A-90区核高自旋态g-因子测量及其对核结构的预测
摘要
过渡性核的高自旋态核结构是当前核物理研究重要而活跃的领域之
一。A～90，Z＜40的核具有较大的四极形变，而Z 40的核是介于形变核
和球形核之间的过渡性核。
过渡性核的结构呈现出集体运动、振动激发、单粒子激发和核芯形变
等几个自由度相互作用的特点。单粒子能隙随粒子数和角动量而改变，并
出现形状共存和迅速的形状演变，因而这些形变小而软的过渡性核的高自
旋态核结构复杂，其核结构研究可以更深刻地揭示原子核的结构。
原子核g-因子是表征核性质的重要的基本物理量之一，从g-因子可
以获得直接的核结构信息，对核结构作出结论性的判断。在中国原子能科
学研究院HI—13串列加速器上建立了用于寿命为ns-μs量级的核态g-
因子测量的时间微分扰动角分布谱仪和寿命为ps量级的核态g-因子测
量的瞬态场离子注入扰动角分布谱仪，并进行了两次g-因子测量的实
验。
过渡性核高自旋态的寿命绝大部分是10~(-13)—10~(-10)秒（ps量级）我们
采用瞬态场离子注入扰动角分布的方法对这一类核态进行了测量。核反应
产生的剩余核高速通过极化的Fe箔后停止在立方晶格的阻挡层中，在其
通过Fe时受到高达10~7G的瞬态磁场作用，角分布受到扰动。通过拉摩尔
进动角公式Δθ=gBtμ_n/h可以得到g-因子表达式。利用对应于不同自旋
态的退激γ谱线，我们可以得到不同自旋态的g-因子。
In recent years, the nuclear structure of transitional nuclei in high spin
states has been one of the most important and actiVe fields in the study of
nuclear physics. The nuclei (A-.-90,z<40) have very large quadrupolar
deformations, while the nuclei(Z40) are the transitional nuclei between
deformational nuclei and spherical ones.
The structure of transitional nuclei shows the characteristics of the
interaction of several free degrees such as collective motion, vibrational
excitation, single particle excitation and nuclear core deformation. The
magnitude of single particle energy gap changes with particle number and
angular momentum. Shape coexistence and rapid shape evolvement also
emerge. So these soft transitional nuclei with tiny deformations in high spin
states have complex structures, and the studies of which are helpful to the
further exploration and understanding of the atomic nuclear structures.
The g factor of atomic nucleus is one of the most important and basic
physical qualities, from which many nuclear structure informations can be
achieved directly and the conclusive judgements can also be made. On the HI-
13 tandem accelerator of China Institute of Atomic Energy, we have set up the
time-differential-perturbation-angular-distribution-spectrometer for the gactor
measurement of nuclear states of ns-ts level life-times and the transient-field-
ion-infuse-perturbation-angular-distribution-spectrometer for the g-factor
measurement of nuclear states of ps level life-times. We performed twice
experiments of g-factor measurement by using the latter.
The life-times of most transitional nuclear high spin states are 1 o 010
second (ps level) , we adopted the method of transitional field-ion-infuse-
perturbation-angular-distribution to measure g-factors for these states. In the
experiment the residual nuclei produced by nuclear reactions will rush through
the polarized Fe foil at high speed and stop at the cubic crystal stopping layer.
When they rush through polarized Fe, they are impacted by the transitional
field as high as I 07G, so the angular distributions are perturbed We can derive
the g-factors formalism from Lamar procession angle A 0 = gBt,u/ h and g-
factor corresponding to different spin state can be obtained by analyzing I
spectrum of different spin states.
一。A～90，Z＜40的核具有较大的四极形变，而Z 40的核是介于形变核
和球形核之间的过渡性核。
过渡性核的结构呈现出集体运动、振动激发、单粒子激发和核芯形变
等几个自由度相互作用的特点。单粒子能隙随粒子数和角动量而改变，并
出现形状共存和迅速的形状演变，因而这些形变小而软的过渡性核的高自
旋态核结构复杂，其核结构研究可以更深刻地揭示原子核的结构。
原子核g-因子是表征核性质的重要的基本物理量之一，从g-因子可
以获得直接的核结构信息，对核结构作出结论性的判断。在中国原子能科
学研究院HI—13串列加速器上建立了用于寿命为ns-μs量级的核态g-
因子测量的时间微分扰动角分布谱仪和寿命为ps量级的核态g-因子测
量的瞬态场离子注入扰动角分布谱仪，并进行了两次g-因子测量的实
验。
过渡性核高自旋态的寿命绝大部分是10~(-13)—10~(-10)秒（ps量级）我们
采用瞬态场离子注入扰动角分布的方法对这一类核态进行了测量。核反应
产生的剩余核高速通过极化的Fe箔后停止在立方晶格的阻挡层中，在其
通过Fe时受到高达10~7G的瞬态磁场作用，角分布受到扰动。通过拉摩尔
进动角公式Δθ=gBtμ_n/h可以得到g-因子表达式。利用对应于不同自旋
态的退激γ谱线，我们可以得到不同自旋态的g-因子。
In recent years, the nuclear structure of transitional nuclei in high spin
states has been one of the most important and actiVe fields in the study of
nuclear physics. The nuclei (A-.-90,z<40) have very large quadrupolar
deformations, while the nuclei(Z40) are the transitional nuclei between
deformational nuclei and spherical ones.
