脉冲离子束轰击靶的热效应数值模拟

分析了脉冲离子轰击靶膜和衬底的热效应,在能量较低的情形下,离子轰击处理为靶膜表面热流输入。采用有限元程序,对能量为600keV、束流为12mA的不同束斑半径的脉冲离子流轰击Cu基Ti靶的热传导进行了数值计算,得到了热传导清晰物理图象。     

强流离子束传输系统束包络的计算机数值模拟

以强流离子束包络方程为基本模型，提出了微元近似数值计算强流离子束包络的方法。编写的计算机模拟设计强流束传输系统的程序包含高压裂加速器常用的电元件和磁元件。     

Ion beam propagation and focusing

Inertial confinement fusion with ion beams requires the efficient delivery of high energy (1 MJ), high power (100 TW) ion beams to a small fusion target. The propagation and focusing of such beams is the subject of this paper. Fundamental constraints on ion beam propagation and focusing are discussed, and ion beam propagation modes are categorized. For light ion fusion (LIF), large currents (2–33 MA) of moderate energy (3–50 MeV) ions of low atomic number (1A12) must be directed to a target of radius 1 cm. The development of pulsed power ion diodes for LIF is discussed, and the necessity for virtually complete charge neutralization during transport and focusing is emphasized. Fornear-term LIF experiments, the goal is to produce pellet ignition without the standoff needed for the ultimate reactor application. Ion diodes for use on Sandia National Laboratories Particle Beam Fusion Accelerators PBFA-I (2–4 MV, 1 MJ, 30 TW, operational) and PBFA-II (2–16 MV, 3.5 MJ, 100 TW, scheduled for operation in 1985) are discussed. Ion beam transport from these diodes to the pellet is examined in reference to the power brightness . While values of =2–5 TW/cm²/sr have been achieved to date, a value of 100 TW/cm²/sr is needed for breakeven. Research is now directed toward increasing , and means already exist (e.g., scaling to higher voltages, enhanced ion diode current densities, and bunching), which indicate that the required goal should be attainable. Forfar-term LIF applications, the goal is to produce net energy gain with standoff suitable for a reactor. This may be achieved by ion beam transport in preformed, current-carrying plasma channels. Channel transport research is discussed, including experiments with wire-initiated, wall-initiated, and laser-initiated discharge channels, all of which have demonstrated transport with high efficiency (50–100%). Alternate approaches to LIF are also discussed, including comoving electron beam schemes and a neutralized beam scheme. For heavy ion fusion (HIF), moderate currents (10 kA) of high energy (10 GeV) ions of high atomic number (A200) must be directed to a target of radius 0.3 cm. Conventional accelerator drivers for HIF are noted. For a baseline HIF reactor system, the optimum transport mode for low charge state beams is ballistic transport in near vacuum (10^–4–10^–3 Torr lithium), although a host of other possibilities exists. Development of transport modes suitable for higher charge state HIF beams may ultimately result in more economical HIF accelerator schemes. Alternate approaches to HIF are also discussed which involve collective effects accelerators. The status of the various ion beam transport and focusing modes for LIF and HIF are summarized, and the directions of future research are indicated.     

Study on Integral Expression in Measurement of Average Ion Velocity by Multi-Grid Probe

In order to improve the interference rejection performance in the measurement of average ion velocity by multi-grid probe, an integral expression is proposed. The integral expression, differing from other expressions for probe measurement, avoids the differential operation on the I-V characteristics of multi-grid probe measurement; and by this method, the ion average velocity can be figured out directly by the I-V characteristics of multi-grid probe measurement.     

BRISOL谱仪关键技术研究

HI-13串列加速器升级工程在线同位素分离器（BRISOL）需对同质异位素进行分辨,谱仪设计质量分辨率为20 000,是很高的技术指标,对离子源、高压、分析磁铁、四极透镜等设备均有很大的挑战。本文详细介绍了BRISOL谱仪关键技术及其测试结果。能散对谱仪的质量分辨率影响较大,BRISOL谱仪设计采用异能大小铁结构消除能量色散。离子源采用表面离子源,并采用三电极引出系统,中间电极电压可调用以优化束流品质,优化后离子束RMS发射度好于3.8 πmm•mrad。分析磁铁采用表面线圈进行磁场垫补,垫补后积分场均匀性好于3.5×10^-5。为修正像差,大分析磁铁安装了β线圈和γ线圈,同时,在分析磁铁前后共设置了4台电六极透镜。     

简单可靠的双探针束流剖面仪

本文介绍了步进电机驱动的双探针束流剖面仪。它可以测量强直流离子束中的束流分布。其扫描速度和步长均可调节,并同时记录在X-Y记录仪上。由于采用了步进电机,使得定位准确,重复性好。本文还对探针测量方法作了理论分析,并给出选取探针直径的原则。     

A New Three-Dimensional Code for Simulation of Ion Beam Extraction： Ion Optics Simulator

A new thee-dimensional code, ion optics simulator （IOS）, to simulate ion beam extraction is developed in visual C＋＋ language. The theoretical model, the flowchart of code, and the results of calculation as an example are presented.     

