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286 results on '"M. Niikura"'

1. Demonstration of nuclear gamma-ray polarimetry based on a multi-layer CdTe Compton camera

Author

S. Go, Y. Tsuzuki, H. Yoneda, Y. Ichikawa, T. Ikeda, N. Imai, K. Imamura, M. Niikura, D. Nishimura, R. Mizuno, S. Takeda, H. Ueno, S. Watanabe, T. Y. Saito, S. Shimoura, S. Sugawara, A. Takamine, and T. Takahashi

Subjects
Medicine, Science
Abstract

Abstract To detect and track structural changes in atomic nuclei, the systematic study of nuclear levels with firm spin-parity assignments is important. While linear polarization measurements have been applied to determine the electromagnetic character of gamma-ray transitions, the applicable range is strongly limited due to the low efficiency of the detection system. The multi-layer Cadmium-Telluride (CdTe) Compton camera can be a state-of-the-art gamma-ray polarimeter for nuclear spectroscopy with the high position sensitivity and the detection efficiency. We demonstrated the capability to operate this detector as a reliable gamma-ray polarimeter by using polarized 847-keV gamma rays produced by the $$^{56}\textrm{Fe}$$ 56 Fe ( $${ p},{ p'}\gamma $$ p , p ′ γ ) reaction. By combining the experimental data and simulated calculations, the modulation curve for the gamma ray was successfully obtained. A remarkably high polarization sensitivity was achieved, compatible with a reasonable detection efficiency. Based on the obtained results, a possible future gamma-ray polarimetery is discussed.

Published
2024
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2. Isospin symmetry in the T = 1,A = 62 triplet

Author

K. Wimmer, P. Ruotsalainen, S.M. Lenzi, A. Poves, T. Hüyük, F. Browne, P. Doornenbal, T. Koiwai, T. Arici, K. Auranen, M.A. Bentley, M.L. Cortés, C. Delafosse, T. Eronen, Z. Ge, T. Grahn, P.T. Greenlees, A. Illana, N. Imai, H. Joukainen, R. Julin, A. Jungclaus, H. Jutila, A. Kankainen, N. Kitamura, B. Longfellow, J. Louko, R. Lozeva, M. Luoma, B. Mauss, D.R. Napoli, M. Niikura, J. Ojala, J. Pakarinen, X. Pereira-Lopez, P. Rahkila, F. Recchia, M. Sandzelius, J. Sarén, R. Taniuchi, H. Tann, S. Uthayakumaar, J. Uusitalo, V. Vaquero, R. Wadsworth, G. Zimba, and R. Yajzey

Subjects
Physics, QC1-999
Abstract

Excited states in the Tz=0,−1 nuclei 62Ga and 62Ge were populated in direct reactions of relativistic radioactive ion beams at the RIBF. Coincident γ rays were measured with the DALI2+ array and uniquely assigned to the A=62 isobars. In addition, 62Ge was also studied independently at JYFL-ACCLAB using the 24Mg(40Ca,2n)62Ge fusion-evaporation reaction. The first excited T=1,Jπ=2+ states in 62Ga and 62Ge were identified at 979(1) and 965(1) keV, respectively, resolving discrepant interpretations in the literature. States beyond the first 2+ state in 62Ge were also identified for the first time in the present work. The results are compared with shell-model calculations in the fp model space. Mirror and triplet energy differences are analyzed in terms of individual charge-symmetry and charge-independence breaking contributions. The MED results confirm the shrinkage of the p-orbits' radii when they are occupied by at least one nucleon on average.

Published
2023
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3. Covalent functionalization of polypropylene filters with diazirine–photosensitizer conjugates producing visible light driven virus inactivating materials

Author

T. J. Cuthbert, S. Ennis, S. F. Musolino, H. L. Buckley, M. Niikura, J. E. Wulff, and C. Menon

Subjects
Medicine, Science
Abstract

Abstract The SARS-CoV-2 pandemic has highlighted the weaknesses of relying on single-use mask and respirator personal protective equipment (PPE) and the global supply chain that supports this market. There have been no major innovations in filter technology for PPE in the past two decades. Non-woven textiles used for filtering PPE are single-use products in the healthcare environment; use and protection is focused on preventing infection from airborne or aerosolized pathogens such as Influenza A virus or SARS-CoV-2. Recently, C–H bond activation under mild and controllable conditions was reported for crosslinking commodity aliphatic polymers such as polyethylene and polypropylene. Significantly, these are the same types of polymers used in PPE filtration systems. In this report, we take advantage of this C–H insertion method to covalently attach a photosensitizing zinc-porphyrin to the surface of a melt-blow non-woven textile filter material. With the photosensitizer covalently attached to the surface of the textile, illumination with visible light was expected to produce oxidizing 1O2/ROS at the surface of the material that would result in pathogen inactivation. The filter was tested for its ability to inactivate Influenza A virus, an enveloped RNA virus similar to SARS-CoV-2, over a period of four hours with illumination of high intensity visible light. The photosensitizer-functionalized polypropylene filter inactivated our model virus by 99.99% in comparison to a control.

Published
2021
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4. Impact of shell evolution on Gamow-Teller β decay from a high-spin long-lived isomer in 127Ag

Author

H. Watanabe, C.X. Yuan, G. Lorusso, S. Nishimura, Z.Y. Xu, T. Sumikama, P.-A. Söderström, P. Doornenbal, F. Browne, G. Gey, H.S. Jung, J. Taprogge, Zs. Vajta, H.K. Wang, J. Wu, A. Yagi, H. Baba, G. Benzoni, K.Y. Chae, F.C.L. Crespi, N. Fukuda, R. Gernhäuser, N. Inabe, T. Isobe, A. Jungclaus, D. Kameda, G.D. Kim, Y.K. Kim, I. Kojouharov, F.G. Kondev, T. Kubo, N. Kurz, Y.K. Kwon, G.J. Lane, Z. Li, C.-B. Moon, A. Montaner-Pizá, K. Moschner, F. Naqvi, M. Niikura, H. Nishibata, D. Nishimura, A. Odahara, R. Orlandi, Z. Patel, Zs. Podolyák, H. Sakurai, H. Schaffner, G.S. Simpson, K. Steiger, H. Suzuki, H. Takeda, A. Wendt, and K. Yoshinaga

Subjects
Shell evolution, Gamow-Teller β decay, Isomer, 127Ag, Radioactive isotope beam, Physics, QC1-999
Abstract

The change of the shell structure in atomic nuclei, so-called “nuclear shell evolution”, occurs due to changes of major configurations through particle-hole excitations inside one nucleus, as well as due to variation of the number of constituent protons or neutrons. We have investigated how the shell evolution affects Gamow-Teller (GT) transitions that dominate the β decay in the region below 132Sn using the newly obtained experimental data on a long-lived isomer in 127Ag. The T1/2=67.5(9) ms isomer has been identified with a spin and parity of (27/2+) at an excitation energy of 1942−20+14 keV, and found to decay via an internal transition of an E3 character, which competes with the dominant β-decay branches towards the high-spin states in 127Cd. The underlying mechanism of a strong GT transition from the 127Ag isomer is discussed in terms of configuration-dependent optimization of the effective single-particle energies in the framework of a shell-model approach.

Published
2021
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5. Mirror energy differences above the 0f7/2 shell: First γ-ray spectroscopy of the Tz = −2 nucleus 56Zn

Author

A. Fernández, A. Jungclaus, P. Doornenbal, M.A. Bentley, S.M. Lenzi, D. Rudolph, F. Browne, M.L. Cortés, T. Koiwai, R. Taniuchi, V. Vaquero, K. Wimmer, T. Arici, N. Imai, N. Kitamura, B. Longfellow, R. Lozeva, B. Mauss, D.R. Napoli, M. Niikura, X. Pereira-Lopez, S. Pigliapoco, A. Poves, F. Recchia, P. Ruotsalainen, H. Sakurai, S. Uthayakumaar, R. Wadsworth, and R. Yajzey

Subjects
Physics, QC1-999
Abstract

Excited states in 56Zn were populated following one-neutron removal from a 57Zn beam impinging on a Be target at intermediate energies in an experiment conducted at the Radioactive Isotope Beam Factory at RIKEN. Three γ rays were observed and tentatively assigned to the 6+→4+→2+→0+ yrast sequence. This turns 56Zn into the heaviest Tz=−2 nucleus in which excited states are known. The excitation-energy differences between these levels and the isobaric analogue states in the Tz=+2 mirror partner, 56Fe, are compared with large-scale shell-model calculations considering the full pf valence space and various isospin-breaking contributions. This comparison, together with an analysis of the mirror energy differences in the A=58, Tz=±1 pair 58Zn and 58Ni, provides valuable information with respect to the size of the monopole radial and the isovector multipole isospin-breaking terms in the region above doubly-magic 56Ni.

