The levels in neutron-rich odd-A ^(107,109)Ru nuclei have been investigated by using γ -γ -and γ -γ -γ-coincidence studies of the prompt γ-rays from the spontaneous fission of 252Cf. The ground state bands and t...The levels in neutron-rich odd-A ^(107,109)Ru nuclei have been investigated by using γ -γ -and γ -γ -γ-coincidence studies of the prompt γ-rays from the spontaneous fission of 252Cf. The ground state bands and the negative parity bands are identified and expanded in both nuclei. Triaxial rotor plus particle model calculations indicate the ground state bands originate from v(d_(5/2)+g_(7/2)) quasiparticle configurations and the negative parity bands are from vh_(11/2) orbital.展开更多
Level schemes for the neutron-rich ^(140,143)Ba nuclei have been determined by study of promptγ-rays in spontaneous fission of ^(252)Cf.The level pattern and enhanced E1 transitions betweenπ=+andπ=-bands show refle...Level schemes for the neutron-rich ^(140,143)Ba nuclei have been determined by study of promptγ-rays in spontaneous fission of ^(252)Cf.The level pattern and enhanced E1 transitions betweenπ=+andπ=-bands show reflection asymmetric shapes with simplex quantum number s=+1 in ^(140)Ba and s=±i in ^(143)Ba,respectively.The octupole deformation stability with spin variation has been discussed.展开更多
High spin states in the neutron-rich ^108Mo nucleus are studied by measuring prompt γ-rays following the spontaneous fission of 252Cf with a Gammasphere detector array. The ground-state band is confirmed, and the one...High spin states in the neutron-rich ^108Mo nucleus are studied by measuring prompt γ-rays following the spontaneous fission of 252Cf with a Gammasphere detector array. The ground-state band is confirmed, and the one-phonon γ-vibrational band is updated with spin up to 12h. A new collective band with the band head level at 1422.4keV is suggested as a two-phonon γ-vibrational band. Another new band is proposed as a two-quasi- proton excitation band. Systematic characteristics of the collective bands are discussed.展开更多
Octupole deformation bands built onπh ll/2 orbital in neutron-rich odd-Z 145,147La nuclei have been investigated by measuring the promptγ-rays emitted from the 252Cf source.The alternating parity band structures and...Octupole deformation bands built onπh ll/2 orbital in neutron-rich odd-Z 145,147La nuclei have been investigated by measuring the promptγ-rays emitted from the 252Cf source.The alternating parity band structures and strong E1 transitions observed between negative-and positive-parity bands in both nuclei indicate the octupole deformation enhanced by the h ll/2 single proton coupling.According to observed energy displacements the octupole deformation becomes stable at the intermediate spin states.展开更多
High spin states in neutron-rich odd-N ^(145)Ba nucleus have been investigated from study of promptγ-rays in spontaneous fission of^(252)Cf.The alternating parity bands are identified indicating octupole deformation ...High spin states in neutron-rich odd-N ^(145)Ba nucleus have been investigated from study of promptγ-rays in spontaneous fission of^(252)Cf.The alternating parity bands are identified indicating octupole deformation with simplex quantum number s=-i.The ground state band shows signature splitting and inversion at low spin.These collective band structures exhibit the competition and co-existence between symmetric and asymmetric shapes.展开更多
Levels in the neutron-rich ^(104)Mo nucleus have been investigated by observing promptγ-rays from the spontaneous fission of 252Cf with the Gammasphere detector array.The ground-state band,the one-phonon and the two-...Levels in the neutron-rich ^(104)Mo nucleus have been investigated by observing promptγ-rays from the spontaneous fission of 252Cf with the Gammasphere detector array.The ground-state band,the one-phonon and the two-phononγ-vibrational bands as well as a quasiparticle band have been confirmed and expanded with spin up to 14ħ.Other two side bands probably built on new quasiparticle states are identified.The possible configurations for the quasiparticle bands are discussed.Two of the quasiparticle bands show larger moments of inertia and may have pair-free characteristics.The levels of the ground-state band,the one-phononγ-band and the two-phononγ-band calculated from a general collective model are in close agreement with the experimental data.展开更多