双维位置灵敏探测器性能测试

对用于放射性次级束测量的大面积双维位置灵敏探测器 （PSD）的性能进行了测试。通过选择实验中电子线路的脉冲成形时间 ,并改进数据处理方法 ,即主放大器的成形时间常数要大于6 μs,而位置路的时间常数约为 0 .5— 1μs ,且在位置公式中使用能量信号作为分母 ,测试得到了较好的位置分辨和能量分辨及线性。结果表明 ,这一类型的PSD探测器可以用于低能放射性束流的测量     

A Monte Carlo study of surface sputtering by dual and rotated ion beams

Several, recently proposed methods of surface manufacturing based on ion beam sputtering, which involve dual beam setups, sequential application of ion beams from different directions, or sample rotation, are studied with the method of kinetic Monte Carlo simulation of ion-beam erosion and surface diffusion. In this work, we only consider erosion dominated situations. The results are discussed by comparing them to a number of theoretical propositions and to experimental findings. Two ion-beams aligned opposite to each other produce stationary, symmetric ripples. Two ion beams crossing at right angle will produce square patterns only, if they are exactly balanced. In all other cases of crossed beams, ripple patterns are created, and their orientations are shown to be predictable from linear continuum theory. In sequential ion-beam sputtering we find a very rapid destruction of structures created from the previous beam direction after a rotation step, which leads to a transient decrease of overall roughness. Superpositions of patterns from several rotation steps are difficult to obtain, as they exist only in very short time windows. In setups with a single beam directed towards a rotating sample, we find a non-monotonic dependence of roughness on rotation frequency, with a very pronounced minimum appearing at the frequency scale set by the relaxation of prestructures observed in sequential ion-beam setups. Furthermore we find that the logarithm of the height of structures decreases proportional to the inverse frequency.     

快中子堆主壳顶盖环形空间自然对流的实验研究与数值模拟

快堆顶盖存在一些大小不同的环形空间,这些空间是由穿过顶盖结构的一次泵及热交换器构成的,并使环形空间内的氩气产生自然对流。用有机玻璃建造的实验台,模拟快中子堆主壳顶盖竖直环形空间,进行自然对流实验研究。同时,采用LVEL零方程湍流模型对自然对流进行了数值模拟,所获结果与实验数据基本吻合,表明该模型比常用的kε模型所得出的流型与文献中的和该实验的观测结果更加相符,也能够更加准确地预测环形空间内的温度场与速度场。     

核电厂管线中的温度振荡现象研究

在核电厂中,如何更好地了解和预防由于温度振荡而导致的管线热疲劳,对于确保核电厂的安全和可靠运行具有重要意义。本文以核电厂安注系统某支管为研究对象,运用计算流体力学软件,结合二次开发,采用修正的k-ε模型,模拟了阀门渗漏冷水进入含有高温水的支管后所发生的温度振荡现象,并与实验测量进行了对比。数值模拟的结果和实验基本吻合,并全面地反映了整个管线中的温度振荡现象,为更好地监控管线热疲劳提供了参考依据。     

321型束流剖面监测仪在离子束技术中的应用

束流剖面监测仪是监测带电粒子束在传输过程中状态变化的一种装置。该装置的叶片式探针（以下简称探针）安装在粒子加速器、同位素分离器和离子注入机等监测位置上并由它把截获的信号显示在示波器屏上便可观察到沿束横截面束流密度分布曲线（以下简称束形）。通过束形变化我们可定性地判断束流强度、束流品质和它在束管道中的相对位置等。因此,它在国外各种类型的粒子加速器上广为使用。     

高能碰撞中的多重数分布与动力学涨落

通过多重数分布研究EMU0 1国际实验组中高能重核束流与核乳胶相互作用中的动力学起伏的规律。引入多重数分布动力学因子dq 及其比值Dq 两个物理量来定量量度动力学涨落 ,得到了Dq 与D2 的幂次标度律 ,并且给出标度律中指数与 q - 1的标度关系 ,所得出的标度指数γ的值在各种碰撞体系中大致相同     

20kV射频堆积腔的物理设计

分析了重离子束的射频堆积过程。在此基础上,根据兰州重离子加速器冷却储存环（HIRFL-CSR）内束流流强为10     

Balance of Liquid-phase Turbulence Kinetic Energy Equation for Bubble-train Flow

In this paper the investigation of bubble-induced turbulence using direct numerical simulation (DNS) of bubbly two-phase flow is reported. DNS computations are performed for a bubble-driven liquid motion induced by a regular train of ellipsoidal bubbles rising through an initially stagnant liquid within a plane vertical channel. DNS data are used to evaluate balance terms in the balance equation for the liquid phase turbulence kinetic energy. The evaluation comprises single-phase-like terms (diffusion, dissipation and production) as well as the interfacial term. Special emphasis is placed on the procedure for evaluation of interfacial quantities. Quantitative analysis of the balance equation for the liquid phase turbulence kinetic energy shows the importance of the interfacial term which is the only source term. The DNS results are further used to validate closure assumptions employed in modelling of the liquid phase turbulence kinetic energy transport in gas-liquid bubbly flows. In this context, the performance of respective closure relations in the transport equation for liquid turbulence kinetic energy within the two-phase k—epsilon and the two-phase k—l model is evaluated.     

基于静电探针诊断下离子源调制放电

介绍了在静电探针测量下,离子源调制放电闭环控制系统设计要求,讨论了该系统的硬件设计、软件设计及其工作原理,给出了部分实验结果.系统成功地应用于实验并获得初步实验结果,为以后中性束注入开展相关物理实验提供可靠保障.     

叠层塑料闪烁探测器望远镜

描述了由１ｍｍ厚的快塑料闪烁体ＮＥ１０２Ａ和１００ｍｍ厚的慢塑料闪烁体ＮＥ１１５组成的叠层闪烁探测器望远镜（Ｐｈｏｓｗｉｃｈ）。光电倍增管阳极信号用传统的快慢门－ＱＤＣ方法处理,对Ｚ≤２０碎片得到了较好的粒子鉴别,元素分辨Ｚ／ΔＺ～４５。     

尼尔逊离子源重离子束流的发射度

尼尔逊离子源已广泛地应用于重离子加速器、同位素分离器及研究用离子注入机。用于C-600离子注入机的尼尔逊离子源,目前已获得达100µA的三十余种重离子束,其中有近二十种固体元素。