Published
2021
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6. Inclusive cross sections for one- and multi-nucleon removal from Sn, Sb, and Te projectiles beyond the N = 82 shell closure

Author

V. Vaquero, A. Jungclaus, J.L. Rodríguez-Sánchez, J.A. Tostevin, P. Doornenbal, K. Wimmer, S. Chen, E. Nácher, E. Sahin, Y. Shiga, D. Steppenbeck, R. Taniuchi, Z.Y. Xu, T. Ando, H. Baba, F.L. Bello Garrote, S. Franchoo, A. Gargano, K. Hadynska-Klek, A. Kusoglu, J. Liu, T. Lokotko, S. Momiyama, T. Motobayashi, S. Nagamine, N. Nakatsuka, M. Niikura, R. Orlandi, T. Saito, H. Sakurai, P.A. Söderström, G.M. Tveten, Zs. Vajta, and M. Yalcinkaya

Subjects
Physics, QC1-999
Abstract

Inclusive one- and multi-nucleon removal cross sections have been measured for several Sn, Sb and Te isotopes just beyond the N=82 neutron shell closure. The beams were produced in the projectile fission of a 238U beam at the Radioactive Isotope Beam Factory at RIKEN. The experimental cross sections are compared to predictions from the most recent version of the Liege intranuclear cascade model. Although the overall agreement is good, severe discrepancies are observed for the cases of one- and two-neutron removal from 134Sn and 135Sb projectiles and one-proton knockout from all measured N=84 isotones. These discrepancies, as well as the relevance of quasi-elastic reaction channels to the one-neutron removal cross sections, are discussed. In addition, the measured inclusive one-proton knockout cross section for the semi-magic 134Sn projectile is compared to eikonal direct reaction theory calculations to assess if the suppression factors to these calculated cross sections, deduced from data on reactions of lighter projectile nuclei, are also applicable to heavy nuclei. Keywords: Inclusive knockout cross sections, Intranuclear cascade model, Eikonal reaction theory

Published
2019
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7. Discovery of 68Br in secondary reactions of radioactive beams

Author

K. Wimmer, P. Doornenbal, W. Korten, P. Aguilera, A. Algora, T. Ando, T. Arici, H. Baba, B. Blank, A. Boso, S. Chen, A. Corsi, P. Davies, G. de Angelis, G. de France, D.T. Doherty, J. Gerl, R. Gernhäuser, D.G. Jenkins, S. Koyama, T. Motobayashi, S. Nagamine, M. Niikura, A. Obertelli, D. Lubos, B. Rubio, E. Sahin, T.Y. Saito, H. Sakurai, L. Sinclair, D. Steppenbeck, R. Taniuchi, R. Wadsworth, and M. Zielinska

Subjects
Physics, QC1-999
Abstract

The proton-rich isotope 68Br was discovered in secondary fragmentation reactions of fast radioactive beams. Proton-rich secondary beams of 70,71,72Kr and 70Br, produced at the RIKEN Nishina Center and identified by the BigRIPS fragment separator, impinged on a secondary 9Be target. Unambiguous particle identification behind the secondary target was achieved with the ZeroDegree spectrometer. Based on the expected direct production cross sections from neighboring isotopes, the lifetime of the ground or long-lived isomeric state of 68Br was estimated. The results suggest that secondary fragmentation reactions, where relatively few nucleons are removed from the projectile, offer an alternative way to search for new isotopes, as these reactions populate preferentially low-lying states. Keywords: Radioactive beams, New isotope, Direct reaction

Published
2019
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8. First spectroscopy of 61Ti and the transition to the Island of Inversion at N = 40

Author

K. Wimmer, F. Recchia, S.M. Lenzi, S. Riccetto, T. Davinson, A. Estrade, C.J. Griffin, S. Nishimura, F. Nowacki, V. Phong, A. Poves, P.-A. Söderström, O. Aktas, M. Al-Aqeel, T. Ando, H. Baba, S. Bae, S. Choi, P. Doornenbal, J. Ha, L. Harkness-Brennan, T. Isobe, P.R. John, D. Kahl, G. Kiss, I. Kojouharov, N. Kurz, M. Labiche, K. Matsui, S. Momiyama, D.R. Napoli, M. Niikura, C. Nita, Y. Saito, H. Sakurai, H. Schaffner, P. Schrock, C. Stahl, T. Sumikama, V. Werner, W. Witt, and P.J. Woods

Subjects
Physics, QC1-999
Abstract

Isomeric states in 59,61Ti have been populated in the projectile fragmentation of a 345 AMeV 238U beam at the Radioactive Isotope Beam Factory. The decay lifetimes and delayed γ-ray transitions were measured with the EURICA array. Besides the known isomeric state in 59Ti, two isomeric states in 61Ti are observed for the first time. Based on the measured lifetimes, transition multipolarities as well as tentative spins and parities are assigned. Large-scale shell model calculations based on the modified LNPS interaction show that both 59Ti and 61Ti belong to the Island of Inversion at N=40 with ground state configurations dominated by particle-hole excitations to the g9/2 and d5/2 orbits. Keywords: Radioactive beams, Gamma-ray spectroscopy, Isomeric decay, Shell evolution, Island of Inversion

Published
2019
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9. New isomers in 125Pd79 and 127Pd81: Competing proton and neutron excitations in neutron-rich palladium nuclides towards the N = 82 shell closure

Author

H. Watanabe, H.K. Wang, G. Lorusso, S. Nishimura, Z.Y. Xu, T. Sumikama, P.-A. Söderström, P. Doornenbal, F. Browne, G. Gey, H.S. Jung, J. Taprogge, Zs. Vajta, J. Wu, A. Yagi, H. Baba, G. Benzoni, K.Y. Chae, F.C.L. Crespi, N. Fukuda, R. Gernhäuser, N. Inabe, T. Isobe, A. Jungclaus, D. Kameda, G.D. Kim, Y.K. Kim, I. Kojouharov, F.G. Kondev, T. Kubo, N. Kurz, Y.K. Kwon, G.J. Lane, Z. Li, C.-B. Moon, A. Montaner-Pizá, K. Moschner, F. Naqvi, M. Niikura, H. Nishibata, D. Nishimura, A. Odahara, R. Orlandi, Z. Patel, Zs. Podolyák, H. Sakurai, H. Schaffner, G.S. Simpson, K. Steiger, Y. Sun, H. Suzuki, H. Takeda, A. Wendt, and K. Yoshinaga

Subjects
Physics, QC1-999
Abstract

The neutron-rich isotopes of palladium have attracted considerable interest in terms of the evolution of the N=82 neutron shell closure and its influence on the r-process nucleosynthesis. In this Letter, we present the first spectroscopic information on the excited states in 125Pd79 and 127Pd81 studied using the EURICA γ-ray spectrometer, following production via in-flight fission of a high-intensity 238U beam at the RIBF facility. New isomeric states with half-lives of 144(4) ns and 39(6) μs have been assigned spins and parities of (23/2+) and (19/2+) in 125Pd and 127Pd, respectively. The observed level properties are compared to a shell-model calculation, suggesting the competition between proton excitations and neutron excitations in the proton-hole and neutron-hole systems in the vicinity of the doubly magic nucleus 132Sn.

Published
2019
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10. Shape coexistence and isospin symmetry in A = 70 nuclei: Spectroscopy of the Tz = −1 nucleus 70Kr

Author

K. Wimmer, W. Korten, T. Arici, P. Doornenbal, P. Aguilera, A. Algora, T. Ando, H. Baba, B. Blank, A. Boso, S. Chen, A. Corsi, P. Davies, G. de Angelis, G. de France, D.T. Doherty, J. Gerl, R. Gernhäuser, D. Jenkins, S. Koyama, T. Motobayashi, S. Nagamine, M. Niikura, A. Obertelli, D. Lubos, B. Rubio, E. Sahin, T.Y. Saito, H. Sakurai, L. Sinclair, D. Steppenbeck, R. Taniuchi, R. Wadsworth, and M. Zielinska

Subjects
Physics, QC1-999
Abstract

Excited states in the Tz=−1 nucleus 70Kr have been populated using inelastic scattering of a radioactive 70Kr beam as well as one- and two-neutron removal reactions from 71,72Kr at intermediate beam energies. The level scheme of 70Kr was constructed from the observed γ-ray transitions and coincidences. Tentative spin and parity assignments were made based on comparison with the mirror nucleus 70Se. A second 2+ state and a candidate for the corresponding 42+ state suggest shape coexistence in 70Kr. Keywords: Radioactive beams, Gamma-ray spectroscopy, Mirror symmetry, Shape coexistence

Published
2018
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11. 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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12. Is seniority a partial dynamic symmetry in the first νg9/2 shell?

