MASS DRIFT IN HEAVY ION REACTION

A simple model by which the mass drift can be expected in heavy ion reaction is suggested. The drift of average value of mass distribution with increasing dissipation energy is very small, because large damping effect hinders the driving potential in the process of energy equilibration while in the process of fast fission the drift of mass distribution increases rapidly and reaches equilibrium which comes from the effect of driving force.     

TWO-BODY EFFECT IN HEAVY ION COLLISION

A simple relaxation equation have been obtained from the master equation of the occupation number by means of the time average approximation in the dissipation diabatic dynamic theory. Contributions from one-body and two-body collision processes to the rate of occupation number have been compared quantitatively.     

重离子束在医学治疗中的应用

重离子束治癌是重离子束在医疗领域中的一项典型的应用技术,文章从重离子束在物理学与生物学上的特点,描述了它对肿瘤治疗具有优越性,物理剂量深度分布在射程末端有一个能量沉积集中区,其深度和大小均可调节;在靶区的相对生物效率（RBE）高、氧增比（OER）低;射程歧离与横向散射小;利用正电子发射断层照相（PET）技术术可以实时在线监测;可以三维扫描进行适用形治疗,半致死损伤修复小;辐射敏感性不依赖细胞周期相,文章还介绍了这项技术的国内外进展,并对其未来进行了展望。     

HEAVY ION COLLISIONS AND QUARK DISTRIBUTION IN NUCLEI

The heavy-ion collisions are studied by means of two-component Fokker-Planck equations on the assumption that there exist multiquark states in nuclei. Inclusive cross section for the production of p is calculated in heavy-ion collisions of C+C, Ne+NaF and Ar+KCI at 800 MeV/N; Ne+NaF at 400 MeV/N, 800 MeV/N and 2100 MeV/N. A satisfactory agreement with the experimental data near c.m. 90 degree is obtained. The production of d in the collision of C+C at 800 MeV/N is also discussed.     

重离子束在等离子体靶中的能量损失

借助于线性Vlasov方程,我们研究了重离子束在等离子体靶中的有效电荷数和电子阻止本领。在高速情况下,分别得到了它们的解析表示式。以~(40)Ga,~(74)Ge,~(84)Kr,~(110)pd,~(208)pb及~(238)U等重离子束在氢等离子体中的能量损失为例,将我们的理论结果与Hoffmann等人的实验结果进行了比较。     

TWO-PION INTERFEROMETRY FOR MULTI-PION EVENTS IN RELATIVISTIC HEAVY ION COLLISIONS

The effect of multi-pion correlations on two-pion interferomentry in a multi-pion event is studied.A new general two-pion interferometry method is developed,by taking into consideration of the effect of multi-pion correlations.Data for 1.8A GeV Ar+Pb central collisions at the Bevalac streamer chamber are analysed by using this new method.     

中能重离子碰撞过程中的同位旋分馏

本文主要在我们近几年来对中能重离子碰撞中同位旋分馏研究工作的基础上,结合国际上对这个问题研究的进展。对同位旋分馏动力学,产生同位旋分馏的机制,入射道效应,特别是建议将同位旋分馏强度作为提取同位旋相关平均场和建立同位旋不对称核物质状态方程的可能性进行了讨论和分析。并进一步对该问题的深入研究进行了讨论。     

MASS DRIFT FLUCTUATION AND THE SHELL EFFECT IN HEAVY ION COLLISIONS

Master equation is solved numerically for mass drift and fluctuation of three reactions.The driven potential is calculated by means of D.Myers' mass formula plus shell correction.The results indicated that the lack of mass drift in the range of zero to a considerable energy loss in heavy ion collisions could be explained by transport theory.Due to small mass mobility coefficient the mass does not drift considerably during a short time interval.The effect of shell structure in the driven potential is obvious for mass relaxation in low energy loss region.     

HEAVY ION TRACK DIAMETERS IN MICA STUDIED WITH SCANNING FORCE MICROSCOPE

In the present study, the scanning force microscope (SFM) was employed to measure the heavy ion track diameters in mica and was operated in the lateral-force mode with different loading forces. The mica samples were irradiated with Se, Au, Pb and Zn ions with a kinetic energy of 11.4 MeV/u at the UNILAC of GSI. The measured average track diameter increased slowly with increasing loading force between the SFM tip and sample. The experimental data pointed out that the track diameter versus loading force could be fitted by a linear function both for Se and Au ion species and the slopes of the fitted lines were nearly the same. By extrapolating to zero loading force, the intrinsic diameters of the ion tracks were obtained. A possible mechanism for the observations was discussed.     

