荷能带电粒子在碳纳米管绳内的沟道效应

碳纳米管绳是近年来才产生的超晶格结构的大单晶体。荷能带电粒子在碳纳米管绳内的沟道效应显示出大的沟道直径和微弱的退沟道因子。在粒子束物理的领域中，碳纳米管绳沟道的最迷人应用是：与在高梯度加速场里粒子加速的可能性相联系；与建造TeV对撞机的可能性相联系。本文介绍了这类应用研究的进展。     

X射线在碳纳米管(绳)和Fullerites晶体内的传输

近年来发展起来的新毛细管光学聚焦元件由许多根弯曲的多層壁碳纳米管组成,能被用来产生高强度的nm级X射线微束.作为软X射线布拉格(Bragg)衍射传输的新元件,单層壁碳纳米管绳(超晶格结构的晶体)和Fullerites(C60分子晶体)已经引起了世界范围内的研究兴趣.本文介绍这方面的研究进展.     

高能粒子的沟道效应和阻塞效应

近年来的实验事实表明,在GeV能区,沟道效应和阻塞效应仍然很好保持,而且,它们有可能在高能物理实验中得到一些有意义的应用。     

微传输矩阵及其在强流带电粒子束光学计算中的应用

本文提出了微传输矩阵的概念,讨论了它的基本性质,并将它应用于强流带电粒子束的光学计算。     

单晶硅面沟道效应的研究

采用静态的Molière面连续势并计及相邻各晶面的影响,计算了单晶硅<100>、<110>和<111>面沟道的半角宽度以及产额极小值,同1MeV质子对单晶硅面沟道实验测量结果进行了比较。理论分析和实验测量都表明,虽然<111>晶面有两种不同的面间距,但<111>面沟道只存在一个坑。     

GaAs中子嬗变掺杂热退火的沟道效应分析

中子嬗变掺杂是一种新掺杂方法,能将掺杂剂均匀分布引入晶体内。如GaAs在热中子作用下其同位素被激活为放射性核素,β衰变后变成稳定的Ge和Se,在此晶体作为施主杂质。辐照中晶格原子受到高能粒子的反冲,使晶格结构紊乱,经退火得到恢复后,杂质原子才能起载流子作用。将未掺杂的GaAs单晶在轻水堆中照射,冷却后的晶体按〈100〉定向切片,经抛光清洁处理后在氢气氛下进行等时(30分钟)不同温度400—800℃的热退火。利用1.5MeV     

沟道效应及某些应用的研究

本文介绍沟道-背散射分析的实验装置。用沟道-背散射方法进行了辐射损伤测定、表面组分分析、异质外延层的缺陷分析,得到了一些对半导体材料工艺、集成电路研制的有意义的结果。     

高能同步辐射光源低能束流输运线设计研究

高能同步辐射光源（HEPS）是计划在北京建造的发射度小于60 pm•rad的超低发射度光源。它由1台500 MeV直线加速器、1条500 MeV低能束流输运线、1台500 MeV～6 GeV的能量增强器、2条6 GeV的高能束流输运线、1台6 GeV的储存环以及同步辐射光束线和实验站组成。本文进行低能束流输运线的设计研究。低能束流输运线是连接直线加速器和增强器的束流传输线,在考虑建设布局限制的基础上,对两端的束流包络进行匹配,并将直线加速器产生的束流高效传输到增强器注入点。HEPS低能束流输运线设计时采用了功能分区的设计策略,设计有3个功能区,分别是消色散注入匹配区、光学参数匹配区、输出匹配区。为校正误差对束流的影响,HEPS低能束流输运线设置了8个BPM,水平和垂直各6块校正磁铁用于束流轨道校正,校正后的轨道满足束流传输要求。     

利用粒子辐照技术实现碳纳米管向金刚石的转变

采用低能氢等离子体和中能C^ 离子束辐照技术相结合的方法,实现了碳纳米管向金刚石纳米晶粒的转变,完成了一个从有序(碳纳米管)到无序(无定形碳纳米线)再到有序(金刚石纳米晶)的转变过程。利用透射电子显微镜(TEM)、选区电子衍射(SAD)和拉曼光谱(Raman)等研究了晶粒的微观结构,并对纳米金刚石晶粒的生成机理进行了初步探讨。     

低能高电荷态离子Uq+在金属Al(111)表面掠射产生沟道效应的计算机模拟

用自己编写的STARF程序,系统地研究了低能高电荷态离子U^q (g=10-40)在Al(111)晶面上掠射时,反射系数、反射离子的角分布等对于离子入射角、电荷态和能量的依赖关系;并探讨了高电荷态离子在金属表面产生沟道效应的条件。     

