中子发生器的纳秒脉冲聚束系统

为了用飞行时间法精确测量中子能谱,从俄罗斯Efremov电物理所引进了一台纳秒脉冲中子发生器。该中子发生器采用聚束系统产生纳秒脉冲束流,其中的纳秒脉冲信号源、高频聚束电源、负反馈调节系统等关键设备都是自主研制的。采用双扫描技术解决了聚束电源电压过高的问题,采用负反馈技术使纳秒脉冲聚束系统长期稳定工作。为了测量纳秒脉冲束流,研制了快脉冲同轴靶测量装置,测得中子发生器的离子束流脉冲半高全宽为1.5 ns,脉冲重复频率为1kHz-4MHz,束斑直径为10 mm。由于采用了电子回旋共振离子源(Electron Cyclotron Resonance,ECR),所以该中子发生器具有发射度小、能散小、无灯丝、可长时间连续工作的优点,是中子物理研究的良好实验平台。     

ECR离子源实验台的研制

介绍了ECR离子源实验台的工作原理、基本结构和研制过程。作为实验和测试平台,ECR离子源实验台可以很方便的调整离子源各参数,在靶上得到好的束流品质。通过对部件的改进和调试,解决了束流较小的问题,使ECR离子源工作在最佳状态。上述结果可用于中子发生器的运行调试。因此,ECR离子源实验台是强中子发生器所必需的实验设备。与国内外的ECR离子源相比,ECR离子源实验台主要着眼于中子发生器的模拟实验,在结构上强调小型化、实验平台化,在功能上要求能够在线测量许多重要参数。测量结果表明,ECR离子源实验台技术指标达到设计要求。     

永磁强流ECR离子源

文章介绍一台2.45 GHz永磁强流ECR离子源,其直径为10 cm,长10 cm,重量不足5 kg,可工作在直流模式和脉冲模式.脉冲模式引出的氢离子束峰值流强大于100 mA,束流密度达到500 mA/cm2;直流模式引出束流达到60 mA,束流密度为300 mA/cm2.两种模式的质子比均达到80%.     

小型移动式中子发生器

把从国外引进的高压终端与自行研制的脉冲系统等结合在一起,建成了一台小型移动式中子发生器。该中子发生器的长度是2 500 mm,重量小于1 t,可以方便地移动到所需要的实验场合。它主要由高频离子源、加速管、高压发生器、聚焦装置、供气系统、微秒脉冲系统、控制系统、真空系统和实验靶室组成。它能产生150μA的直流氘离子束和宽度为10～100μs,频率分别为10 Hz,1 000 Hz,10 000 Hz的脉冲氘离子束。D-T中子产额可达1.5×10~(10)s~(-1)。文章主要介绍了小型移动式中子发生器主要部件的工作原理和结构。     

高产额中子发生器研制

本文介绍了用于安检辐射成像的高产额中子管及中子发生器装置的主要性能指标和研发设计过程。中子管离子源采用冷阴极潘宁离子源,在引出阴极加磁钢,提高引出离子浓度。离子光学系统采用单电极加速结构,靶端通过外加电阻产生抑制电压,减小靶流,提高中子管工作稳定性。对中子管离子源和靶端通过散热结构设计和利用变压器油进行散热,效果良好。通过对中子管的各项性能参数进行测试,离子流可达50 mA以上,引出束流接近1 mA,中子产额达1.1×10¹⁰s^-1。研发的高产额中子管及发生器装置具有产额高、工作稳定、安全便携等优点,达到了设计目的。     

用于中子发生器的小型ECR离子源设计

介绍了用于中子发生器的小型ECR(电子回旋共振)离子源的工作原理、基本结构和预期技术指标。叙述了该系统的设计过程、关键技术和创新点。     

脉冲离子束作用下的靶温度场-应力场耦合分析

靶温对无冷却装置的密封式中子发生器的靶寿命有重要影响。为对脉冲离子束作用下靶进行热-力耦合分析,采用以时-空二维高斯轴对称分布的功率密度为热源的间接耦合的有限元方法,获得了不同脉冲离子束工作状态下的靶温度场和应力场有限元分析结果。结合密封式中子发生器的靶温要求和热应力引起的靶膜热-力破坏效应,优化了密封式中子发生器中的脉冲离子束工作参数。     

中子管用PIG负氢离子源及其束流引出实验研究

PIG离子源用于中子管引出正离子,但在使用过程中存在一定问题,如单原子离子比低、靶材料溅射严重及功耗大等。为解决这些问题,提高中子管的寿命和稳定性,本文设计一种中子管用PIG负氢离子源,并对其束流引出进行实验研究。分别测量了离子源的磁场、不同阴极材料及引出阴极离子发射孔径对引出负氢离子束流的影响。实验数据表明,该负氢离子源可用于制作性能指标良好的中子管。     

