Magic Nature of Neutrons in Ca 54: First Mass Measurements of Ca 55-57

S. Michimasa; M. Kobayashi; Y. Kiyokawa; S. Ota; D. S. Ahn; H. Baba; G. P.A. Berg; M. Dozono; N. Fukuda; T. Furuno; E. Ideguchi; N. Inabe; T. Kawabata; S. Kawase; K. Kisamori; K. Kobayashi; T. Kubo; Y. Kubota; C. S. Lee; M. Matsushita; H. Miya; A. Mizukami; H. Nagakura; D. Nishimura; H. Oikawa; H. Sakai; Y. Shimizu; A. Stolz; H. Suzuki; M. Takaki; H. Takeda; S. Takeuchi; H. Tokieda; T. Uesaka; K. Yako; Y. Yamaguchi; Y. Yanagisawa; R. Yokoyama; K. Yoshida; S. Shimoura

doi:10.1103/PhysRevLett.121.022506

Magic Nature of Neutrons in Ca 54: First Mass Measurements of Ca 55-57

S. Michimasa, M. Kobayashi, Y. Kiyokawa, S. Ota, D. S. Ahn, H. Baba, G. P.A. Berg, M. Dozono, N. Fukuda, T. Furuno, E. Ideguchi, N. Inabe, T. Kawabata, S. Kawase, K. Kisamori, K. Kobayashi, T. Kubo, Y. Kubota, C. S. Lee, M. MatsushitaH. Miya, A. Mizukami, H. Nagakura, D. Nishimura, H. Oikawa, H. Sakai, Y. Shimizu, A. Stolz, H. Suzuki, M. Takaki, H. Takeda, S. Takeuchi, H. Tokieda, T. Uesaka, K. Yako, Y. Yamaguchi, Y. Yanagisawa, R. Yokoyama, K. Yoshida, S. Shimoura

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Abstract

We perform the first direct mass measurements of neutron-rich calcium isotopes beyond neutron number 34 at the RIKEN Radioactive Isotope Beam Factory by using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of Ca55-57 are determined for the first time to be -18650(160), -13510(250), and -7370(990) keV, respectively. We examine the emergence of neutron magicity at N=34 based on the new atomic masses. The new masses provide experimental evidence for the appearance of a sizable energy gap between the neutron 2p1/2 and 1f5/2 orbitals in Ca54, comparable to the gap between the neutron 2p3/2 and 2p1/2 orbitals in Ca52. For the Ca56 nucleus, an open-shell property in neutrons is suggested.

Original language	English
Article number	022506
Journal	Physical review letters
Volume	121
Issue number	2
DOIs	https://doi.org/10.1103/PhysRevLett.121.022506
Publication status	Published - Jul 11 2018

All Science Journal Classification (ASJC) codes

Physics and Astronomy(all)

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10.1103/PhysRevLett.121.022506

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Michimasa, S., Kobayashi, M., Kiyokawa, Y., Ota, S., Ahn, D. S., Baba, H., Berg, G. P. A., Dozono, M., Fukuda, N., Furuno, T., Ideguchi, E., Inabe, N., Kawabata, T., Kawase, S., Kisamori, K., Kobayashi, K., Kubo, T., Kubota, Y., Lee, C. S., ... Shimoura, S. (2018). Magic Nature of Neutrons in Ca 54: First Mass Measurements of Ca 55-57. Physical review letters, 121(2), [022506]. https://doi.org/10.1103/PhysRevLett.121.022506