高能重离子碰撞中能量密度和粒子密度数值分析

分别用无穷级数展开方法和数值积分计算中的高斯-拉盖尔求积法对高能重离子碰撞中能量密度和粒子密度数值进行计算，并对结果及级数展开中的高次项和一次项的大小进行了比较。结果表明：高斯-拉盖尔方法可以作为一种实用的算法应用在高能重离子碰撞的计算中。     

粒子加速器的回顾与展望

在回顾 2 0世纪加速器能量提高和技术的发展的基础上 ,展望了粒子加速器向高能量前沿、高亮度前沿、实际应用以及新原理、新技术的发展。     

Channeling regimes in ion surface scattering

We report on surface channeling experiments of singly charged ions on single crystal surfaces of Pt(1 1 0) and Pd(1 1 0). Using a time-of-flight system installed in forward direction we analyze the energy distribution of the scattered projectiles. By variation of the primary energy and the angle of incidence we investigate effects of the perpendicular energy on the channeling features. The perpendicular energy is defined as E = E₀sin²ψ with ψ the angle of incidence. In combination with precise azimuthal rotations of the crystal, we are sensitive to axial channeling and obtain information about the limits of axial surface channeling. From a comparison with detailed trajectory calculations we find that axial channeling effects are most pronounced for a perpendicular energy between 5 and 20 eV. As a result, we obtain an exemplary channeling map for the interaction of nitrogen ions with the (1 × 2) reconstructed Pt(1 1 0) surface identifying different channeling regimes.     

Angular distributions of Diffracted Channeling Radiation from moderate energy axially channeled electrons in Si and LiF crystals

Numerical calculations of the Diffracted Channeling Radiation angular distributions from axially channeled electrons with relativistic factor γ = 20 in Si and LiF crystals are performed. The calculations are based on a newly developed effective quantum-mechanical calculations algorithm of the wave functions and electron energies at axial channeling in a crystal. The numerical results obtained exhibit some new features of the Diffracted Channeling Radiation from axially channeled electrons compared to that from planar channeled electrons, e.g. increase of the widths of peaks, which might be useful in future experiments on observation of Diffracted Channeling Radiation.     

CR39探测器的带电粒子能量响应研究

为在神光系列激光装置上开展惯性约束聚变(ICF)带电粒子诊断,通过0.7~10 MeV加速器质子源和241 Am放射性同位素α粒子源完成了CR39探测器的质子和α粒子能量响应实验研究,结合TRIM程序和半经验模型建立了CR39刻蚀动力学模拟程序,模拟分析了p、D、T和α粒子在正入射和斜入射条件下CR39的径迹形状与能量响应特征,对多种ICF带电粒子谱仪的CR39探测器单元的设计提出了优化方案。     

A Solution of a Material Balance Equation of Channeling Stage Model for a Simple Case of a Water Distillation Column

Xenon oscillations in large PWRs are well understood and there have been no operational problems remained. However, in order to suppress the oscillations effectively, optimal control strategy is preferable. Generally speaking in such optimality search based on the modern control theory, a large volume of transient core analyses is required. For example, three dimensional core calculations are inevitable for the analyses of radial oscillations. From this point of view, a very simple 3-D model is proposed, which is based on a reactor model of only four points. As in the actual reactor operation, the magnitude of xenon oscillations should be limited from the view point of safety, the model further assumes that the neutron leakage can be also small or even constant. It can explicitly use reactor parameters such as reactivity coefficients and control rod worth directly. The model is so simplified as described above that it can predict oscillation behavior in a very short calculation time even on a PC. However the prediction result is good. The validity of the model in comparison with measured data and the applications are discussed.     

Bursty Behaviour of Turbulent Particle and Energy Fluxes in Edge Plasma of HT-7 Tokamak

High time resolution measurements of the electrostatic fluctuations and the turbulent particle and energy fluxes have been performed with a Langmuir probe array in the edge plasma in HT-7 tokamak. Bursty behaviour was observed in the time resolved turbulent fluxes with positive skewness and large kurtosis. The contribution of the large sporadic bursts to the transport losses were estimated. The analysis shows that the turbulent fluxes have different behaviour in different frequency domains and the probability distribution functions （PDFs） of the particle and energy fluxes present two distinct scaling ranges. All these are essentially consistent with the predictions of the self-organized criticality （SOC） model, though further studies are needed.     

核辐射能量全沉积脉冲分析与MCNP粒子跟踪验证

本工作就在数字化核辐射脉冲处理中观测到的全能峰计数上的较大差异,并根据探测器的特性,利用MCNP中的粒子跟踪卡,对能量全沉积射线粒子进行跟踪模拟。结果表明：有一定数量的能量全沉积脉冲与上升沿堆积脉冲波形存在较大的相似。模拟给出了真正上升沿堆积脉冲的幅度分布谱图,为数字化上升沿堆积脉冲处理及全能峰脉冲计数校正提供了很好的参考。