用于蓝姆移动型极化离子源的低能强流双等源

建立了用于蓝姆移动型极化离子源的双等源和低能引出聚焦系统，实验比较了等离子体出口孔径和聚焦电极之间的距离对引出束的影响，并调整了离子源的运行参数。离子束的质子比可达６０％以上，满足了极化离子源的工作要求。约有４ｍＡ低能氢离子束（５５０ｅＶ）或氘离子束（１１００ｅＶ）进入铯蒸汽电荷交换管道，在极化源上使用低能强流双等源后，可获得２００ｎＡ左右的极化质子（或氘核）束。     

CIAE强流ECR离子源研制

本文介绍了研制的一台强流ECR微波离子源,其能从7 mm直径的圆孔引出大于150 mA的氢离子束(75 keV),质子比达90%。该离子源采用独特的结构提高了离子源寿命。离子源在75 keV、110 mA束流条件下连续工作超过220 h,束流中断2次,不间断工作时间超过150 h。     

Monitoring the Electron-Orbit Shift and Radiation Beams

A system for performing television monitoring of the position of the synchrotron radiation beam is discussed. The results of measurements of the stability of the beam position in several user channels are presented. It is shown that further work is needed to determine and eliminate the factors causing beam displacement. The results of measurements performed by different methods of the electron-beam dimensions in the accumulator are presented.     

High Current DC Ion Beams

The beam systems which have been developed for use in high energy injection experiments in thermonuclear research are described. An attempt is made to compare the quality of these beams (not the relative merit of the injection systems). Problems peculiar to the production of intense dc beams are discussed.     

Transport of Intense Ion Beams

The possibility of using intense bursts of heavy ions to initiate an inertially confined fusion reaction has stimulated interest in the transport of intense unneutralized heavy ion beams by quadrupole or solenoid systems. We have examined this problem in somne detail, using numerical integration of the coupled envelope equations for the quadrupole case. The general relations which emerge are used to develop examples of high energy transport systems and as a basis for discussing the limitations imposed by a transport system on achievable intensities for initial acceleration.     

Space Charge De-Bunching in Charged-Particle Beams

One of the factors influencing the properties of a pulsed beam is the growth of the charge bunches due to space charge forces. The growth along the direction of motion of the bunch degrades the time-structure of the pulsed beam and the growth transverse to the direction of motion de-focuses the beam. Although the space charge effect is only important at high current densities, it must be considered a limiting factor in any pulsed beam system. A general method of obtaining the field in the bunch to second order in v/c was developed. From this the motion of charges in the bunch was obtained by numerical integration for the case of a Gaussian distribution of space charge under the assumption that the charge distribution remains Gaussian. Solutions are presented in a dimensionless, graphical form which can easily be scaled for a particular problem.     

Collective Acceleration with Intense Electron Beams

Collective acceleration methods that employ an intense relativistic electron beam (IREB) are discussed. A brief history and a classification of collective acceleration methods are given. Methods examined include IREB injection into neutral gas; IREB injection into vacuum; plasma-filled IREB diodes; and vacuum-filled IREB diodes. Accelerating fields of order 106 V/cm have been observed experimentally. The collective acceleration processes for IREB injection into neutral gas and vacuum are discussed. It is noted that the collective acceleration processes for IREB diodes have not been elucidated yet. A summary of present collective ion acceleration research areas that involve IREB's is given.     

Inertial Confinement Fusion Energy with Particle Beams

This paper introduces the concepts associated with inertial confinement fusion (ICF) energy production, and outlines particle beam technologies of interest for ICF applications with emphasis on ion beams. Progress in obtaining larger thermonuclear neutron yields from laser fusion pellets and the constantly improved understanding of these experiments, makes the application of particle beam techniques to this area look increasingly promising. The reason for this is that lasers suitable for demonstrating the feasibility of igniting fusion pellets are becoming available, but lasers offering the requisite properties for fusion power plant application have apparently not been identified. Accelerator designers can suggest several promising avenues to produce a driver for a power plant. To place some perspective on the issues, a brief review will be given of ICF target requirements. This will be followed by a brief historical view of heavy ion fusion, a synopsis of the various accelerator approaches and associated problems that have been recognized, and a summary of power plant considerations.     

裂纹梁非线性响应分析

基于Lagrange方程建立含裂纹两端铰支空心梁在简谐激励作用下的运动方程。运动方程考虑了几何非线性以及裂纹的张开闭合状态的交替变化。采用数值算法研究含裂纹空心梁在简谐激励作用下的超谐共振、次谐共振,所得结论与已有文献的结论一致。在较大简谐激励幅值条件下,深入探讨几何非线性对含呼吸裂纹梁响应的影响,为空心梁类结构的裂纹识别提供有益参考。     

用无本影装置测定中子照相射线束的准直比

本文介绍了一种用无本影装置测定中子照相射线束准直比的方法，用这种技术通过对无本影装置影像的分析就可以确定中子束的准直比，而不需要测量和计算准直器系统的有关物理量。