质子滴线区新核素25P的鉴别

在兰州放射性束流装置RIBLL上 ,利用磁刚度B_ρ、飞行时间t_TOF和多重望远镜ΔE- E联合探测方法测量了69Me V/u 36Ar轰击Be靶产生的 P同位素碎片的同位素分布,并与 EPAX经验公式的计算结果进行了比较 ,在质子滴线区首次鉴别出了新核素25PThe mass distribution of the phosphor fragments induced by projectile fragmentation reaction of 69 MeV/u 36Ar + 9Be was measured at the projectile fragment separator RIBLL at IMP. The fragment products were identified by determining the magnetic rigidity Bρ , the time of flight t_TOF and their energy loss ΔE . The experimental isotope distribution was compared to the result of the empirical parameterization EPAX. Three events for the new nuclide 25P in the...     

Structure study of light unbound nuclei near drip line

Some experimental techniques and theoretical analysis on unbound nuclei structure study are briefly introduced in this article. The unbound nuclei structure investigation can inspect the reliability of theoretical calculation, and is also important to extend the modern nuclear structure model to exotic nuclear regions. With the recent development of radioactive Ion Beam (RIB) facility and some new experimental methods, the structure of unbound nuclei near drip line can be studied in experiment.     

兰州放射性束流线

兰州放射性束流线（RIBLL）是产生中能重离子放射性束流（RIB）的装置和高精度放射性束物理的实验谱仪．RIBLL的立体角接收度＞65msr、动量接收度达10％;RIBLL可提供极化RIB;RIBLL采用大接收度双消色差反对称结构,既可纯化放射性束,还可作为0°磁谱仪． Radioactive Ion Beam Line in Lanzhou (RIBLL) is a facility to produce intermediate energy radioactive ion beams (RIB), and also a high precision spectrometer for RIB physical experiments. The solid angle acceptance of RIBLL is 6. 5 msr. The momentum acceptance is about 10%. The polarized RIBs will be available. RIBLL is the equipment with double achromatic and asymmetric structure. So that it can not only sublimate the RIBs in pureness, but also operate as 0° magnet spectrometer.     

在放射性束装置上进行新核素鉴别及其衰变性质的研究

综述了近年来在放射束装置上进行新核素鉴别及其衰变性质研究取得的一些成果, 并简要介绍了即将在兰州放射性束装置上开展的奇异核衰变性质的研究工作． The progresses of new isotope identification and decay property studies on radioactive nuclear beam facilities are reviewed. Studies of the decay properties of exotic nuclei that will be performed at RIBLL are briefly introduced.     

放射性核束物理与核天体物理

基于兰州重离子加速器国家实验室 (HIRFL )的中能放射性核束线 (RIBLL)及北京串列加速器国家实验室 (HI- 1 3 )的低能放射性核束线 (GIRAFFE) ,开展放射性核束物理和核天体物理研究 ,拟解决的关键科学问题是 :远离β稳定线核的结构与反应 ;超重新核素及近滴线核素的合成和性质研究 ,极端同位旋非对称核物质特性和关键的天体核反应研究 .研究内容分成 7个课题 :(1 )晕核研究 ;(2 )新核素合成及超重新核素研究 ;(3 )丰中子核结构和反应 ;(4)丰质子核结构和反应 ;(5 )高自旋的同位旋相关性 ;(6 )关键天体核反应 ;(7)系统的理论研究 .上述研究也将是2005年建成的国家大科学工程——兰州冷却贮存环的主要科学目标的研究基础 .简述了近期的主要工作进展. Based on the intermediate energy radioactive Ion Beam Line in Lanzhou (RIBLL) of Heavy Ion Research Facility in Lanzhou(HIRFL) and Low Energy Radioactive Ion Beam Line (GIRAFFE) of Beijing National Tandem Accelerator Lab (HI-13) the radioactive ion beam physics and nuclear astrophysics will be researched in detail. The key scientific problems which will be researched as high priority are: the nuclear structure and reaction for nucleus far from β-stability line; the syntheses...     