Author

A.I. Morales, G. Benzoni, H. Watanabe, G. de Angelis, S. Nishimura, L. Coraggio, A. Gargano, N. Itaco, T. Otsuka, Y. Tsunoda, P. Van Isacker, F. Browne, R. Daido, P. Doornenbal, Y. Fang, G. Lorusso, Z. Patel, S. Rice, L. Sinclair, P.-A. Söderström, T. Sumikama, J.J. Valiente-Dobón, J. Wu, Z.Y. Xu, A. Yagi, R. Yokoyama, H. Baba, R. Avigo, F.L. Bello Garrote, N. Blasi, A. Bracco, A.M. Bruce, F. Camera, S. Ceruti, F.C.L. Crespi, M.-C. Delattre, Zs. Dombradi, A. Gottardo, T. Isobe, I. Kojouharov, N. Kurz, I. Kuti, S. Lalkovski, K. Matsui, B. Melon, D. Mengoni, T. Miyazaki, V. Modamio-Hoybjor, S. Momiyama, D.R. Napoli, M. Niikura, R. Orlandi, Zs. Podolyák, P.H. Regan, H. Sakurai, E. Sahin, D. Sohler, H. Schaffner, R. Taniuchi, J. Taprogge, Zs. Vajta, O. Wieland, and M. Yalcinkaya

Subjects
Physics, QC1-999
Abstract

The low-lying structures of the midshell νg9/2 Ni isotopes 72Ni and 74Ni have been investigated at the RIBF facility in RIKEN within the EURICA collaboration. Previously unobserved low-lying states were accessed for the first time following β decay of the mother nuclei 72Co and 74Co. As a result, we provide a complete picture in terms of the seniority scheme up to the first (8+) levels for both nuclei. The experimental results are compared to shell-model calculations in order to define to what extent the seniority quantum number is preserved in the first neutron g9/2 shell. We find that the disappearance of the seniority isomerism in the (81+) states can be explained by a lowering of the seniority-four (6+) levels as predicted years ago. For 74Ni, the internal de-excitation pattern of the newly observed (62+) state supports a restoration of the normal seniority ordering up to spin J=4. This property, unexplained by the shell-model calculations, is in agreement with a dominance of the single-particle spherical regime near 78Ni.

Published
2018
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13. 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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14. Observation of a γ-decaying millisecond isomeric state in 128Cd80

Author

A. Jungclaus, H. Grawe, S. Nishimura, P. Doornenbal, G. Lorusso, G.S. Simpson, P.-A. Söderström, T. Sumikama, J. Taprogge, Z.Y. Xu, H. Baba, F. Browne, N. Fukuda, R. Gernhäuser, G. Gey, N. Inabe, T. Isobe, H.S. Jung, D. Kameda, G.D. Kim, Y.-K. Kim, I. Kojouharov, T. Kubo, N. Kurz, Y.K. Kwon, Z. Li, H. Sakurai, H. Schaffner, Y. Shimizu, K. Steiger, H. Suzuki, H. Takeda, Zs. Vajta, H. Watanabe, J. Wu, A. Yagi, K. Yoshinaga, G. Benzoni, S. Bönig, K.Y. Chae, L. Coraggio, J.-M. Daugas, F. Drouet, A. Gadea, A. Gargano, S. Ilieva, N. Itaco, F.G. Kondev, T. Kröll, G.J. Lane, A. Montaner-Pizá, K. Moschner, D. Mücher, F. Naqvi, M. Niikura, H. Nishibata, A. Odahara, R. Orlandi, Z. Patel, Zs. Podolyák, and A. Wendt

Subjects
Isomeric decays, Shell model calculations, Transition strengths, Physics, QC1-999
Abstract

A new high-spin isomer in the neutron-rich nucleus 128Cd was populated in the projectile fission of a 238U beam at the Radioactive Isotope Beam Factory at RIKEN. A half-life of T1/2=6.3(8) ms was measured for the new state which was tentatively assigned a spin/parity of (15−). The experimental results are compared to shell model calculations performed using state-of-the-art realistic effective interactions and to the neighbouring nucleus 129Cd. In the present experiment no evidence was found for the decay of a 18+ E6 spin-trap isomer, based on the complete alignment of the two-neutron and two-proton holes in the 0h11/2 and the 0g9/2 orbit, respectively, which is predicted to exist by the shell model.

Published
2017
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15. Spectroscopic factor and proton formation probability for the d3/2 proton emitter 151mLu

Author

F. Wang, B.H. Sun, Z. Liu, R.D. Page, C. Qi, C. Scholey, S.F. Ashley, L. Bianco, I.J. Cullen, I.G. Darby, S. Eeckhaudt, A.B. Garnsworthy, W. Gelletly, M.B. Gomez-Hornillos, T. Grahn, P.T. Greenlees, D.G. Jenkins, G.A. Jones, P. Jones, D.T. Joss, R. Julin, S. Juutinen, S. Ketelhut, S. Khan, A. Kishada, M. Leino, M. Niikura, M. Nyman, J. Pakarinen, S. Pietri, Z. Podolyak, P. Rahkila, S. Rigby, J. Saren, T. Shizuma, J. Sorri, S. Steer, J. Thomson, N.J. Thompson, J. Uusitalo, P.M. Walker, S. Williams, H.F. Zhang, W.Q. Zhang, and L.H. Zhu

Subjects
Proton emitter, Recoil-decay tagging, Spectroscopic factor, Proton formation probability, WKB approximation, A=151, Physics, QC1-999
Abstract

The quenching of the experimental spectroscopic factor for proton emission from the short-lived d3/2 isomeric state in 151mLu was a long-standing problem. In the present work, proton emission from this isomer has been reinvestigated in an experiment at the Accelerator Laboratory of the University of Jyväskylä. The proton-decay energy and half-life of this isomer were measured to be 1295(5) keV and 15.4(8) μs, respectively, in agreement with another recent study. These new experimental data can resolve the discrepancy in the spectroscopic factor calculated using the spherical WKB approximation. Using the R-matrix approach it is found that the proton formation probability indicates no significant hindrance for the proton decay of 151mLu.

Published
2017
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16. Type II shell evolution in A=70 isobars from the N≥40 island of inversion

Author

A.I. Morales, G. Benzoni, H. Watanabe, Y. Tsunoda, T. Otsuka, S. Nishimura, F. Browne, R. Daido, P. Doornenbal, Y. Fang, G. Lorusso, Z. Patel, S. Rice, L. Sinclair, P.-A. Söderström, T. Sumikama, J. Wu, Z.Y. Xu, A. Yagi, R. Yokoyama, H. Baba, R. Avigo, F.L. Bello Garrote, N. Blasi, A. Bracco, F. Camera, S. Ceruti, F.C.L. Crespi, G. de Angelis, M.-C. Delattre, Zs. Dombradi, A. Gottardo, T. Isobe, I. Kojouharov, N. Kurz, I. Kuti, K. Matsui, B. Melon, D. Mengoni, T. Miyazaki, V. Modamio-Hoybjor, S. Momiyama, D.R. Napoli, M. Niikura, R. Orlandi, H. Sakurai, E. Sahin, D. Sohler, H. Schaffner, R. Taniuchi, J. Taprogge, Zs. Vajta, J.J. Valiente-Dobón, O. Wieland, and M. Yalcinkaya

Subjects
Physics, QC1-999
Abstract

The level structures of 70Co and 70Ni, populated from the β decay of 70Fe, have been investigated using β-delayed γ-ray spectroscopy following in-flight fission of a 238U beam. The experimental results are compared to Monte-Carlo Shell-Model calculations including the pf+g9/2+d5/2 orbitals. The strong population of a (1+) state at 274 keV in 70Co is at variance with the expected excitation energy of ∼1 MeV from near spherical single-particle estimates. This observation indicates a dominance of prolate-deformed intruder configurations in the low-lying levels, which coexist with the normal near spherical states. It is shown that the β decay of the neutron-rich A=70 isobars from the new island of inversion to the Z=28 closed-shell regime progresses in accordance with a newly reported type of shell evolution, the so-called Type II, which involves many particle-hole excitations across energy gaps.