基于Ru(Z=44)丰中子同位素中存在最大三轴形变的理论预言和实验证据,综述了近年来Rh(Z=45),Pd(Z=46),Ag(Z=47),Cd(Z=48)(质子数Z位于Ru,Z=44之上)及Zr(Z=40),Nb(Z=41),Mo(Z=42),Tc(Z=43)(质子数Z位于Ru,Z=44之下)的A～(100～126)丰中子...基于Ru(Z=44)丰中子同位素中存在最大三轴形变的理论预言和实验证据,综述了近年来Rh(Z=45),Pd(Z=46),Ag(Z=47),Cd(Z=48)(质子数Z位于Ru,Z=44之上)及Zr(Z=40),Nb(Z=41),Mo(Z=42),Tc(Z=43)(质子数Z位于Ru,Z=44之下)的A～(100～126)丰中子同位素中关于三轴形变的形状变迁和形状共存系统性研究的重要进展。252Cf自发裂变瞬发γ射线γ-γ-γ三重符合、特别是新建立的γ-γ-γ-γ四重符合数据的系统观测和研究,在Ru,Pd,Cd和Nb丰中子同位素中显著扩展或首次观测到了一系列能带,为这个核区原子核形状的研究提供了新的、重要的实验数据。联系此前报道的有关进展,使用PES,TRS,PSM,CCCSM和SCTAC理论模型计算拟合新的实验数据,在该核区沿同中素和同位素链,并随自旋和激发能变化各自由度,跟踪原子核形状渐进变化,获得了新的系统性研究成果,显著扩展和深化了人们对原子核形状变迁和形状共存的认知。对于Ru及其上的Rh(Z=45),Pd(Z=46),Ag(Z=47)和Cd(Z=48)丰中子同位素的研究表明:Rh丰中子核具有比最大值稍小的三轴形变,γ=-28°,并在103–106Rh同位素链上鉴别出了手征对称破缺;在三轴形变核112Ru和114Pd(N=68)中发现了三轴原子核的摆动运动,该摆动运动也可能在114Ru(N=70)中存在;观察到了从具有最大三轴形变的110,112Ru中手征破缺到稍小三轴形变的112,114,116Pd中扰动的手征破缺的过渡;在较软的Ag核中观察到了丰富的谱学结构,在104,105Ag中鉴别出了可能的手征对称破缺,在较重的115,117Ag中提出了趋于三轴形变的γ软度;具有小形变的Cd核的能级结构被解释为准粒子耦合、准转动和软三轴形变;最近的库伦激发的研究提供了Z=50,N=82满壳附近122,124,126Cd核中出现核集体性的实验和理论证据;上述研究成果展现出从Ru中的最大三轴形变(γ=-30°,三轴形变极小增益为0.67 Me V),经具有大三轴形变的Rh核(γ=-28°),到Pd核中的稍小、但�展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.19775026the Science Foundation for Nuclear Industry of China under Grant No.Y7197AY509the U.S.Department of Energy under Grant Nos.DE-FG05-88ER40407 and DE-FG03-87ER40323.
文摘The levels in neutron-rich odd-A ^(107,109)Ru nuclei have been investigated by using γ -γ -and γ -γ -γ-coincidence studies of the prompt γ-rays from the spontaneous fission of 252Cf. The ground state bands and the negative parity bands are identified and expanded in both nuclei. Triaxial rotor plus particle model calculations indicate the ground state bands originate from v(d_(5/2)+g_(7/2)) quasiparticle configurations and the negative parity bands are from vh_(11/2) orbital.
基金Supported by the National Natural Science Foundation of China under Grant No.19375029the Science Foundation for Nuclear Industry,China under Grant No.J94AY5072the U.S.Department of Energy under Grant Nos.DE-FG05-88ER40407 and DE-FG03-87ER40323.
文摘Level schemes for the neutron-rich ^(140,143)Ba nuclei have been determined by study of promptγ-rays in spontaneous fission of ^(252)Cf.The level pattern and enhanced E1 transitions betweenπ=+andπ=-bands show reflection asymmetric shapes with simplex quantum number s=+1 in ^(140)Ba and s=±i in ^(143)Ba,respectively.The octupole deformation stability with spin variation has been discussed.
基金Supported by the National Natural Science Foundation of China under Grant No 10575057, 10375032, the Special Program of Higher Education Science Foundation under Grant No 200003090. the U. S. Department of Energy under Grant and Contract No DE-FG05-88ER40407 and DE-AC03-76SF00098.
文摘High spin states in the neutron-rich ^108Mo nucleus are studied by measuring prompt γ-rays following the spontaneous fission of 252Cf with a Gammasphere detector array. The ground-state band is confirmed, and the one-phonon γ-vibrational band is updated with spin up to 12h. A new collective band with the band head level at 1422.4keV is suggested as a two-phonon γ-vibrational band. Another new band is proposed as a two-quasi- proton excitation band. Systematic characteristics of the collective bands are discussed.
基金Supported by the National Natural Science Foundation of China under Grant No.19775026the Science Foundation for Nuclear Industry of China under Grant No.Y7197AY509the U.S.Department of Energy under Grant Nos.DE-FG05-88ER40407 and DE-FG03-87ER40323.
文摘Octupole deformation bands built onπh ll/2 orbital in neutron-rich odd-Z 145,147La nuclei have been investigated by measuring the promptγ-rays emitted from the 252Cf source.The alternating parity band structures and strong E1 transitions observed between negative-and positive-parity bands in both nuclei indicate the octupole deformation enhanced by the h ll/2 single proton coupling.According to observed energy displacements the octupole deformation becomes stable at the intermediate spin states.
基金Supported by the National Natural Science Foundation of China under Grant No.19775026the Science Foundation for Nuclear Industry of China under Grant No.Y7197AY509the U.S.Department of Energy under Grant Nos.DE-FG05-88ER0407 and DE-FG03-87ER40323.
