新同位素\(^{160}Os\)和\(^{156}W\)的发现：揭示缺中子一侧\(N = 82\)壳层闭壳的增强稳定性

Discovery of New Isotopes ^{160}Os and ^{156}W: Revealing Enhanced Stability of the N=82 Shell Closure on the Neutron-Deficient Side.

作者信息

Yang H B, Gan Z G, Li Y J, Liu M L, Xu S Y, Liu C, Zhang M M, Zhang Z Y, Huang M H, Yuan C X, Wang S Y, Ma L, Wang J G, Han X C, Rohilla A, Zuo S Q, Xiao X, Zhang X B, Zhu L, Yue Z F, Tian Y L, Wang Y S, Yang C L, Zhao Z, Huang X Y, Li Z C, Sun L C, Wang J Y, Yang H R, Lu Z W, Yang W Q, Zhou X H, Huang W X, Wang N, Zhou S G, Ren Z Z, Xu H S

机构信息

Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China.

School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China.

出版信息

Phys Rev Lett. 2024 Feb 16;132(7):072502. doi: 10.1103/PhysRevLett.132.072502.

DOI:10.1103/PhysRevLett.132.072502

PMID:38427897

Abstract

Using the fusion-evaporation reaction ^{106}Cd(^{58}Ni,4n)^{160}Os and the gas-filled recoil separator SHANS, two new isotopes {76}^{160}Os and {74}^{156}W have been identified. The α decay of ^{160}Os, measured with an α-particle energy of 7080(26) keV and a half-life of 201{-37}^{+58} μs, is assigned to originate from the ground state. The daughter nucleus ^{156}W is a β^{+} emitter with a half-life of 291{-61}^{+86} ms. The newly measured α-decay data allow us to derive α-decay reduced widths (δ^{2}) for the N=84 isotones up to osmium (Z=76), which are found to decrease with increasing atomic number above Z=68. The reduction of δ^{2} is interpreted as evidence for the strengthening of the N=82 shell closure toward the proton drip line, supported by the increase of the neutron-shell gaps predicted in theoretical models.

摘要

利用熔合蒸发反应(^{106}Cd(^{58}Ni,4n)^{160}Os)和充气反冲分离器SHANS，已鉴定出两种新同位素({76}^{160}Os)和({74}^{156}W)。用(7080(26)\ keV)的α粒子能量和(201_{-37}^{+58}\ \mu s)的半衰期测量的(^{160}Os)的α衰变被认为起源于基态。子核(^{156}W)是一个β⁺发射体，半衰期为(291_{-61}^{+86}\ ms)。新测量的α衰变数据使我们能够推导出直到锇（(Z = 76)）的(N = 84)同中子素的α衰变约化宽度（(\delta^{2})），发现其在(Z = 68)以上随着原子序数的增加而减小。(\delta^{2})的减小被解释为(N = 82)壳层在朝向质子滴线方向加强封闭的证据，这得到了理论模型中预测的中子壳层间隙增加的支持。