Published
2017
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17. Spallation reaction study for fission products in nuclear waste: Cross section measurements for 137Cs and 90Sr on proton and deuteron

Author

H. Wang, H. Otsu, H. Sakurai, D.S. Ahn, M. Aikawa, P. Doornenbal, N. Fukuda, T. Isobe, S. Kawakami, S. Koyama, T. Kubo, S. Kubono, G. Lorusso, Y. Maeda, A. Makinaga, S. Momiyama, K. Nakano, M. Niikura, Y. Shiga, P.-A. Söderström, H. Suzuki, H. Takeda, S. Takeuchi, R. Taniuchi, Ya. Watanabe, Yu. Watanabe, H. Yamasaki, and K. Yoshida

Subjects
Spallation reaction on proton and deuteron, Transmutation of long-lived fission products, 137Cs, 90Sr, Physics, QC1-999
Abstract

We have studied spallation reactions for the fission products 137Cs and 90Sr for the purpose of nuclear waste transmutation. The spallation cross sections on the proton and deuteron were obtained in inverse kinematics for the first time using secondary beams of 137Cs and 90Sr at 185 MeV/nucleon at the RIKEN Radioactive Isotope Beam Factory. The target dependence has been investigated systematically, and the cross-section differences between the proton and deuteron are found to be larger for lighter spallation products. The experimental data are compared with the PHITS calculation, which includes cascade and evaporation processes. Our results suggest that both proton- and deuteron-induced spallation reactions are promising mechanisms for the transmutation of radioactive fission products.

Published
2016
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18. Evolution of single-particle strength in neutron-rich 71Cu

Author

P. Morfouace, S. Franchoo, K. Sieja, I. Matea, L. Nalpas, M. Niikura, A.M. Sánchez-Benítez, I. Stefan, M. Assié, F. Azaiez, D. Beaumel, S. Boissinot, C. Borcea, R. Borcea, G. Burgunder, L. Cáceres, N. De Séréville, Zs. Dombrádi, J. Elseviers, B. Fernández-Domínguez, A. Gillibert, S. Giron, S. Grévy, F. Hammache, O. Kamalou, V. Lapoux, L. Lefebvre, A. Lepailleur, C. Louchart, G. Marquinez-Duran, I. Martel, A. Matta, D. Mengoni, D.R. Napoli, F. Recchia, J.-A. Scarpaci, D. Sohler, O. Sorlin, M. Stanoiu, C. Stodel, J.-C. Thomas, and Zs. Vajta

Subjects
Physics, QC1-999
Abstract

The strength functions of the πf5/2, πp3/2 and πf7/2 orbitals in neutron-rich 71Cu were obtained in a 72Zn(d,3He)71Cu proton pick-up reaction in inverse kinematics using a radioactive beam of 72Zn at 38 MeV/u. A dedicated set-up was developed to overcome the experimental challenges posed by the low cross section of the reaction and the low energy of the outgoing 3He particles. The excitation-energy spectrum was reconstructed and spectroscopic factors were obtained after analysis of the angular distributions with the finite-range Distorted-Wave Born Approximation (DWBA). The results show that unlike for the πf5/2 orbital and contrary to earlier interpretation, the πf7/2 single-particle strength distribution is not appreciably affected by the addition of neutrons beyond N=40.

Published
2015
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19. Decay properties of 68,69,70Mn: Probing collectivity up to N=44 in Fe isotopic chain

Author

G. Benzoni, A.I. Morales, H. Watanabe, S. Nishimura, L. Coraggio, N. Itaco, A. Gargano, F. Browne, R. Daido, P. Doornenbal, Y. Fang, G. Lorusso, Z. Patel, S. Rice, L. Sinclair, P.-A. Söderström, T. Sumikama, J. Wu, Z.Y. Xu, R. Yokoyama, H. Baba, R. Avigo, F.L. Bello Garrote, N. Blasi, A. Bracco, F. Camera, S. Ceruti, F.C.L. Crespi, G. de Angelis, M.-C. Delattre, Zs. Dombradi, A. Gottardo, T. Isobe, I. Kuti, K. Matsui, B. Melon, D. Mengoni, T. Miyazaki, V. Modamio-Hoybjor, S. Momiyama, D.R. Napoli, M. Niikura, R. Orlandi, H. Sakurai, E. Sahin, D. Sohler, R. Taniuchi, J. Taprogge, Zs. Vajta, J.J. Valiente-Dobón, O. Wieland, and M. Yalcinkaya

Subjects
Physics, QC1-999
Abstract

The β decays Mn68→Fe68, Mn69→Fe69 and Mn70→Fe70 have been measured at the RIBF facility at RIKEN using the EURICA γ spectrometer combined with an active stopper consisting of a stack of Si detectors. The nuclei were produced as fission fragments from a beam of 238U at a bombarding energy of 345 MeV/nucleon impinging on a Be target and selected using the BigRIPS separator. Half-lives and β-delayed neutron emission probabilities have been extracted for these decays, together with first experimental information on excited states populated in 69,70Fe. The data indicate a continuously increasing deformation for Fe isotopes up to A=70. This is interpreted, as for Cr isotopes, in terms of the interplay between the quadrupole correlations of the ν1d5/2 and ν0g9/2 orbitals and the monopole component of the π0f7/2–ν0f5/2 interaction.

Published
2015
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20. Identification of a millisecond isomeric state in Cd81129 via the detection of internal conversion and Compton electrons

Author

J. Taprogge, A. Jungclaus, H. Grawe, S. Nishimura, Z.Y. Xu, P. Doornenbal, G. Lorusso, E. Nácher, G.S. Simpson, P.-A. Söderström, T. Sumikama, H. Baba, F. Browne, N. Fukuda, R. Gernhäuser, G. Gey, N. Inabe, T. Isobe, H.S. Jung, D. Kameda, G.D. Kim, Y.-K. Kim, I. Kojouharov, T. Kubo, N. Kurz, Y.K. Kwon, Z. Li, H. Sakurai, H. Schaffner, K. Steiger, H. Suzuki, H. Takeda, Zs. Vajta, H. Watanabe, J. Wu, A. Yagi, K. Yoshinaga, G. Benzoni, S. Bönig, K.Y. Chae, L. Coraggio, A. Covello, J.-M. Daugas, F. Drouet, A. Gadea, A. Gargano, S. Ilieva, F.G. Kondev, T. Kröll, G.J. Lane, A. Montaner-Pizá, K. Moschner, D. Mücher, F. Naqvi, M. Niikura, H. Nishibata, A. Odahara, R. Orlandi, Z. Patel, Zs. Podolyák, and A. Wendt

Subjects
Physics, QC1-999
Abstract

The decay of an isomeric state in the neutron-rich nucleus 129Cd has been observed via the detection of internal conversion and Compton electrons providing first experimental information on excited states in this nucleus. The isomer was populated in the projectile fission of a 238U beam at the Radioactive Isotope Beam Factory at RIKEN. From the measured yields of γ-rays and internal conversion electrons, a multipolarity of E3 was tentatively assigned to the isomeric transition. A half-life of T1/2=3.6(2) ms was determined for the new state which was assigned a spin of (21/2+), based on a comparison to shell model calculations performed using state-of-the-art realistic effective interactions. Keywords: Isomeric decays, Transition strengths, Shell model calculations

Published
2014
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21. First spectroscopic study of odd-odd Cu78

Author

L. G. Pedersen, E. Sahin, A. Görgen, F. L. Bello Garrote, Y. Tsunoda, T. Otsuka, M. Niikura, S. Nishimura, Z. Xu, H. Baba, G. Benzoni, F. Browne, A. M. Bruce, S. Ceruti, F. C. L. Crespi, R. Daido, G. de Angelis, M.-C. Delattre, Zs. Dombradi, P. Doornenbal, Y. Fang, S. Franchoo, G. Gey, A. Gottardo, T. Isobe, P. R. John, H. S. Jung, I. Kojouharov, T. Kubo, N. Kurz, I. Kuti, Z. Li, G. Lorusso, I. Matea, K. Matsui, D. Mengoni, T. Miyazaki, V. Modamio, S. Momiyama, A. I. Morales, P. Morfouace, D. R. Napoli, F. Naqvi, H. Nishibata, A. Odahara, R. Orlandi, Z. Patel, S. Rice, H. Sakurai, H. Schaffner, L. Sinclair, P.-A. Söderström, D. Sohler, I. G. Stefan, T. Sumikama, D. Suzuki, R. Taniuchi, J. Taprogge, Z. Vajta, J. J. Valiente-Dobón, H. Watanabe, V. Werner, J. Wu, A. Yagi, M. Yalcinkaya, R. Yokoyama, and K. Yoshinaga

