Short-Lived α-Emitting Isotope ^{222}Np and the Stability of the N=126 Magic Shell

L Ma; Z Y Zhang; Z G Gan; X H Zhou; H B Yang; M H Huang; C L Yang; M M Zhang; Y L Tian; Y S Wang; H B Zhou; X T He; Y C Mao; W Hua; L M Duan; W X Huang; Z Liu; X X Xu; Z Z Ren; S G Zhou; H S Xu

doi:10.1103/PhysRevLett.125.032502

Short-Lived α-Emitting Isotope ^{222}Np and the Stability of the N=126 Magic Shell

Phys Rev Lett. 2020 Jul 17;125(3):032502. doi: 10.1103/PhysRevLett.125.032502.

Authors

L Ma¹, Z Y Zhang^{1

2}, Z G Gan^{1

2}, X H Zhou^{1

2}, H B Yang¹, M H Huang¹, C L Yang¹, M M Zhang^{1

2}, Y L Tian¹, Y S Wang^{1

2

3}, H B Zhou⁴, X T He⁵, Y C Mao⁶, W Hua⁷, L M Duan^{1

2}, W X Huang^{1

2}, Z Liu^{1

2}, X X Xu^{1

2}, Z Z Ren⁸, S G Zhou^{9

10

11

12}, H S Xu^{1

2}

Affiliations

¹ CAS Key Laboratory of High Precision Nuclear Spectroscopy, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
² School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China.
³ School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China.
⁴ Guangxi Key Laboratory of Nuclear Physics and Technology, Guangxi Normal University, Guilin 541004, China.
⁵ College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
⁶ Department of Physics, Liaoning Normal University, Dalian 116029, China.
⁷ Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-Sen University, Zhuhai 519082, China.
⁸ School of Physics Science and Engineering, Tongji University, Shanghai 200092, China.
⁹ CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China.
¹⁰ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
¹¹ Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, China.
¹² Synergetic Innovation Center for Quantum Effects and Application, Hunan Normal University, Changsha 410081, China.

PMID: 32745401
DOI: 10.1103/PhysRevLett.125.032502

Abstract

A new, very short-lived neutron-deficient isotope ^{222}Np was produced in the complete-fusion reaction ^{187}Re(^{40}Ar,5n)^{222}Np, and observed at the gas-filled recoil separator SHANS. The new isotope ^{222}Np was identified by employing a recoil-α correlation measurement, and six α-decay chains were established for it. The decay properties of ^{222}Np with E_{α}=10016(33) keV and T_{1/2}=380_{-110}^{+260} ns were determined experimentally. The α-decay systematics of Np isotopes is improved by adding the new data for ^{222}Np, which validates the N=126 shell effect in Np isotopes. The evolution of the N=126 shell closure is discussed in the neutron-deficient nuclei up to Np within the framework of α-decay reduced width.