A phenomenological equation of state for isospin asymmetric nuclear matter

A phenomenological momentum-independent(MID) model is constructed to describe the equation of state(EOS) for isospin asymmetric nuclear matter,especially the density dependence of the nuclear symmetry energy Esym(ρ).This model can reasonably describe the general properties of the EOS for symmetric nuclear matter and the symmetry energy predicted by both the sophisticated isospin and momentum dependent MDI model and the Skyrme-Hartree-Fock approach.We find that there exists a nicely linear correlation betwee...     

Development of Silicon Multi-strip Detector

Position sensitive detector is very important for nuclear physics experiment. There several techniques can be used to fabricate position sensitive detector, for example, Si-surface barrier method, diffusion method, ion implantation and planar process etc. Among all the techniques mentioned above planar process is the best one. We have developed batch of position sensitive detector -- silicon multi-strip detector by using planar process.     

Experiment of constraining symmetry energy at supra-saturation density with π~-/π~+ at HIRFL-CSR

The possibility of the experiment for constraining the symmetry energy Esym(ρ) at supra-densities via π-/π+ probe on the external target experiment of phase I ( ETE(I) ) with part coverage at forward angle at HIRFL-CSR is studied for the first time by using the isospin and momentum dependent hadronic transport model IBUU04. Based on the transport simulation with Au+Au collisions at 400 MeV/u, it is found that the differential π-/π+ ratios are more sensitive to Esym(ρ) at forward angles in laboratory reference, compared with the total yield ratio widely proposed. The insufficient coverage at lower transverse momentum maintains the sensitivity of the dependence of π-/π+ ratio on the Esym(ρ) at high density, indicating that the ETF (I) under construction in Lanzhou provides the possibility of performing the experiment for probing the asymmetric nuclear equation of state.     

Spin-Polarized States of Nuclear Matter

The equations of state of spin-polarized nuclear matter and pure neutron matter are studied in theframework of the Brueckner-Hartree-Fock theory including a three-body force. The energy per nucleon E A (δ) calculatedin the full range of spin polarization δ = (ρ↑ - ρ↓)/ρ for symmetric nuclear matter and pure neutron matter fulfills aparabolic law. In both the cases the spin-symmetry energy is calculated as a function of the baryonic density alongwith the related quantities such as the magnetic susceptibility and the Landau parameter Go. The main effect of thethree-body force is to strongly reduce the degenerate Fermi gas magnetic susceptibility even more than the value withonly two-body force. The equation of state is monotonically increasing with the density for all spin-aligned configurationsstudied here so that no any signature is found for a spontaneous transition to a ferromagnetic state.     

拟定中的RIBLL实验装置

建议在兰州放射性束流线（ Ｒ Ｉ Ｂ Ｌ Ｌ）上建设３ 套装置: 直接反应精细测量装置, 用来对放射性束的粒子的运动轨迹逐一进行跟踪, 以及对粒子的电荷态、核电荷数、质量数和能量进行精确跟踪, 从而得到核反应和核结构的准确信息; 磁谱探测系统, 它是由一个二极磁铁和相关真空室组成, 一方面它是一个谱仪系统, 用来分离原始放射性主束和次级反应产物, 进行粒子种类和能量的测量, 另一方面, 还可以用来研究放射性核的电磁矩和基态组态; 奇异衰变的４π探测装置是由５套大面积位置灵敏薄片硅探测器和 Ｃｓ Ｉ（ Ｔｌ）组成的望远镜组, 可覆盖整个探测空间的６０％ ～７０％ ,外加多个塑料中子探测器或 γ探测器, 用来测量奇异核和蒸发余核的关联粒子发射, 寻找和测量奇异的放射性衰变．Radioactive Ion Beam Line in Lanzhou (RIBLL) is able to produce hundreds of radioactive ion beams, by mean of projectile fragmentation. A high performance setup for nuclear direct reaction was promoted to track the radioactive ion, and to measure its charge states, nuclear charge, mass, energy. It benefits precise experiment of both nuclear reaction and nuclear structure. An experimental magnet, composing by dipole magnet and vacuum chamber, should be used as magnetic spectrometer to ...