Published
2023

22. Gamow-Teller decay of Te142 to I142

Author

B. Moon, C.-B. Moon, A. Odahara, R. Lozeva, S. Nishimura, C. Yuan, F. Browne, P. Doornenbal, G. Lorusso, Z. Patel, S. Rice, L. Sinclair, P.-A. Söderström, T. Sumikama, H. Watanabe, J. Wu, Z. Y. Xu, A. Yagi, D. S. Ahn, H. Baba, F. L. Bello Garrote, R. Daido, J. M. Daugas, F. Didierjean, Y. Fang, N. Fukuda, B. Hong, E. Ideguchi, N. Inabe, T. Ishigaki, T. Isobe, H. S. Jung, D. Kameda, I. Kojouharov, T. Komatsubara, T. Kubo, Y. K. Kwon, C. S. Lee, P. Lee, S. Morimoto, D. Murai, M. Niikura, H. Nishibata, I. Nishizuka, H. Sakurai, Y. Shimizu, H. Suzuki, H. Takeda, K. Tshoo, and R. Yokoyama

Published
2023

23. Structure of Ca36 under the Coulomb Magnifying Glass

Author

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

Subjects
General Physics and Astronomy
Published
2022

24. New narrow resonances observed in the unbound nucleus F15

Author

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

Published
2022

25. Various nuclear structures in Xe140 studied by β decay of ground and isomeric states in I140

Author

A. Yagi, A. Odahara, H. Nishibata, R. Lozeva, C.-B. Moon, S. Nishimura, K. Yoshida, N. Yoshinaga, C. Watanabe, K. Higashiyama, T. Shimoda, R. Daido, Y. Fang, P. S. Lee, B. Moon, P. Doornenbal, G. Lorusso, P.-A. Söderström, T. Sumikama, H. Watanabe, T. Isobe, H. Baba, H. Sakurai, F. Browne, Z. Patel, S. Rice, L. Sinclair, J. Wu, Z. Y. Xu, R. Yokoyama, T. Kubo, N. Inabe, H. Suzuki, N. Fukuda, D. Kameda, H. Takeda, D. S. Ahn, Y. Shimizu, D. Murai, F. L. Bello Garrote, J.-M. Daugas, F. Didierjean, E. Ideguchi, S. Iimura, T. Ishigaki, H. S. Jung, T. Komatsubara, Y. K. Kwon, C. S. Lee, S. Morimoto, M. Niikura, I. Nishizuka, and K. Tshoo

Published
2022

26. Experimental Level Scheme of \(^{78}\)Cu

Author

L.G. Pedersen, E. Sahin, A. Görgen, F.L. Bello Garrote, Y. Tsunoda, T. Otsuka, M. Niikura, S. Nishimura, Z. Xu, H. Baba, G. Benzoni, F. Browne, A.M. Bruce, S. Ceruti, F.C.L. Crespi, R. Daido, G. de Angelis, M.-C. Delattre, Zs. Dombradi, P. Doornenbal, Y. Fang, S. Franchoo, G. Gey, A. Gottardo, T. Isobe, P.R. John, H.S. Jung, I. Kojouharov, T. Kubo, N. Kurz, I. Kuti, Z. Li, G. Lorusso, I. Matea, K. Matsui, D. Mengoni, T. Miyazaki, V. Modamio, S. Momiyama, A.I. Morales, P. Morfouace, D.R. Napoli, F. Naqvi, H. Nishibata, A. Odahara, R. Orlandi, Z. Patel, S. Rice, H. Sakurai, H. Schaffner, L. Sinclair, P.-A. Söderström, D. Sohler, I.G. Stefan, T. Sumikama, D. Suzuki, R. Taniuchi, J. Taprogge, Z. Vajta, J.J. Valiente-Dobón, H. Watanabe, V. Werner, J. Wu, A. Yagi, M. Yalcinkaya, R. Yokoyama, and K. Yoshinaga

Subjects
General Physics and Astronomy
Published
2023

27. First observation of the π0h11/2⊗ν0h9/2 partner orbital configuration in the odd-odd I138 nucleus

Author

B. Moon, A. Gargano, H. Naïdja, C.-B. Moon, A. Odahara, R. Lozeva, S. Nishimura, C. Yuan, F. Browne, P. Doornenbal, G. Lorusso, Z. Patel, S. Rice, M. Si, L. Sinclair, P.-A. Söderström, T. Sumikama, H. Watanabe, J. Wu, Z. Y. Xu, A. Yagi, D. S. Ahn, H. Baba, F. L. Bello Garrote, R. Daido, J. M. Daugas, F. Didierjean, Y. Fang, N. Fukuda, B. Hong, E. Ideguchi, N. Inabe, T. Ishigaki, T. Isobe, H. S. Jung, D. Kameda, I. Kojouharov, T. Komatsubara, T. Kubo, Y. K. Kwon, C. S. Lee, P. Lee, S. Morimoto, D. Murai, M. Niikura, H. Nishibata, I. Nishizuka, H. Sakurai, Y. Shimizu, H. Suzuki, H. Takeda, K. Tshoo, and R. Yokoyama

Published
2022

28. 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

29. Identification of excited states in Te5552107

Author

W. Zhang, B. Cederwall, C. Qi, A. Ertoprak, Ö. Aktas, X. Liu, K. Andgren, K. Auranen, T. Bäck, L. Barber, G. Beeton, D. M. Cullen, I. G. Darby, M. R. Dimmock, S. Eeckhaudt, E. Ganioğlu, M. Górska, T. Grahn, P. T. Greenlees, B. Hadinia, E. Ideguchi, A. Illana, P. M. Jones, D. T. Joss, R. Julin, S. Juutinen, J. M. Keatings, A. Khaplanov, F. Kulali, M. Leino, M. Luoma, B. Lv, B. S. Nara Singh, L. Nelson, M. Niikura, M. Nyman, J. Ojala, R. D. Page, J. Pakarinen, E. S. Paul, C. Petrache, M. Petri, P. Rahkila, P. Ruotsalainen, M. Sandzelius, J. Sarén, C. Scholey, J. F. Smith, J. Sorri, H. Tann, G. Zimba, J. Uusitalo, R. Wadsworth, and R. Wyss

Subjects
010308 nuclear & particles physics, 0103 physical sciences, 010306 general physics, 01 natural sciences
Published
2021

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

Author

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

Abstract

Detailed spectroscopy of the neutron-deficient nucleus ^{36}Ca was obtained up to 9 MeV using the ^{37}Ca(p,d)^{36}Ca and the ^{38}Ca(p,t)^{36}Ca transfer reactions. The radioactive nuclei, produced by the LISE spectrometer at GANIL, interacted with the protons of the liquid hydrogen target CRYPTA, to produce light ejectiles (the deuteron d or triton t) that were detected in the MUST2 detector array, in coincidence with the heavy residues identified by a zero-degree detection system. Our main findings are (i) a similar shift in energy for the 1_{1}^{+} and 2_{1}^{+} states by about -250 keV, as compared with the mirror nucleus ^{36}S; (ii) the discovery of an intruder 0_{2}^{+} state at 2.83(13) MeV, which appears below the first 2^{+} state, in contradiction with the situation in ^{36}S; and (iii) a tentative 0_{3}^{+} state at 4.83(17) MeV, proposed to exhibit a bubble structure with two neutron vacancies in the 2s_{1/2} orbit. The inversion between the 0_{2}^{+} and 2_{1}^{+} states is due to the large mirror energy difference (MED) of -516(130) keV for the former. This feature is reproduced by shell model calculations, using the sd-pf valence space, predicting an almost pure intruder nature for the 0_{2}^{+} state, with two protons (neutrons) being excited across the Z=20 magic closure in ^{36}Ca (^{36}S). This mirror system has the largest MEDs ever observed, if one excludes the few cases induced by the effect of the continuum.

