Nuclear structure of proton-rich unstable nucleus ~(28)P studied by g-factor measurement

Nuclear structure of proton-rich unstable nucleus 28P has been studied by measuring its g-factor for the first time. The g-factor of 28P (Iπ =3+, T1/2=270.3 ms) was measured by means of β-NMR technique combined with the new polarization technique for charge exchange reaction product in the intermediate energy heavy ion collisions. The obtained g-factor of g=0.1028(27) is very much quenched from the Schmidt value, but is well reproduced by the shell model (+0.102). In connection with the magnetic moment of t...     

Nuclear Structure and Magnetic Moment of the Unstable 12B-12N Mirror Pair

Magnetic moments of the A=12 unstable mirror pair nuclides 12B and 12N have been measured by the β-NMR technique. The experimentally measured magnetic moments are μ（12B）=1.001（17）μN and μ（12N）=0.4571（1）μN. The improved shell model using an SFO Hamiltonian with enhanced spin-isospin monopole proton-neutron interaction and modified single-particle energies is employed to calculate the magnetic moments of 12B and 12N. The calculation yields μ （12B）=0.929μN and μ（12N）=0.452μN and has produced a new magic number 6 for the short-lived unstable mirror pair nuclides 12B and 12N.     

The g-factors and magnetic rotation in 82Rb

The g-factors of the intra-band states 12,13,14,15 in a magnetic-rotational band built on the 11 state in 82 Rb are measured for the first time by using a transient magnetic field-ion implantation perturbed angular distribution (TMF-IMPAD) method.The magnetic-rotational band in 82 Rb is populated by the 60 Ni(27 Al,4pn) 82 Rb reaction,and the time-integral Larmor precessions are measured after recoil implantation into a polarized Fe foil.The calculation of g-factors is also carried out in terms of a semi-classical model of independent particle angular momentum coupling on the basis of the four-quasiparticle configuration π(g 9/2) 2  π(p 3/2,f 5/2)  ν (g 9/2).The measured and calculated g-factors are in good agreement with each other.The g-factors and deduced shear angles decrease with the increase of spin along the band.This clearly illustrates the shear effect of a step-by-step alignment of the valence protons and neutrons in magnetic rotation.The semi-classical calculation also shows that the alignment of the valence neutron angular momentum is faster than that of the valence protons,which results in a decrease of g-factors with increasing spin.The present results provide solid evidence of the shear mechanism of magnetic rotation.     

核矩测量和核结构研究

简要介绍时间微分扰动角分布、瞬态场-离子注入扰动角分布、β-放射性探测的核磁共振和核电共振等原子核核矩测量方法及其在核结构研究中的应用, 给出了⁴³Sc(19/2^－,3.1232MeV,0.45μs)同质异能态、^84、86Zr和⁸³Y高自旋态、¹⁷F(I=5/2⁺,T_1/2=64.49s)、¹²B和¹²N镜核对的核矩测量和核结构研究例子.     

85MeV19F重离子辐照α–Al2O3的空洞研究

5.28×10¹⁶cm^－2 85MeV¹⁹F辐照的αAl₂O₃中,在其热退火过程中采用正电子湮没方法首次观察到了空洞.450℃退火开始产生空洞,550℃到750℃空洞半径约为0.29nm不随温度变化,但浓度随温度增加而增加;高于750℃,空洞半径随温度升高迅速增大,1050℃时空洞的半径达1.10nm.     

扰动角关联和角分布技术在金属缺陷研究中的应用

超精细相互作用(HFI)是原子核核矩与核外电磁场的相互作用.通过超精细相互作用研究,能够得到原子核的核矩、自旋和原子核周围电荷分布等信息,而研究金属缺陷是超精细相互作用的一个重要应用.研究超精细相互作用的方法很多.用时间微分扰动角关联(TDPAC)和时间微分扰动角分布(TDPAD)方法研究金属缺陷,就是直接测量作用在杂质原子(探针核)上的超精细相互作用,所以灵敏度高,准确性好,是一种微观的研究方法.杂质原子捕获缺陷,引起作用于它的HFI 的变化,在实验中可以观察到不同的HFI图象.缺陷种类、结构和它们在杂质原子周围分布不同,会引…     

Development of β-NMR and β-NQR

The β-NMR (nuclear magnetic resonance) and β-NQR (nuclear quadrupole resonance) technique and its ex-perimental set-up have been developed for the first time in China. The lifetime, magnetic moment and spin polarization of ^12B were determ/ned. The experimental results show the reliability of this newly developed β-NMR and β-NQR set-up.     

g-factors measurement of magnetic rotation band in 85Zr

The magnetic-rotational band in ⁸⁵Zr was populated by the fusion-evaporation reaction ⁶⁰Ni(²⁸Si, 2pn)⁸⁵Zr with a 98 MeV Si beam from the HI-13 tandem accelerator at China Institute of Atomic Energy. The g-factors of the high spin states of this magnetic rotation band in ⁸⁵Zr were measured by the TMF-IMPAD method for the first time. The measured g-factors decrease with the increasing of spin. It implies that the valence neutron alignment is more rapid than that of the valence proton, which leads to a decrease of g-factors along the band.     

Ni离子辐照国产ZIRLO合金的辐照性能研究

国产ZIRLO合金是CAP1400重要的燃料包壳管候选材料之一,因此需要在使用前对该材料进行辐照性能考验。研究了国产ZIRLO合金的辐照性能随辐照温度和损伤剂量的变化。辐照实验在中国原子能科学研究院HI-13串列加速器上,采用80 MeV的Ni离子进行,辐照产生的损伤采用透射电子显微镜、能量色散谱和纳米压痕法等方法表征。国产ZIRLO合金在300℃经10 dpa损伤剂量辐照后观察到均匀分布的析出颗粒,同样剂量在700℃辐照析出颗粒数目减少,析出相的主要成分为Nb。辐照后出现硬化现象,辐照损伤剂量越大,硬化程度越高;随着辐照温度升高,辐照硬化呈减小趋势。The domestic ZIRLO is a promising candidate of cladding materials for CAP1400. It is necessary to test its radiation properties before its use. In this paper, the radiation properties of the domestic ZIRLO have been studied as functions of irradiation temperature and dose respectively. The experiment was performed at the HI-13 tandem accelerator of China Institute of Atomic Energy by using 80 MeV Ni ions at different temperature and different dose. The transmission electron microscopy, electron dispersive spectroscopy and nano-indentation were used to characterize the radiation damage. The experimental results show that the precipitates are uniformly distributed at 10 dpa and 300℃, while at 700℃ the number of precipitates is reduced. Among all the precipitates, Nbisthe dominant element. Hardening phenomenon was also observed after irradiation, the higher the radiation dose, the higher the degree of hardening, and it illustrates a decreasing tendency with the increasing of the irradiation temperature.