We investigate the structure of yrast bands in the transuranium nuclei ^(242)Pu and ^(244)Pu in the framework of the projected shell model,which is a fully quantum mechanical and microscopic approach.It is found that ...We investigate the structure of yrast bands in the transuranium nuclei ^(242)Pu and ^(244)Pu in the framework of the projected shell model,which is a fully quantum mechanical and microscopic approach.It is found that an appropriate modification of the standard Nilsson spin-orbital parameters in the N =6 proton shell is necessary to correctly describe the high-spin backbending phenomenon in nucleus ^(244)Pu.In order to test whether this modification is correct,the same modified parameters are used to calculate the yrast band of its neighboring isotope ^(242)Pu.It is found that without this modification,a backbending will occur at spin I =20,which is not supported by the experimental data.展开更多
By bombarding the natural thorium targets with 14 MeVneutrons,^(229)Ra was produced through the reaction ^(232)Th(n,α)^(229)Ra.The radium activities were separated from the irradiated targets by coprecipitation with ...By bombarding the natural thorium targets with 14 MeVneutrons,^(229)Ra was produced through the reaction ^(232)Th(n,α)^(229)Ra.The radium activities were separated from the irradiated targets by coprecipitation with BaC_(12).A total of 18 weak γ rays with energies of 14.5,15.6,18.8,21.8,22.5,44.0,47.5,55.0,63.0,69.6,93.6,94.1,98.5,102.2,104.5,106.1,161.1,and 171.5keV,which could be assigned to the decay of ^(229)Ra,has been observed in the isolated radium fractions employing high-resolution HPGe detectors and γ(x)-γ coincidence methods.A decay scheme of ^(229)Ra based on these observations has been proposed.展开更多
A new transuranium neutron-deficient isotope ^(235)Am was produced via the reaction of ^(238)Pu(p,4n)^(235)Am by using a 35 MeV proton beam.The recoiled products were collected by a helium-jet and long-capillary syste...A new transuranium neutron-deficient isotope ^(235)Am was produced via the reaction of ^(238)Pu(p,4n)^(235)Am by using a 35 MeV proton beam.The recoiled products were collected by a helium-jet and long-capillary system.Americium isotopes were separated out by a rapid radiochemical method.X-ray,γ-ray,and x-γ coincidence measurements were taken in the study.According to ^(235)Pu decay γ-ray and Np K x-ray growth-decay property,^(235)Am was definitely identified and its half life is determined as 15±5 min.展开更多
The new neutron-rich isotope 186Hf has been produced through a multinucleon transfer reaction by irradiation of natural tungsten targets with 60MeV/u ^(18)O projectiles.The ^(186)Hf activities were separated radiochem...The new neutron-rich isotope 186Hf has been produced through a multinucleon transfer reaction by irradiation of natural tungsten targets with 60MeV/u ^(18)O projectiles.The ^(186)Hf activities were separated radiochemically from the tungsten and reaction product mixture.The γ-ray singles spectra were measured with a high resolution HPGe detector.The new isotope ^(186)Hf was identified based on the growth and decay of 737.5 keV γ rays from the β^(-) decay of its daughter ^(186)Ta.Its half-life has been determined to be 2.6±1.2 min.展开更多
基金Supported by Suranaree University of Technology under Grant No 15/2553the National Basic Research Development Program of China under Grant No 2007CB815003the National Natural Science Foundation of China under Grant Nos 10975190,11065001,10975019,10675170 and 61067001.
文摘We investigate the structure of yrast bands in the transuranium nuclei ^(242)Pu and ^(244)Pu in the framework of the projected shell model,which is a fully quantum mechanical and microscopic approach.It is found that an appropriate modification of the standard Nilsson spin-orbital parameters in the N =6 proton shell is necessary to correctly describe the high-spin backbending phenomenon in nucleus ^(244)Pu.In order to test whether this modification is correct,the same modified parameters are used to calculate the yrast band of its neighboring isotope ^(242)Pu.It is found that without this modification,a backbending will occur at spin I =20,which is not supported by the experimental data.
基金Supported by the National Natural Science Foundation of China under Grant No.19375055the 8-5 Great Item in in Chinese Academy of Science under Grant No.KJ85-.
文摘By bombarding the natural thorium targets with 14 MeVneutrons,^(229)Ra was produced through the reaction ^(232)Th(n,α)^(229)Ra.The radium activities were separated from the irradiated targets by coprecipitation with BaC_(12).A total of 18 weak γ rays with energies of 14.5,15.6,18.8,21.8,22.5,44.0,47.5,55.0,63.0,69.6,93.6,94.1,98.5,102.2,104.5,106.1,161.1,and 171.5keV,which could be assigned to the decay of ^(229)Ra,has been observed in the isolated radium fractions employing high-resolution HPGe detectors and γ(x)-γ coincidence methods.A decay scheme of ^(229)Ra based on these observations has been proposed.
基金Supported by the National Natural Science Foundation of China under Grant No.19475052Chinese Academy of Sciences.
文摘A new transuranium neutron-deficient isotope ^(235)Am was produced via the reaction of ^(238)Pu(p,4n)^(235)Am by using a 35 MeV proton beam.The recoiled products were collected by a helium-jet and long-capillary system.Americium isotopes were separated out by a rapid radiochemical method.X-ray,γ-ray,and x-γ coincidence measurements were taken in the study.According to ^(235)Pu decay γ-ray and Np K x-ray growth-decay property,^(235)Am was definitely identified and its half life is determined as 15±5 min.
基金Supported by the National Natural Science Foundation of China under Grant No.19775055,and Chinese Academy of Sciences。
文摘The new neutron-rich isotope 186Hf has been produced through a multinucleon transfer reaction by irradiation of natural tungsten targets with 60MeV/u ^(18)O projectiles.The ^(186)Hf activities were separated radiochemically from the tungsten and reaction product mixture.The γ-ray singles spectra were measured with a high resolution HPGe detector.The new isotope ^(186)Hf was identified based on the growth and decay of 737.5 keV γ rays from the β^(-) decay of its daughter ^(186)Ta.Its half-life has been determined to be 2.6±1.2 min.