Published
2021

31. β-Decay Half-Lives of 110 Neutron-Rich Nuclei across theN=82Shell Gap: Implications for the Mechanism and Universality of the AstrophysicalrProcess

Author

G. Lorusso, S. Nishimura, Z. Y. Xu, A. Jungclaus, Y. Shimizu, G. S. Simpson, P.-A. Söderström, H. Watanabe, F. Browne, P. Doornenbal, G. Gey, H. S. Jung, B. Meyer, T. Sumikama, J. Taprogge, Zs. Vajta, J. Wu, H. Baba, G. Benzoni, K. Y. Chae, F. C. L. Crespi, N. Fukuda, R. Gernhäuser, N. Inabe, T. Isobe, T. Kajino, D. Kameda, G. D. Kim, Y.-K. Kim, I. Kojouharov, F. G. Kondev, T. Kubo, N. Kurz, Y. K. Kwon, G. J. Lane, Z. Li, A. Montaner-Pizá, K. Moschner, F. Naqvi, M. Niikura, H. Nishibata, A. Odahara, R. Orlandi, Z. Patel, Zs. Podolyák, H. Sakurai, H. Schaffner, P. Schury, S. Shibagaki, K. Steiger, H. Suzuki, H. Takeda, A. Wendt, A. Yagi, and K. Yoshinaga

Published
2015
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32. 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

33. Shape coexistence revealed in the $N=Z$ isotope $^{72}$Kr through inelastic scattering

Author

Pieter Doornenbal, G. de Angelis, M. Niikura, T. Arici, M. Zielinska, D. Lubos, E. Sahin, D. T. Doherty, Hiroyoshi Sakurai, J. Gerl, Victor Vaquero, D. G. Jenkins, S. Nagamine, Tohru Motobayashi, Shunji Nishimura, V. H. Phong, Suet Nee Chen, Toshiaki Ando, W. Korten, Alexandre Obertelli, R. Gernhäuser, J. Libert, Hidetada Baba, Jin Wu, Shunpei Koyama, P. J. Davies, J.-P. Delaroche, A. Boso, D. Steppenbeck, R. Taniuchi, Kathrin Wimmer, R. Wadsworth, Berta Rubio, Tomás R. Rodríguez, A. Corsi, Michel Girod, G. Kiss, P. Aguilera, T. Goigoux, T. Saito, Alejandro Algora, L. Sinclair, B. Blank, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), RIKEN Nishina Center for Accelerator-Based Science, Science and Technology Facilities Council (UK), Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Hungarian Scientific Research Fund, Ministry of Human Capacities (Hungary), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Scattering, Yrast, Hadron, FOS: Physical sciences, State (functional analysis), Inelastic scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Mean field theory, 0103 physical sciences, Nuclear fusion, Nuclear Experiment (nucl-ex), Atomic physics, 010306 general physics, Ground state, Nuclear Experiment
Abstract

12 pags., 11 figs., 2 tabs., The N= Z= 36 nucleus Kr has been studied by inelastic scattering at intermediate energies. Two targets, Be and Au, were used to extract the nuclear deformation length, δ, and the reduced E2 transition probability, B(E2). The previously unknown non-yrast 2 and 4 states as well as a new candidate for the octupole 3 state have been observed in the scattering on the Be target and placed in the level scheme based on γ- γ coincidences. The second 2 state was also observed in the scattering on the Au target and the B(E2;22+→01+) value could be determined for the first time. Analyzing the results in terms of a two-band mixing model shows clear evidence for a oblate-prolate shape coexistence and can be explained by a shape change from an oblate ground state to prolate deformed yrast band from the first 2 state. This interpretation is corroborated by beyond mean field calculations using the Gogny D1S interaction., We would like to thank the RIKEN accelerator and BigRIPS teams for providing the high intensity beams. We thank T. Furumoto for providing us with the optical potentials and A. Moro for giving access to an unpublished version of the FRESCO code. This work has been supported by UK STFC under Grant numbers ST/L005727/1 and ST/P003885/1, the Spanish Ministerio de Economía y Competitividad under Grants FPA2011-24553, FPA2014-52823-C2- 1-P, and PGC2018-094583-B-I00, the Program Severo Ochoa (SEV2014-0398), the European Research Council through the ERC Grant No. MINOS-258567, NKFIH (NN128072), and by the ÚNKP-19-4- DE-65 New National Excellence Program of the Ministry of Human Capacities of Hungary. G. K. acknowledges support from the János Bolyai research fellowship of the Hungarian Academy of Sciences. K. W. acknowledges the support from the Spanish Ministerio de Economía y Competitividad RYC-2017-22007.

Published
2020

34. 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

35. Interplay between nuclear shell evolution and shape deformation revealed by the magnetic moment of $^{75}$Cu

Author

Y. Ichikawa, H. Nishibata, Y. Tsunoda, A. Takamine, K. Imamura, T. Fujita, T. Sato, S. Momiyama, Y. Shimizu, D. S. Ahn, K. Asahi, H. Baba, D. L. Balabanski, F. Boulay, J. M. Daugas, T. Egami, N. Fukuda, C. Funayama, T. Furukawa, G. Georgiev, A. Gladkov, N. Inabe, Y. Ishibashi, T. Kawaguchi, T. Kawamura, Y. Kobayashi, S. Kojima, A. Kusoglu, I. Mukul, M. Niikura, T. Nishizaka, A. Odahara, Y. Ohtomo, T. Otsuka, D. Ralet, G. S. Simpson, T. Sumikama, H. Suzuki, H. Takeda, L. C. Tao, Y. Togano, D. Tominaga, H. Ueno, H. Yamazaki, X. F. Yang, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de 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), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
Physics, Magnetic moment, Nuclear Theory, Shell (structure), General Physics and Astronomy, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Molecular physics, 010305 fluids & plasmas, medicine.anatomical_structure, Nucleosynthesis, 0103 physical sciences, medicine, Nuclear force, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nucleon, Spin (physics), Nuclear Experiment, Nucleus
Abstract

Exotic nuclei are characterized by a number of neutrons (or protons) in excess relative to stable nuclei. Their shell structure, which represents single-particle motion in a nucleus, may vary due to nuclear force and excess neutrons, in a phenomenon called shell evolution. This effect could be counterbalanced by collective modes causing deformations of the nuclear surface. Here, we study the interplay between shell evolution and shape deformation by focusing on the magnetic moment of an isomeric state of the neutron-rich nucleus 75Cu. We measure the magnetic moment using highly spin-controlled rare-isotope beams and achieving large spin alignment via a two-step reaction scheme that incorporates an angular-momentum-selecting nucleon removal. By combining our experiments with numerical simulations of many-fermion correlations, we find that the low-lying states in 75Cu are, to a large extent, of single-particle nature on top of a correlated 74Ni core. We elucidate the crucial role of shell evolution even in the presence of the collective mode, and within the same framework, we consider whether and how the double magicity of the 78Ni nucleus is restored, which is also of keen interest from the perspective of nucleosynthesis in explosive stellar processes., 10 pages, 4 figures

Published
2019

36. $^{78}$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

37. 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

38. 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

39. Identification of a millisecond isomeric state inCd81129via the detection of internal conversion and Compton electrons

Author

Naohiro Inabe, G. D. Kim, N. Fukuda, E. Nacher, M. Niikura, T. Isobe, Pieter Doornenbal, Giuseppe Lorusso, F.G. Kondev, D. Mücher, K. Yoshinaga, Atsuko Odahara, Y.-K. Kim, R. Orlandi, Guillaume Gey, Hiroshi Watanabe, Z. H. Li, D. Kameda, A. Gargano, Jin Wu, K. Moschner, Toshiyuki Sumikama, H. Baba, Zhengyu Xu, H. Schaffner, Hiroyuki Takeda, Jan Taprogge, G. S. Simpson, Toshiyuki Kubo, Ayumi Yagi, A. Covello, S. Ilieva, N. Kurz, A. Wendt, F. Drouet, Hyo Soon Jung, K. Steiger, L. Coraggio, H. Grawe, A. Jungclaus, Roman Gernhäuser, Z Vajta, P. A. Söderström, T. Kröll, A. Gadea, Hiroki Nishibata, I. Kojouharov, S. Nishimura, Frank Browne, G. Benzoni, Younghun Kwon, J.-M. Daugas, Z. Patel, S. Bönig, H. Sakurai, G. J. Lane, Zs. Podolyák, A. Montaner-Pizá, H. Suzuki, F. Naqvi, and K. Y. Chae

Subjects
Physics, Nuclear and High Energy Physics, Millisecond, Fission, Nuclear Theory, Electron, Nuclear isomer, 7. Clean energy, Internal conversion, Excited state, Atomic physics, Nuclear Experiment, Spin (physics), Beam (structure)
Abstract

The decay of an isomeric state in the neutron-rich nucleus 129 Cd has been observed via the detection of internal conversion and Compton electrons providing first experimental information on excited states in this nucleus. The isomer was populated in the projectile fission of a 238 U beam at the Radioactive Isotope Beam Factory at RIKEN. From the measured yields of γ -rays and internal conversion electrons, a multipolarity of E 3 was tentatively assigned to the isomeric transition. A half-life of T 1 / 2 = 3.6 ( 2 ) ms was determined for the new state which was assigned a spin of ( 21 / 2 + ) , based on a comparison to shell model calculations performed using state-of-the-art realistic effective interactions.

