基于大科学装置的放射性新核素产生进展

Progress in the Production of New Radioactive Nuclides Based on Large-Scale Scientific Facilities

放射性新核素的产生是核物理研究的热点,它对于扩展核素版图、研究奇异核结构和性质、理解核天体物理中的快中子俘获过程都非常重要。目前,人们有关原子核的认识主要集中在稳定线附近长寿命的核素,并建立了多套模型用以解释其基本性质,但对于远离稳定线的核素,特别是重区丰中子核的研究还很缺乏。本文结合国内外产生放射性同位素大科学装置的主要特点和科学目标,总结近年来国际上新核素的发现及其主要产生方法,为将来放射性同位素,尤其是超重核的研究提供参考。

The production of new radioactive nuclides is a hot topic of nuclear physics in recent years,which is essential for expanding the nuclide landscape,studying the structure and properties of exotic nuclei,and understanding the rapid neutron capture process in nuclear astrophysics.The understanding of atomic nuclei is mainly focused on long-lived nuclides near the stability line,and several sets of models have been established to explain their fundamental properties.However,there is a lack of research on nuclides far from the stability line,especially for the neutron-rich nuclei in heavy mass region.The main features and scientific objectives of various international large-scale scientific facilities are introduced in this paper,such as HIRFL(Heavy Ions Research Facility)in Lanzhou,HIAF(High Intensity heavy-ion Accelerator Facility)in Huizhou,ISOL(Isotope Separator Online facility)in Beijing,DRIBs(Dubna Radioactive Ion Beam accelerator complex)in Dubna,88-inch cyclotron in Berkeley,NSCL(National Superconducting Cyclotron Laboratory)in MSU(Michigan State University),ATLAS(Argonne Tandem-Linac Accelerator System)in Argonne,FAIR(Facility for Antiprotons and Ion Research),RARF(RIKEN Accelerator Research Facility)in RIKEN and SPIRAL2(Système de Production d’Ions Radioactifs en Ligne-2)in GANIL,etc.An overview of the discovery of new nuclides and their main production methods in recent years is given,which provides important references for study of radioactive nuclides in the future,especially for super-heavy nuclei.Fusion evaporation reaction mechanism is a significant method for the synthesis of super-heavy nuclei.At present,almost all of the super-heavy nuclei were synthesized by that method.However,due to the limitation of the number of available stable projectiles,the nuclides produced by fusion reaction are all neutron-deficient.In recent years,the multinucleon transfer reactions have attracted extensive attention.Experimental and theoretical studies show that multinucleon transfer reaction is a promising way to produce neutron-rich nuclei.