兰州重离子加速器的状态和发展

文章首先简要地介绍了世界上重离子加速器的发展状态,然后对兰州重离子加速器（HRFL）的结构,建造过程,运行情况,多年来以及目前正在进行的主要改造项目进行了描述,为适应核物理及其相关学科的持续发展研究的需要,对HIRFL近期和将来的发展情况作了概括的描述。     

高能重离子碰撞实验中的软物理研究现状

高能重离子碰撞实验中的软物理研究能够帮助我们清楚认识系统的集体演化过程,并且有助于理解碰撞产生的热密系统的性质.本文介绍了高能重离子碰撞实验中软物理的研究现状及其新近取得的实验成果,包括七部分内容:1)高能重离子碰撞简介;2)碰撞几何方面的研究现状;3)粒子产生方面的研究现状;4)关联与起伏方面的研究现状;5)集体膨胀方面的研究现状;6)强子化方面的研究现状,7)LHC/ALICE实验上的软物理预期.最后,本文对高能重离子碰撞实验中的软物理研究现状进行总结.     

同位旋效应对中能重离子反应中轻粒子产物的影响

利用同位旋相关的量子分子动力学模型,研究了¹¹²Sn+¹¹²Sn和¹²⁴Sn+¹²⁴Sn两反应系统在不同入射能量、不同碰撞参数、不同势场和不同核子-核子碰撞截面下的粒子发射特征.阐述了发射体系的同位旋对轻粒子产额比的影响.发现轻粒子产额比是同位旋的敏感观测量.另外,还发现中快度区发射的粒子有更高的丰中子程度.同时,轻粒子的比不敏感于核子核子碰撞截面,而敏感于核态方程,这使得从轻粒子比提取同位旋相关的核态方程变成一种可能. 关键词： 同位旋相关的量子分子动力学 同位旋效应 轻粒子产额比     

ENHANCED NEUTRON EM1SSION IN HEAVY ION REACTIONS BY DIFFUSION MODEL

An extensive Smoluchowski equation with neutron emission is suggested in this paper and is analytically solved by means of van Kampen technique.The average fission rate,fission probability,the ratio of neutron emission to fission are calculated for composite nucleus ²⁴⁰PU. The time evolution of these quantities is analysed and their essential dependence on fission potential height and nuclear temperature are discussed.A fair1y substantial particle evaporation prior to fission in heavy-ion reactions can be well understood in our diffusion model.     

A SIMPLE METHOD OF STUDYING TRANSFER OF ANGLAR MOMENTUM IN HEAVY ION REACTION

This paper has explored the relations among the energy transfer and the linear andanglar momentum transfer in heavy ion reaction from the theoretical point of view.     

A FURTHER EXPLORATION FOR MECHANISM OF ANGULAR MOMENTUM TRANSFER IN HEAVY ION REACTION

The difficulty of the classical dynamics in studing the mechanism of angular momentum transfer is discussed. According to the nuclear rotational concept formed in the study of the nuclear structure for a long time, we point out that it is convenient to divide the total angular momentum I transfered to the target and the projectile into two components-the nuclear collective angular momentum I_R and the rotational alignment angular momentum I_j.     

INVESTIGATION OF THE EFFECT OF NUCLEAR SHORT RANGE CORRELATION IN HEAVY ION SCATTERING

Bassed on the "Rigid Projectile" approximation and the Glauber's multiple scattering theory. The influence of the nuclear short range correlation on elastic scattering of high energy heavy ion is discussed. The elastic α-¹²C scattering at 1.37 GeV is calculated and compared with experimential data. It is show that the influence of the unclear short range correlation on differential cross section is quite important.     

HEAVY ION COLLISION DYNAMICS IN FERMI DOMAIN (I) DYNAMICS DEPENDENCE OF ENERGY

In the case of central collisions,the collision mechanism of complete,incomplete fusion,and fragmentation were systematically studied via the Boltzmann-Uehling-Uhlenbeck theory which included the nuclear mean field dynamics,two-body collisions,and Pauli blocking between 5 and 150MeV/u for ²⁰Ne+²⁰Ne collision system.How the mean field,Pauli blocking of the two-body collisions were affected by bombarding energy and their effect on the reaction mechanism was discussed.     

200KV重离子加速器及其应用

本文介绍一台采用双潘宁型多电荷重离子源的200kV重离子加速器,简述它在GaP光探测器的研制、聚合物材料和金属材料的离子注入改性等方面的研究与应用。     

低能重离子耗散反应产物的激发函数研究

述评低能重离子耗散碰撞激发函数中截面涨落现象的主要实验结果：截面及其涨落的不可平滑性、不可重复性以及大角度之间的长程能量关联；述评与实验结果相应的理论研究进展：用双核系统的衰变、相干转动以及相位无规化过程这样三种不同运动形态的相互复杂作用定量描述耗散反应随时间的演化。     

Penning阱中离子谱的优化

根据Penning阱存储离子的探测原理,系统分析了阱内离子信号及信号本身的噪声、实验仪器及探测电路的噪声干扰,采用适当的品质因数和电子束流,得到较高信噪比和分辨率的离子谱。为深入开展Hn^＋（n≥3）对离子的形成机制、离子与中性气体原子或分子碰撞过程等问题的研究创造了更好的条件。