Shand C, Stefan I, Steppenbeck D, Taniuchi R, Uesaka T, Vaquero V, Wimmer K, and Xu Z

Abstract

Here we present new information on the shape evolution of the very neutron-rich ^{92,94}Se nuclei from an isomer-decay spectroscopy experiment at the Radioactive Isotope Beam Factory at RIKEN. High-resolution germanium detectors were used to identify delayed γ rays emitted following the decay of their isomers. New transitions are reported extending the previously known level schemes. The isomeric levels are interpreted as originating from high-K quasineutron states with an oblate deformation of β∼0.25, with the high-K state in ^{94}Se being metastable and K hindered. Following this, ^{94}Se is the lowest-mass neutron-rich nucleus known to date with such a substantial K hindrance. Furthermore, it is the first observation of an oblate K isomer in a deformed nucleus. This opens up the possibility for a new region of K isomers at low Z and at oblate deformation, involving the same neutron orbitals as the prolate orbitals within the classic Z∼72 deformed hafnium region. From an interpretation of the level scheme guided by theoretical calculations, an oblate deformation is also suggested for the ^{94}Se_{60} ground-state band.

Published
2020
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