The structure of transitional nuclei shows the characteristics of the
interaction of several free degrees such as collective motion, vibrational
excitation, single particle excitation and nuclear core deformation. The
magnitude of single particle energy gap changes with particle number and
angular momentum. Shape coexistence and rapid shape evolvement also
emerge. So these soft transitional nuclei with tiny deformations in high spin
states have complex structures, and the studies of which are helpful to the
further exploration and understanding of the atomic nuclear structures.
The g factor of atomic nucleus is one of the most important and basic
physical qualities, from which many nuclear structure informations can be
achieved directly and the conclusive judgements can also be made. On the HI-
13 tandem accelerator of China Institute of Atomic Energy, we have set up the
time-differential-perturbation-angular-distribution-spectrometer for the gactor
measurement of nuclear states of ns-ts level life-times and the transient-field-
ion-infuse-perturbation-angular-distribution-spectrometer for the g-factor
measurement of nuclear states of ps level life-times. We performed twice
experiments of g-factor measurement by using the latter.
The life-times of most transitional nuclear high spin states are 1 o 010
second (ps level) , we adopted the method of transitional field-ion-infuse-
perturbation-angular-distribution to measure g-factors for these states. In the
experiment the residual nuclei produced by nuclear reactions will rush through
the polarized Fe foil at high speed and stop at the cubic crystal stopping layer.
When they rush through polarized Fe, they are impacted by the transitional
field as high as I 07G, so the angular distributions are perturbed We can derive
the g-factors formalism from Lamar procession angle A 0 = gBt,u/ h and g-
factor corresponding to different spin state can be obtained by analyzing I
spectrum of different spin states.
引文
[1．1]卢希廷，原子核物理，原子能出版社(1981)．
[1．2]徐四大，原子核物理，清华大学出版社(1987)
[1.3]Harder A, Kabadiyski M K, Lieb K P et al., Phys. Rev., C51,2932-2941(1995)
[1.4]Kaye R A, Doring J, Holcomb J W et al., Phys. Rev.,C54, 1038-1056(1996)
[1.5]Doring J, Winter G, Funke L et al., Phys Rev., C46,R2127-R2131(1992)
[1.6]Jain H C. Nulclear Shapes In Mass-80 Region. In:Eswaran M A, Chcudhury R K. India:Department of Atomic Energy,279-287(1993)
[1.7]Winter G, Schwengner R, Reif J et al., Phys. Rev.,C49,2427-2439(1994)
[1.8]郑华，硕士论文，1991
[1.9]P.Chowdhury, C.J.Lister, D.J.Blumenthal, B.Crowell, T.Drke, P.J.Ennis, A.Galindo-Uribarri, D.Horn, J.K.Johansson, A.Omer, S.Pillott, D.Prevost, D.Radford, J.C.Waddington, and D.Ward,Phys. Rev. Lett.67,2950(1991 )
[1.10]韩广兵，硕士论文，1999
[1.11]F.S. Stephen et al., Nucl. Phys.,A183,257(1972)
[1.12]I.Y.Lee et al., Phys. Rev. Lett., 38,1454(1977)
[2.1]A I Kucharska,J Billowes,C J Lister,Phys. G:Nucl.part. Phys.15(1989) 1039-1051.Printed in the UK
[2.2]A.W.Mountford, T.Vass,G.Kumbartzki,L.A.Bernstein,and N.BenczerKolle, Physical Review C.Volume 51.Number 2.February.(1995)
[2.3]N.K. Shu,D,Melnik,J.M.Brennan,W.Semmler, and N. Benczer-koller, Phys. Rev. C21 (1980) 1828
[2． 4] A. W. Mountford,J. Billowes, Phys.Lett. B279(1992) 228-232
[3． 1] V. Zobel et al., Nucl. Instrum.Methods 171(1980) 223
[3． 2] , 1991
[3． 3] T. A. Doron, and M. Blann, Nuclear physics A161(1971) 12-48
[3． 4] H. A. Enge,Introduction to Nuclear Physics, Addison-Wesley Publishing Co Inc ,Reading, Mass. (1966)
[3． 5] L. R. B. Elton, Introduction Nuclear theory,2-ed, London Sir Isaac, pitman and Sons. Ltd .(1964)
[3． 6] H. Franenfelder and E. M. Henley Subatomic Physics,PrenticeHall,inc,E-nglewood Cliffs,New Jersey(1974)
[3． 7] K. H. Beckurts,K. wirtz, Neutron Physics, New York.(1964)
[3． 8] M. G. Mayer and J. H. D. Jensen, Elementary Theory of Nuclear Shell Structure, Wiley,New York.(1995)
[4． 1] A. I. Kucharska,J. Billowes,C. J. Lister,Phys.G:Nucl.part.Phys.l5 (1989) 1039-1051． Printed in the UK
[4． 2] C.Teich, A.Jungelaus, V.Fischer, D.Kast, Kast, K.P.Lieb, and C.Lingk, Physical Review C,Volume 59,Number 4,April (1999)
[5． 1] S. L. Tabor,J. W. Holcomb,G. D. Johnson,T. J. Petters,M. A.Riley,and P-C.Wo mble,Physical Review.Volume 49． Number 2． February.(1994) .