Published
2014

40. EFFECT OF DAY SERVICE USAGE FREQUENCY ON THE CONTINUATION DURATION OF HOME LIVING

Author

Y. Kitayama, K. Teranishi, Y. Naruse, M. Niikura, Y. Miyahara, and Y. Shimoda

Subjects
Continuation, Abstracts, Health (social science), Service usage, Duration (project management), Life-span and Life-course Studies, Psychology, Health Professions (miscellaneous), Demography
Abstract

Purpose: The purpose of this study was to clarify the relationship between day service usage frequency and the subsequent continuation duration of home living based on long-term care insurance certification information on elderly people who had received their start care need certification.

Published
2017

41. Shell Evolution towards ^{78}Ni: Low-Lying States in ^{77}Cu

Author

E, Sahin, F L, Bello Garrote, Y, Tsunoda, T, Otsuka, G, de Angelis, A, Görgen, M, Niikura, S, Nishimura, Z Y, Xu, H, Baba, F, Browne, M-C, Delattre, P, Doornenbal, S, Franchoo, G, Gey, K, Hadyńska-Klȩk, T, Isobe, P R, John, H S, Jung, I, Kojouharov, T, Kubo, N, Kurz, Z, Li, G, Lorusso, I, Matea, K, Matsui, D, Mengoni, P, Morfouace, D R, Napoli, F, Naqvi, H, Nishibata, A, Odahara, H, Sakurai, H, Schaffner, P-A, Söderström, D, Sohler, I G, Stefan, T, Sumikama, D, Suzuki, R, Taniuchi, J, Taprogge, Z, Vajta, H, Watanabe, V, Werner, J, Wu, A, Yagi, M, Yalcinkaya, and K, Yoshinaga

Abstract

The level structure of the neutron-rich ^{77}Cu nucleus is investigated through β-delayed γ-ray spectroscopy at the Radioactive Isotope Beam Factory of the RIKEN Nishina Center. Ions of ^{77}Ni are produced by in-flight fission, separated and identified in the BigRIPS fragment separator, and implanted in the WAS3ABi silicon detector array, surrounded by Ge cluster detectors of the EURICA array. A large number of excited states in ^{77}Cu are identified for the first time by correlating γ rays with the β decay of ^{77}Ni, and a level scheme is constructed by utilizing their coincidence relationships. The good agreement between large-scale Monte Carlo shell model calculations and experimental results allows for the evaluation of the single-particle structure near ^{78}Ni and suggests a single-particle nature for both the 5/2_{1}^{-} and 3/2_{1}^{-} states in ^{77}Cu, leading to doubly magic ^{78}Ni.

Published
2017

42. Gamma Decay of Unbound Neutron-Hole States in $^{133}$Sn

Author

V, Vaquero, A, Jungclaus, P, Doornenbal, K, Wimmer, A, Gargano, J A, Tostevin, S, Chen, E, Nácher, E, Sahin, Y, Shiga, D, Steppenbeck, R, Taniuchi, Z Y, Xu, T, Ando, H, Baba, F L Bello, Garrote, S, Franchoo, K, Hadynska-Klek, A, Kusoglu, J, Liu, T, Lokotko, S, Momiyama, T, Motobayashi, S, Nagamine, N, Nakatsuka, M, Niikura, R, Orlandi, T, Saito, H, Sakurai, P A, Söderström, G M, Tveten, Zs, Vajta, M, Yalcinkaya, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and 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
Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

International audience; Excited states in the nucleus Sn133, with one neutron outside the double magic Sn132 core, were populated following one-neutron knockout from a Sn134 beam on a carbon target at relativistic energies at the Radioactive Isotope Beam Factory at RIKEN. Besides the γ rays emitted in the decay of the known neutron single-particle states in Sn133 additional γ strength in the energy range 3.5–5.5 MeV was observed for the first time. Since the neutron-separation energy of Sn133 is low, Sn=2.402(4) MeV, this observation provides direct evidence for the radiative decay of neutron-unbound states in this nucleus. The ability of electromagnetic decay to compete successfully with neutron emission at energies as high as 3 MeV above threshold is attributed to a mismatch between the wave functions of the initial and final states in the latter case. These findings suggest that in the region southeast of Sn132 nuclear structure effects may play a significant role in the neutron versus γ competition in the decay of unbound states. As a consequence, the common neglect of such effects in the evaluation of the neutron-emission probabilities in calculations of global β-decay properties for astrophysical simulations may have to be reconsidered.

Published
2017

43. Production of $N = 126$ Nuclei and Beyond Using Multinucleon Transfer Reactions

Author

Y. X. Watanabe, Y. Hirayama, H. S. Jung, Y. Kakiguchi, H. Miyatake, M. Oyaizu, P. Schury, M. Wada, Y. H. Kim, E. Clement, G. de France, A. Navin, M. Rejmund, C. Schmitt, S. C. Jeong, H. Ishiyama, J. Y. Moon, J. H. Park, N. Imai, S. Kimura, M. Mukai, M. Ahmed, S. H. Choi, J. S. Song, G. Pollarolo, L. Corradi, E. Fioretto, D. Montanari, M. Niikura, D. Suzuki, H. Nishibata, J. Takatsu, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de 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 National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
Nuclear physics, Multinucleon Transfer Reaction, Gas Cell, Chemistry, Deep Inelastic Collision, Production (economics), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, Laser Resonance Ionization
Abstract

International audience; Production of neutron-rich nuclei around N = 126 by multinucleon transfer reactions has recently gained a renewal of interest both theoretically and experimentally. We are now advancing the KISS project at RIKEN to produce those nuclei by multinucleon transfer reactions and measure their lifetimes to investigate the astrophysical environments of the r-process. To investigate the relevance of the production mechanism, we performed measurements for the reaction system 136Xe + 198Pt, using the spectrometer VAMOS++ and the gamma-ray array EXOGAM at GANIL. Cross sections deduced from the measurements for neutron-rich nuclei around N = 126 show a modest enhancement when compared with the GRAZING calculations, indicating the advantage of the multinucleon transfer reactions as compared with fragmentation for production of N = 126 neutron-rich isotones. The possibility for production of neutron-rich nuclei around uranium beyond N = 126 by multinucleon transfer reactions is also discussed.

Published
2016

44. Pathway for the Production of Neutron-Rich Isotopes around the N=126 Shell Closure

Author

Y. X. Watanabe, Y. H. Kim, S. C. Jeong, Y. Hirayama, N. Imai, H. Ishiyama, H. S. Jung, H. Miyatake, S. Choi, J. S. Song, E. Clement, G. de France, A. Navin, M. Rejmund, C. Schmitt, G. Pollarolo, L. Corradi, E. Fioretto, D. Montanari, M. Niikura, D. Suzuki, H. Nishibata, J. Takatsu, KEK (High energy accelerator research organization), Seoul National University [Seoul] (SNU), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Istituto Nazionale di Fisica Nucleare, Sezione di Torino (INFN, Sezione di Torino), Istituto Nazionale di Fisica Nucleare (INFN), Laboratori Nazionali di Legnaro (LNL), Istituto Nazionale di Fisica Nucleare, Sezione di Padova (INFN, Sezione di Padova), 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), Osaka University [Osaka], GANILEXP, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 24.10.-i, 25.70.Hi, 29.30.Aj, Isotope, Spectrometer, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Dissipation, Kinetic energy, 7. Clean energy, Nuclear physics, Neutron, Atomic physics, Nuclear Experiment, Nucleon
Abstract

Expérience GANIL/VAMOS/EXOGAM; International audience; Absolute cross sections for isotopically identified products formed in multinucleon transfer in the136Xe + 198Pt system at ∼ 8 MeV=nucleon are reported. The isotopic distributions obtained using a largeacceptance spectrometer demonstrated the production of the “hard-to-reach” neutron-rich isotopes forZ < 78 around the N = 126 shell closure far from stability. The main contribution to the formation of theseexotic nuclei is shown to arise in collisions with a small kinetic energy dissipation. The presentexperimental finding corroborates for the first time recent predictions that multinucleon transfer reactionswould be the optimum method to populate and characterize neutron-rich isotopes around N = 126 whichare crucial for understanding both astrophysically relevant processes and the evolution of “magic” numbersfar from stability.

