| Literature DB >> 30085708 |
S Michimasa1, M Kobayashi1, Y Kiyokawa1, S Ota1, D S Ahn2, H Baba2, G P A Berg3, M Dozono1, N Fukuda2, T Furuno4, E Ideguchi5, N Inabe2, T Kawabata4, S Kawase6, K Kisamori1, K Kobayashi7, T Kubo8,9, Y Kubota2, C S Lee1,2, M Matsushita1, H Miya1, A Mizukami10, H Nagakura7, D Nishimura11, H Oikawa10, H Sakai2, Y Shimizu2, A Stolz9, H Suzuki2, M Takaki1, H Takeda2, S Takeuchi12, H Tokieda1, T Uesaka2, K Yako1, Y Yamaguchi1, Y Yanagisawa2, R Yokoyama13, K Yoshida2, S Shimoura1.
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 ^{55-57}Ca 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 2p_{1/2} and 1f_{5/2} orbitals in ^{54}Ca, comparable to the gap between the neutron 2p_{3/2} and 2p_{1/2} orbitals in ^{52}Ca. For the ^{56}Ca nucleus, an open-shell property in neutrons is suggested.Entities:
Year: 2018 PMID： 30085708 DOI： 10.1103/PhysRevLett.121.022506
Source DB: PubMed Journal: Phys Rev Lett ISSN： 0031-9007 Impact factor: 9.161