Michimasa, S, Kobayashi, M, Kiyokawa, Y, Ota, S, Ahn, DS, Baba, H, Berg, GPA, Dozono, M, Fukuda, N, Furuno, T, Ideguchi, E, Inabe, N, Kawabata, T, Kawase, S, Kisamori, K, Kobayashi, K, Kubo, T, Kubota, Y, Lee, CS, Matsushita, M, Miya, H, Mizukami, A, Nagakura, H, Nishimura, D, Oikawa, H, Sakai, H, Shimizu, Y, Stolz, A, Suzuki, H, Takaki, M, Takeda, H, Takeuchi, S, Tokieda, H, Uesaka, T, Yako, K, Yamaguchi, Y, Yanagisawa, Y, Yokoyama, R, Yoshida, K & Shimoura, S 2018, 'Magic Nature of Neutrons in Ca 54: First Mass Measurements of Ca 55-57', Physical review letters, vol. 121, no. 2, 022506. https://doi.org/10.1103/PhysRevLett.121.022506

@article{860ba0b0791b4e22b74b501458655865,

title = "Magic Nature of Neutrons in Ca 54: First Mass Measurements of Ca 55-57",

abstract = "We perform the first direct mass measurements of neutron-rich calcium isotopes beyond neutron number 34 at the RIKEN Radioactive Isotope Beam Factory by using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of Ca55-57 are determined for the first time to be -18650(160), -13510(250), and -7370(990) keV, respectively. We examine the emergence of neutron magicity at N=34 based on the new atomic masses. The new masses provide experimental evidence for the appearance of a sizable energy gap between the neutron 2p1/2 and 1f5/2 orbitals in Ca54, comparable to the gap between the neutron 2p3/2 and 2p1/2 orbitals in Ca52. For the Ca56 nucleus, an open-shell property in neutrons is suggested.",

author = "S. Michimasa and M. Kobayashi and Y. Kiyokawa and S. Ota and Ahn, {D. S.} and H. Baba and Berg, {G. P.A.} and M. Dozono and N. Fukuda and T. Furuno and E. Ideguchi and N. Inabe and T. Kawabata and S. Kawase and K. Kisamori and K. Kobayashi and T. Kubo and Y. Kubota and Lee, {C. S.} and M. Matsushita and H. Miya and A. Mizukami and H. Nagakura and D. Nishimura and H. Oikawa and H. Sakai and Y. Shimizu and A. Stolz and H. Suzuki and M. Takaki and H. Takeda and S. Takeuchi and H. Tokieda and T. Uesaka and K. Yako and Y. Yamaguchi and Y. Yanagisawa and R. Yokoyama and K. Yoshida and S. Shimoura",

note = "Funding Information: We thank the RIKEN Nishina Center and the Center for Nuclear Study, the University of Tokyo accelerator staff for the excellent beam delivery. We also thank Professor N. Shimizu for the fruitful discussions. This work is financially supported in part by JSPS KAKENHI Grant No. JP22740150. M. K. is grateful to the JSPS for a Research Fellowship for young scientists under Program No. JP14J03376. G. P. A. B. acknowledges support from the National Science Foundation through Grant No. PHY-1068192, and the Joint Institute for Nuclear Astrophysics Center for the Evolution of the Elements through Grants No. PHY-0822648 and No. PHY-1430152. Funding Information: This work is financially supported in part by JSPS KAKENHI Grant No. JP22740150. M.K. is grateful to the JSPS for a Research Fellowship for young scientists under Program No. JP14J03376. G.P.A.B. acknowledges support from the National Science Foundation through Grant No. PHY-1068192, and the Joint Institute for Nuclear Astrophysics Center for the Evolution of the Elements through Grants No. PHY-0822648 and No. PHY-1430152. Publisher Copyright: {\textcopyright} 2018 American Physical Society.",

year = "2018",

month = jul,

day = "11",

doi = "10.1103/PhysRevLett.121.022506",

language = "English",

volume = "121",

journal = "Physical Review Letters",

issn = "0031-9007",

publisher = "American Physical Society",

number = "2",

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TY - JOUR

T1 - Magic Nature of Neutrons in Ca 54

T2 - First Mass Measurements of Ca 55-57

AU - Michimasa, S.

AU - Kobayashi, M.

AU - Kiyokawa, Y.

AU - Ota, S.

AU - Ahn, D. S.

AU - Baba, H.