Published
2015

45. Low-lying intruder and tensor-driven structures inAs82revealed byβdecay at a new movable-tape-based experimental setup

Author

Alain Goasduff, K. Kolos, S. Roccia, M. Niikura, N. N. Arsenyev, C. Lau, A. Etilé, C. Delafosse, F. Didierjean, F. Ibrahim, Ivan Borzov, D. A. Testov, D. Verney, C. Gaulard, V. V. Voronov, Sandrine Tusseau-Nenez, Phan Viet Cuong, M. Cheikh Mhamed, A. P. Severyukhin, Nguyen Van Giai, and J. Bettane

Subjects
Coupling, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Parity (physics), State (functional analysis), 01 natural sciences, Separable space, Double beta decay, 0103 physical sciences, Quasiparticle, Tensor, Atomic physics, 010306 general physics, Line (formation)
Abstract

The $\ensuremath{\beta}$ decay of $^{82}\mathrm{Ge}$ was re-investigated using the newly commissioned tape station BEDO at the electron-driven ISOL (isotope separation on line) facility ALTO operated by the Institut de Physique Nucl\'eaire, Orsay. The original motivation of this work was focused on the sudden occurrence in the light $N=49$ odd-odd isotonic chain of a large number of $J\ensuremath{\le}1$ states (positive or negative parity) in $^{80}\mathrm{Ga}$ by providing a reliable intermediate example, viz., $^{82}\mathrm{As}$. The extension of the $^{82}\mathrm{As}$ level scheme towards higher energies from the present work has revealed three potential ${1}^{+}$ states above the already known one at 1092 keV. In addition our data allow ruling out the hypothesis that the 843 keV level could be a ${1}^{+}$ state. A detailed analysis of the level scheme using both an empirical core-particle coupling model and a fully microscopic treatment within a Skyrme-QRPA (quasiparticle random-phase approximation) approach using the finite-rank separable approximation was performed. From this analysis two conclusions can be drawn: (i) the presence of a large number of low-lying low-spin negative parity states is due to intruder states stemming from above the $N=50$ shell closure, and (ii) the sudden increase, from $^{82}\mathrm{As}$ to $^{80}\mathrm{Ga}$, of the number of low-lying ${1}^{+}$ states and the corresponding Gamow-Teller fragmentation are naturally reproduced by the inclusion of tensor correlations and couplings to 2p-2h excitations.

Published
2015

46. Evolution of single-particle strength in neutron-rich 71Cu

Author

C. Louchart, G. Marquínez-Durán, P. Morfouace, M. Assié, S. Franchoo, S. Boissinot, D. Beaumel, F. Azaiez, D. Mengoni, J. A. Scarpaci, D. R. Napoli, R. Borcea, Zsolt Dombrádi, Kamila Sieja, L. Lefebvre, A. Matta, Zs. Vajta, F. Recchia, A. Lepailleur, C. Stodel, M. Niikura, Ismael Martel, N. de Séréville, G. Burgunder, B. Fernández-Domínguez, L. Caceres, O. Sorlin, I. Stefan, O. Kamalou, A. M. Sánchez-Benítez, S. Grévy, L. Nalpas, J. Elseviers, A. Gillibert, V. Lapoux, I. Matea, C. Borcea, Fairouz Hammache, M. Stanoiu, Dóra Sohler, J. C. Thomas, S. Giron, 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), 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, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Universidade de Santiago de Compostela [Spain] (USC ), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), GANILEXP, Universidade de Santiago de Compostela. Departamento de Física de Partículas, 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Proton, Fizikai tudományok, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, lcsh:QC1-999, Nuclear physics, Cross section (physics), Distribution (mathematics), Atomic orbital, Természettudományok, Particle, Neutron, Atomic physics, Born approximation, Nuclear Experiment, Radioactive beam, lcsh:Physics
Abstract

The strength functions of the πf5/2πf5/2, πp3/2πp3/2 and πf7/2πf7/2 orbitals in neutron-rich 71Cu were obtained in a 72Zn(d,3He)71Cu proton pick-up reaction in inverse kinematics using a radioactive beam of 72Zn at 38 MeV/u. A dedicated set-up was developed to overcome the experimental challenges posed by the low cross section of the reaction and the low energy of the outgoing 3He particles. The excitation-energy spectrum was reconstructed and spectroscopic factors were obtained after analysis of the angular distributions with the finite-range Distorted-Wave Born Approximation (DWBA). The results show that unlike for the πf5/2πf5/2 orbital and contrary to earlier interpretation, the πf7/2πf7/2 single-particle strength distribution is not appreciably affected by the addition of neutrons beyond N=40N=40., The authors are thankful to the Ganil accelerator staff, informatics service and to the IPN design office. We are grateful for the grant of the Romanian National Authority for Scientific Research, CNCS - UEFISCDI, project number PN-II-ID-PCE-2011-3-048, to the grant FPA2010-22131-C02-01 from the Spanish government and to the OTKA contract No. K100835.

Published
2015

47. 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

48. Revisiting the Level Scheme of the Proton Emitter 151Lu

Author

A. B. Garnsworthy, T. Shizuma, I. J. Cullen, M. Niikura, M. B. Gomez-Hornillos, T. Grahn, D. T. Joss, P. T. Greenlees, B. H. Sun, J. Pakarinen, S. V. Rigby, C. Scholey, D. Seweryniak, S.J. Williams, M. Leino, S. Khan, S. F. Ashley, G. A. Jones, P. Rahkila, S. Pietri, M. Nyman, R. Julin, J. Uusitalo, Zs. Podolyák, D. Jenkins, L. Bianco, S. J. Steer, W. Gelletly, P. Jones, P. M. Walker, D. M. Cullen, J. Sorri, N. J. Thompson, F. Wang, I. G. Darby, S. Juutinen, S. Kettelhut, J. Simpson, R. D. Page, Sarah Eeckhaudt, A. Kishada, Zhongfan Liu, and Jan Sarén

Subjects
Physics, Proton, ta114, level scheme, Atomic physics, proton-tagging technique, proton emitter, Common emitter
Published
2015

49. β-Decay Half-Lives of 110 Neutron-Rich Nuclei across the N=82 Shell Gap: Implications for the Mechanism and Universality of the Astrophysical r Process

Author

G, Lorusso, S, Nishimura, Z Y, Xu, A, Jungclaus, Y, Shimizu, G S, Simpson, P-A, Söderström, H, Watanabe, F, Browne, P, Doornenbal, G, Gey, H S, Jung, B, Meyer, T, Sumikama, J, Taprogge, Zs, Vajta, J, Wu, H, Baba, G, Benzoni, K Y, Chae, F C L, Crespi, N, Fukuda, R, Gernhäuser, N, Inabe, T, Isobe, T, Kajino, D, Kameda, G D, Kim, Y-K, Kim, I, Kojouharov, F G, Kondev, T, Kubo, N, Kurz, Y K, Kwon, G J, Lane, Z, Li, A, Montaner-Pizá, K, Moschner, F, Naqvi, M, Niikura, H, Nishibata, A, Odahara, R, Orlandi, Z, Patel, Zs, Podolyák, H, Sakurai, H, Schaffner, P, Schury, S, Shibagaki, K, Steiger, H, Suzuki, H, Takeda, A, Wendt, A, Yagi, and K, Yoshinaga

Abstract

The β-decay half-lives of 110 neutron-rich isotopes of the elements from _{37}Rb to _{50}Sn were measured at the Radioactive Isotope Beam Factory. The 40 new half-lives follow robust systematics and highlight the persistence of shell effects. The new data have direct implications for r-process calculations and reinforce the notion that the second (A≈130) and the rare-earth-element (A≈160) abundance peaks may result from the freeze-out of an (n,γ)⇄(γ,n) equilibrium. In such an equilibrium, the new half-lives are important factors determining the abundance of rare-earth elements, and allow for a more reliable discussion of the r process universality. It is anticipated that universality may not extend to the elements Sn, Sb, I, and Cs, making the detection of these elements in metal-poor stars of the utmost importance to determine the exact conditions of individual r-process events.

Published
2014

50. Effects of Alloy System on Spontaneous Reverse Transformation Behavior in Steel

Author

M. Niikura, T. Yokota, and K. Sato

Subjects
Austenite, Materials science, Carbon steel, Mechanical Engineering, Metallurgy, Beta ferrite, Alloy, Reverse transformation, engineering.material, Condensed Matter Physics, Mechanics of Materials, Ferrite (iron), engineering, General Materials Science, Adiabatic process, Electrical steel
Published
2003

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