[5． 2] E. K. Warburton,C. J.Lister,J. W.Olness,P. E. Haustein,S. K. Saha,and D-. E.A1 burger,Physical Review C. Volume 31 .Number 4． April.(1985)
[5． 3] S. L. Tabor,J. W.Holcomb,G. D. Johnson,T. J.Petters,M. A. Riley,and P-.C.Wo-mble,Physical Review.Volume 49． Number 2． February.(1994) .
[5． 4] E.K.Warburton,C.J.Lister,J.W.Olness,P.E.Haustein,S.K.Saha,and D.E.A1-burger,Physical Review C.Volume 31． Number 4． April.(1985)
[1．2]徐四大，原子核物理，清华大学出版社(1987)
[1.3]Harder A, Kabadiyski M K, Lieb K P et al., Phys. Rev., C51,2932-2941(1995)
[1.4]Kaye R A, Doring J, Holcomb J W et al., Phys. Rev.,C54, 1038-1056(1996)
[1.5]Doring J, Winter G, Funke L et al., Phys Rev., C46,R2127-R2131(1992)
[1.6]Jain H C. Nulclear Shapes In Mass-80 Region. In:Eswaran M A, Chcudhury R K. India:Department of Atomic Energy,279-287(1993)
[1.7]Winter G, Schwengner R, Reif J et al., Phys. Rev.,C49,2427-2439(1994)
[1.8]郑华，硕士论文，1991
[1.9]P.Chowdhury, C.J.Lister, D.J.Blumenthal, B.Crowell, T.Drke, P.J.Ennis, A.Galindo-Uribarri, D.Horn, J.K.Johansson, A.Omer, S.Pillott, D.Prevost, D.Radford, J.C.Waddington, and D.Ward,Phys. Rev. Lett.67,2950(1991 )
[1.10]韩广兵，硕士论文，1999
[1.11]F.S. Stephen et al., Nucl. Phys.,A183,257(1972)
[1.12]I.Y.Lee et al., Phys. Rev. Lett., 38,1454(1977)
[2.1]A I Kucharska,J Billowes,C J Lister,Phys. G:Nucl.part. Phys.15(1989) 1039-1051.Printed in the UK
[2.2]A.W.Mountford, T.Vass,G.Kumbartzki,L.A.Bernstein,and N.BenczerKolle, Physical Review C.Volume 51.Number 2.February.(1995)
[2.3]N.K. Shu,D,Melnik,J.M.Brennan,W.Semmler, and N. Benczer-koller, Phys. Rev. C21 (1980) 1828
[2． 4] A. W. Mountford,J. Billowes, Phys.Lett. B279(1992) 228-232
[3． 1] V. Zobel et al., Nucl. Instrum.Methods 171(1980) 223
[3． 2] , 1991
[3． 3] T. A. Doron, and M. Blann, Nuclear physics A161(1971) 12-48
[3． 4] H. A. Enge,Introduction to Nuclear Physics, Addison-Wesley Publishing Co Inc ,Reading, Mass. (1966)
[3． 5] L. R. B. Elton, Introduction Nuclear theory,2-ed, London Sir Isaac, pitman and Sons. Ltd .(1964)
[3． 6] H. Franenfelder and E. M. Henley Subatomic Physics,PrenticeHall,inc,E-nglewood Cliffs,New Jersey(1974)
[3． 7] K. H. Beckurts,K. wirtz, Neutron Physics, New York.(1964)
[3． 8] M. G. Mayer and J. H. D. Jensen, Elementary Theory of Nuclear Shell Structure, Wiley,New York.(1995)
[4． 1] A. I. Kucharska,J. Billowes,C. J. Lister,Phys.G:Nucl.part.Phys.l5 (1989) 1039-1051． Printed in the UK
[4． 2] C.Teich, A.Jungelaus, V.Fischer, D.Kast, Kast, K.P.Lieb, and C.Lingk, Physical Review C,Volume 59,Number 4,April (1999)
[5． 1] S. L. Tabor,J. W. Holcomb,G. D. Johnson,T. J. Petters,M. A.Riley,and P-C.Wo mble,Physical Review.Volume 49． Number 2． February.(1994) .
[5． 2] E. K. Warburton,C. J.Lister,J. W.Olness,P. E. Haustein,S. K. Saha,and D-. E.A1 burger,Physical Review C. Volume 31 .Number 4． April.(1985)
[5． 3] S. L. Tabor,J. W.Holcomb,G. D. Johnson,T. J.Petters,M. A. Riley,and P-.C.Wo-mble,Physical Review.Volume 49． Number 2． February.(1994) .
[5． 4] E.K.Warburton,C.J.Lister,J.W.Olness,P.E.Haustein,S.K.Saha,and D.E.A1-burger,Physical Review C.Volume 31． Number 4． April.(1985)