The lifetimes of a decays of the recently produced isotopes of the elements 112, 114, 116 and the element ^294118 and of some decay products have been calculated theoretically within the Wentzel-Kramers-Brillouin appr...The lifetimes of a decays of the recently produced isotopes of the elements 112, 114, 116 and the element ^294118 and of some decay products have been calculated theoretically within the Wentzel-Kramers-Brillouin approximation. The a decay barriers have been determined in the quasimolecular shape path within a generalized liquid drop model including the proximity effects between nuclei in a neck, the mass and charge asymmetry and the precise nuclear radius. These calculations provide reasonable estimates for the observed a decay lifetimes. The calculated results have been compared with the results of the density-dependent M3Y effective interaction and the experimental data. It is indicated that the theoretical foundation of the generalized liquid drop model is as good as that of the microscopic DDM3Y model, at least in the sense of predicting the T1/2 values as long as one uses a correct a decay energy. The half lives of these new nuclei are well tested from the consistence of the macroscopic, the microscopic and the experimental data.展开更多
At RIKEN,three ECR ion sources(10GHz ECRIS,18GHz ECRIS and liquid He-free SC-ECRIS) are operated as external ion sources of heavy ion accelerators.In the last year,multi-charged uranium ion beam was produced from 18GH...At RIKEN,three ECR ion sources(10GHz ECRIS,18GHz ECRIS and liquid He-free SC-ECRIS) are operated as external ion sources of heavy ion accelerators.In the last year,multi-charged uranium ion beam was produced from 18GHz ECRIS by using UF_6 and the ^(238)U ion was successfully accelerated by the accelerator complex which consists of the RFQ linear accelerator,RIKEN heavy ion linear accelerator(RILAC)and RIKEN ring cyclotron accelerator(RRC).The typical beam intensity of^(238)U^(14+) was about 2pμA on faraday cup after analysing magnet.^(70)Zn beam was still supplied for the new super-heavy element search experiment with insertion method.Intense beam of^(70)Zn^(16+) was produced for long term(～43 days)without vacuum break and remarkably low material consumption rate(～100μgr/h).We already supplied Zn beam longer than 200 days for this experiment.^(48)Ca ion was also produced by insertion method using^(48)CaO rod for the nuclear physics experiment.In this contribution,we will present ion source parameter and techniques for production of each of the metal ions.展开更多
基金Supported by the Major State Basic Research and Development Programme of China under Contract No G2000077400, the National Natural Science Foundation of China under Grant Nos 10505016, 10235020, 10235030, 10275094, 10075080 and 10575119, the Knowledge Innovation Project of Chinese Academy of Sciences under Grant No KJCX2-SW-N02, National Key Programme for Basic Research of the Ministry of Science and Technology under Grant Nos 2001CCB01200 and 2002CCB00200, and the DFG of Germany.
文摘The lifetimes of a decays of the recently produced isotopes of the elements 112, 114, 116 and the element ^294118 and of some decay products have been calculated theoretically within the Wentzel-Kramers-Brillouin approximation. The a decay barriers have been determined in the quasimolecular shape path within a generalized liquid drop model including the proximity effects between nuclei in a neck, the mass and charge asymmetry and the precise nuclear radius. These calculations provide reasonable estimates for the observed a decay lifetimes. The calculated results have been compared with the results of the density-dependent M3Y effective interaction and the experimental data. It is indicated that the theoretical foundation of the generalized liquid drop model is as good as that of the microscopic DDM3Y model, at least in the sense of predicting the T1/2 values as long as one uses a correct a decay energy. The half lives of these new nuclei are well tested from the consistence of the macroscopic, the microscopic and the experimental data.
文摘At RIKEN,three ECR ion sources(10GHz ECRIS,18GHz ECRIS and liquid He-free SC-ECRIS) are operated as external ion sources of heavy ion accelerators.In the last year,multi-charged uranium ion beam was produced from 18GHz ECRIS by using UF_6 and the ^(238)U ion was successfully accelerated by the accelerator complex which consists of the RFQ linear accelerator,RIKEN heavy ion linear accelerator(RILAC)and RIKEN ring cyclotron accelerator(RRC).The typical beam intensity of^(238)U^(14+) was about 2pμA on faraday cup after analysing magnet.^(70)Zn beam was still supplied for the new super-heavy element search experiment with insertion method.Intense beam of^(70)Zn^(16+) was produced for long term(～43 days)without vacuum break and remarkably low material consumption rate(～100μgr/h).We already supplied Zn beam longer than 200 days for this experiment.^(48)Ca ion was also produced by insertion method using^(48)CaO rod for the nuclear physics experiment.In this contribution,we will present ion source parameter and techniques for production of each of the metal ions.