AU - Berg, G. P.A.

AU - Dozono, M.

AU - Fukuda, N.

AU - Furuno, T.

AU - Ideguchi, E.

AU - Inabe, N.

AU - Kawabata, T.

AU - Kawase, S.

AU - Kisamori, K.

AU - Kobayashi, K.

AU - Kubo, T.

AU - Kubota, Y.

AU - Lee, C. S.

AU - Matsushita, M.

AU - Miya, H.

AU - Mizukami, A.

AU - Nagakura, H.

AU - Nishimura, D.

AU - Oikawa, H.

AU - Sakai, H.

AU - Shimizu, Y.

AU - Stolz, A.

AU - Suzuki, H.

AU - Takaki, M.

AU - Takeda, H.

AU - Takeuchi, S.

AU - Tokieda, H.

AU - Uesaka, T.

AU - Yako, K.

AU - Yamaguchi, Y.

AU - Yanagisawa, Y.

AU - Yokoyama, R.

AU - Yoshida, K.

AU - Shimoura, S.

N1 - Funding Information: We thank the RIKEN Nishina Center and the Center for Nuclear Study, the University of Tokyo accelerator staff for the excellent beam delivery. We also thank Professor N. Shimizu for the fruitful discussions. This work is financially supported in part by JSPS KAKENHI Grant No. JP22740150. M. K. is grateful to the JSPS for a Research Fellowship for young scientists under Program No. JP14J03376. G. P. A. B. acknowledges support from the National Science Foundation through Grant No. PHY-1068192, and the Joint Institute for Nuclear Astrophysics Center for the Evolution of the Elements through Grants No. PHY-0822648 and No. PHY-1430152. Funding Information: This work is financially supported in part by JSPS KAKENHI Grant No. JP22740150. M.K. is grateful to the JSPS for a Research Fellowship for young scientists under Program No. JP14J03376. G.P.A.B. acknowledges support from the National Science Foundation through Grant No. PHY-1068192, and the Joint Institute for Nuclear Astrophysics Center for the Evolution of the Elements through Grants No. PHY-0822648 and No. PHY-1430152. Publisher Copyright: © 2018 American Physical Society.

PY - 2018/7/11

Y1 - 2018/7/11

N2 - We perform the first direct mass measurements of neutron-rich calcium isotopes beyond neutron number 34 at the RIKEN Radioactive Isotope Beam Factory by using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of Ca55-57 are determined for the first time to be -18650(160), -13510(250), and -7370(990) keV, respectively. We examine the emergence of neutron magicity at N=34 based on the new atomic masses. The new masses provide experimental evidence for the appearance of a sizable energy gap between the neutron 2p1/2 and 1f5/2 orbitals in Ca54, comparable to the gap between the neutron 2p3/2 and 2p1/2 orbitals in Ca52. For the Ca56 nucleus, an open-shell property in neutrons is suggested.

AB - We perform the first direct mass measurements of neutron-rich calcium isotopes beyond neutron number 34 at the RIKEN Radioactive Isotope Beam Factory by using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of Ca55-57 are determined for the first time to be -18650(160), -13510(250), and -7370(990) keV, respectively. We examine the emergence of neutron magicity at N=34 based on the new atomic masses. The new masses provide experimental evidence for the appearance of a sizable energy gap between the neutron 2p1/2 and 1f5/2 orbitals in Ca54, comparable to the gap between the neutron 2p3/2 and 2p1/2 orbitals in Ca52. For the Ca56 nucleus, an open-shell property in neutrons is suggested.

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U2 - 10.1103/PhysRevLett.121.022506

DO - 10.1103/PhysRevLett.121.022506

M3 - Article

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AN - SCOPUS:85049984192

SN - 0031-9007

VL - 121

JO - Physical Review Letters

JF - Physical Review Letters

IS - 2

M1 - 022506

ER -

Magic Nature of Neutrons in Ca 54: First Mass Measurements of Ca 55-57

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