文摘High spin states in neutron-rich odd-N ^(145)Ba nucleus have been investigated from study of promptγ-rays in spontaneous fission of^(252)Cf.The alternating parity bands are identified indicating octupole deformation with simplex quantum number s=-i.The ground state band shows signature splitting and inversion at low spin.These collective band structures exhibit the competition and co-existence between symmetric and asymmetric shapes.
基金Supported by the National Natural Science Foundation of China under Grant No.19975028the Science Foundation of China for Nuclear Industry under Grant No.Y7197AY509+1 种基金the Major State Basic Research Development Program of China under Contract No.G2000077400the U.S.Department of Energy under Grant No.DE-FG05-88ER40407.
文摘Levels in the neutron-rich ^(104)Mo nucleus have been investigated by observing promptγ-rays from the spontaneous fission of 252Cf with the Gammasphere detector array.The ground-state band,the one-phonon and the two-phononγ-vibrational bands as well as a quasiparticle band have been confirmed and expanded with spin up to 14ħ.Other two side bands probably built on new quasiparticle states are identified.The possible configurations for the quasiparticle bands are discussed.Two of the quasiparticle bands show larger moments of inertia and may have pair-free characteristics.The levels of the ground-state band,the one-phononγ-band and the two-phononγ-band calculated from a general collective model are in close agreement with the experimental data.
基金The US Department of Energy Grants(DE-FG05-88ER40407,DE-FG02-95ER40934,DE-FG02-95ER40939,DE-FG05-87ER40311)and Contract(W-7405-ENG48,DE-AC03-76SF00098,DE-AC07-99ID13727,DE-AC07-761DO1570)The Work at Tsinghua University was supported by National Natural Science Foundation of China(19775028,10375032,10775078)by Major State Basic Research Development Program of China(2007CB815005,G2000077400)~~
基金US Depart ment of Energy Grants(DE-FG05-88ER40407,DE-FG02-96ER40983,DE-FG02-95ER40093)Contract(W-7405-ENG48,DE-AC03-76SF00098,DE-AC07-76ID01570)+1 种基金The Work at Tsinghua University was supported by National Natural Science Foundation of China(10575057,10775078)Major State Basic Research Development Program of China(2007CB815005)~~
基金US Department of Energy(DE-FG-05-88ER40407,DE-AC02-05CH11231,DE-FG02-95ER40934,DE-AC05-00OR22725,DE-AC52-07NA27344,DE-FG02-95ER40939)National Natural Science Foundation of China(11175095,10975082,11235001,11320101004,11305059,11275063,11275068,11135005,11075103)+2 种基金Special Program of Higher Education Science Foundation(2010000211007)National Basic Research Program of China(973 Program)(2013CB834401)Russian Foundation for Basic Research(11-02-12050,11-02-12066)~~
文摘基于Ru(Z=44)丰中子同位素中存在最大三轴形变的理论预言和实验证据,综述了近年来Rh(Z=45),Pd(Z=46),Ag(Z=47),Cd(Z=48)(质子数Z位于Ru,Z=44之上)及Zr(Z=40),Nb(Z=41),Mo(Z=42),Tc(Z=43)(质子数Z位于Ru,Z=44之下)的A～(100～126)丰中子同位素中关于三轴形变的形状变迁和形状共存系统性研究的重要进展。252Cf自发裂变瞬发γ射线γ-γ-γ三重符合、特别是新建立的γ-γ-γ-γ四重符合数据的系统观测和研究,在Ru,Pd,Cd和Nb丰中子同位素中显著扩展或首次观测到了一系列能带,为这个核区原子核形状的研究提供了新的、重要的实验数据。联系此前报道的有关进展,使用PES,TRS,PSM,CCCSM和SCTAC理论模型计算拟合新的实验数据,在该核区沿同中素和同位素链,并随自旋和激发能变化各自由度,跟踪原子核形状渐进变化,获得了新的系统性研究成果,显著扩展和深化了人们对原子核形状变迁和形状共存的认知。对于Ru及其上的Rh(Z=45),Pd(Z=46),Ag(Z=47)和Cd(Z=48)丰中子同位素的研究表明:Rh丰中子核具有比最大值稍小的三轴形变,γ=-28°,并在103–106Rh同位素链上鉴别出了手征对称破缺;在三轴形变核112Ru和114Pd(N=68)中发现了三轴原子核的摆动运动,该摆动运动也可能在114Ru(N=70)中存在;观察到了从具有最大三轴形变的110,112Ru中手征破缺到稍小三轴形变的112,114,116Pd中扰动的手征破缺的过渡;在较软的Ag核中观察到了丰富的谱学结构,在104,105Ag中鉴别出了可能的手征对称破缺,在较重的115,117Ag中提出了趋于三轴形变的γ软度;具有小形变的Cd核的能级结构被解释为准粒子耦合、准转动和软三轴形变;最近的库伦激发的研究提供了Z=50,N=82满壳附近122,124,126Cd核中出现核集体性的实验和理论证据;上述研究成果展现出从Ru中的最大三轴形变(γ=-30°,三轴形变极小增益为0.67 Me V),经具有大三轴形变的Rh核(γ=-28°),到Pd核中的稍小、但�
