一种新型光栏直场加速管

文章通过对静电加速器加速管的场形计算和粒子轨迹计算，提出了有效地抑制次级电子的“Ｕ”型光栏直场加速管，经过加速器中高压试验和γ射线能谱测量，证实了“Ｕ”光栏直场加速管所预期的性能。     

高梯度加速管的设计

叙述了双间隙高梯度加速管的设计，介绍了加速管的主要部件的作用和结构，井扼要说明和讨论了加速管的试验结果。     

加速管场形计算

给出了一套计算加速管场形的实用程序——ＣＡＴＥＦ程序，它包括有限差分－超松弛迭代法求解加速管静电场和龙格－库塔法描述两部分。ＣＡＴＥＦ程序可以应用于加速管场形设计以及其他电子光学元件的设计；三维形式的ＣＡＴＥＦ适用于复杂电场的场形计算与设计。     

325 MHz高功率波导窗设计研究

为了使漂移管加速结构运行更加稳定，传输功率可更好地馈入质子直线加速器中，本文对漂移管加速结构的波导窗进行设计与研究。利用微波仿真软件CST对波导窗的结构进行计算，并通过改善匹配结构对射频参数进行分析及优化。通过仿真结果计算频率带宽、电场分布及功率损耗。最终对波导窗进行热分析，通过公式计算所需冷却水的流量。结果表明，该波导窗可应用于325 MHz加速结构中。     

9MeV行波电子直线加速器加速管的物理设计

海关大型货物在线检测用加速器采用４ＭＷ速调管作为微波功率源，保证加速管入口功率可达３．５ＭＷ、工作频率为２８５６ＭＨｚ；以行波方式加速电子，聚束器俘获效率大于８０％；加速管全长约２２０ｃｍ；电子能量设置９、６ＭｅＶ两档，对应的额定脉冲束流强度理论设计值分别为１７０和３００ｍＡ。本文给出了纵向粒子动力学、盘荷波导的尺寸及加速管的工作特性等方面的计算结果。     

17 高俘获效率电子直线加速器的设计研究

加速管是加速器设计的核心部分。常规设计加速器的俘获效率只能达50％左右，1/2的电子都损失在加速管内，丢失的电子会轰击加速管管壁，产生轫致辐射、腔体发热量增加、真空变坏等许多负面影响。采用等梯度加速结构，相速沿加速管呈线性增加，调整相速变化规律及加速管腔体的尺寸参数，设计的加速管最终俘获效率提高到90％以上，同时平均加速梯度没有因此降低，加速管总长度未增加。     

HI-13串列加速器加速管技术改造

HI-13串列加速器加速管技术改造已经完成。用1根243．8cm和7根223．5cm的加速管替代了已使用16年之久的8根182．9cm加速管。为配合新加速管的安装，对加速器的主体布局进行了调整，对加速器的死区结构、充电系统、电阻分压系统进行了改造，重新设计制作了加速管入口栅网透镜及供电和控制系统，研制了新的输电梯死区惰轮。改造后的加速器头部电压达15．07MV。     

9 MeV行波电子直线加速器加速管微波测试及调整

介绍了海关大型集装箱在线检测用加速器的核心部件９ＭｅＶ行波电子直线加速器加速管的微波测试及调整，并详细描述了加速管微波调谐、加速管与矩形波匹配以及加速管整管场分布及总衰减量的测量，给出了加速管微波测试及调整的结果，结果表明微波调度满足物理设计的要求。     

X波段2MeV行波电子直线加速管的物理设计

在模拟计算程序LINE-ACC/PC基础上，结合单一搜索方法和非线性最小二乘算法编程，实现一个X波段2MeV行波加速管的物理设计。应用此方法可以有效缩短加速管的优化设计时间。文章给出的优化计算可应用于一类常相速周期结构的加速管设计。文章同时给出了纵向粒子动力学、盘荷波导的几何尺寸及加速管的工作特性等方面的计算结果。     

NYZ—18医用加速管的焊接

叙述ＮＹＺ－１８医用加速管接的一系列技术要点。根据焊接设备特点和工艺要求，确定加速管分为几段焊接；段和段之间的对接焊缝尽可能选择在观察窗附近，以便于观察焊料熔化状态；还要远离氢炉温度偏低区域，避免焊料不完全熔化，强调装配过程中焊接面相互之间要良好接触；吊装时尺可能使焊接面与中垂线相互垂直，减少环，片之间的有和位移，保证焊缝的气密性，短段和整根加速管入炉前，焊接后都必须检查直线度，及时校正。     

400 kV强流中子发生器的物理设计

对400 kV强流中子发生器进行了物理设计。采用Poisson/Superfish软件对中子发生器高压电极和加速管的电场分布进行了模拟,结果显示,各关键区域的空间电场最大值远低于击穿电场限值。以强流束旁轴包络方程为基本模型,发展了强流束传输系统束包络的计算机模拟程序IONB1.0,模拟了中子发生器传输系统中40 mA的D束流包络。结果显示,设计方案中所采取的两间隙高梯度加速结构有较强的聚焦性能,能有效抵消强流束空间电荷效应造成的束流发散,加速管出口处的束包络半径约3 cm,由加速管出口处的空间电荷透镜和三重四极磁透镜组成的传输系统能将束流聚焦在约140 cm处的靶上,且束斑直径小于2 cm。     

Modification of a pulsed 14-MeV fast neutron generator to a medium-energy ion accelerator for TOF-RBS application

The first drift-tube neutron generator in Thailand, developed during 1980s under the support by the International Atomic Energy Agency (IAEA), was a 150 kV deuteron accelerator-based 14 MeV fast neutron generator. The accelerator was featured by a nanosecond pulsing system consisting of a beam chopper in combination with a beam buncher. Following the rapid development of ion beam technology and increasing needs for materials applications in the laboratory, the accelerator has been upgraded and modified to a large extent into a medium-energy ion-accelerator for time-of-flight Rutherford backscattering spectrometry (TOF-RBS) applications. The modification of the accelerator included the changing of the ion source, the accelerating tube and the mass-analyzing magnet, the upgrading of the pulsing system, and the installation of a TOF-RBS detecting system. The new accelerator is capable of supplying a 400-keV He-ion beam with ns-pulses for nano-layered materials analysis. This paper provides technical details of the modification.     

强流氘束引出系统与加速管束流匹配的研究

为增加传输通过加速管的束流强度，提高中子发生器的中子产额，采用Particle-in-cell(PIC)程序模拟研究了入射束强度在10～150 mA范围内，不同初始参数条件下D⁺₁束在加速管中的传输状态。结果表明，当入射束在加速管入口处的归一化发射度取0.25 πcm•mrad，Courant-Snyder参数α=-4、β=60 cm/rad时，50～100 mA D⁺₁束与加速管匹配良好。根据匹配参数，对双等离子体离子源的引出系统进行了优化，结果显示，在引出系统与加速管之间放置两个螺线管透镜和1个光阑，能有效去除D⁺₂、D⁺₃离子，实现100 mA D⁺₁束顺利传输通过加速管的目的。     

Lie代数方法及其在静电加速管像差分析中的应用--三级近似

用Lie代数方法分析了相对论脉冲束在静电加速管中的传输,得到其三级近似轨迹。根据需要还可以扩展到更高级近似。在分析中,把加速管看成由人口膜片、均匀场加速区和出口膜片三个单元组成;为了便于描述粒子在加速管中的轨迹,把加速管也分成若干段,在每个小区间上施加Lie变换。     

Computer investigation of ion beam optics for a Freeman type ion source system

The present work investigates the computer analysis of the ion beam properties produced by a Freeman type system. The extraction for such system is composed of four electrodes that permit to keep a fixed output energy by means of two accelerating gaps and one decelerating gap. The latter allows reducing the beam divergence angle. The combination of the acceleration/deceleration sections provides to keep a low beam emittance at the source outlet. The simulation of single charged argon ion trajectories for a plasma concave of curvature 4 mm was first studied with and without space charge effect using acceleration/deceleration extraction system with the aid of the SIMION computer program. The voltage applied to the accelerating electrode was optimized to accomplish the suitable ion trajectories without hitting the extraction electrode. Then, two additional studies were performed: the influence of the acceleration voltage and extraction voltage on the beam emittance and beam diameter; and the effect of the extraction gap width (distance between the plasma emission surface and the acceleration electrode) on the shape of the ion beam envelope and the position of the ion beam waist. Last, the influence of the space charge on the ion beam envelope was also investigated.     

Focused electron beam transport through a long narrow metal tube at elevated pressures in the forevacuum range

We present here our investigations of the features of focused electron beam transport in free space at elevated pressures of a few pascals.We have explored the effect of the beam accelerating voltage,operating gas pressure,and magnetic focusing upon the trajectory of beam electrons in the crossover region,in particular on the beam convergence and divergence angles.It is shown that for the forevacuum pressure range of 2-5 Pa explored,a distinctive feature of the propagation of a focused electron ...     

Optimizing the geometry of a negative ion sputter source

In order to avoid isotope fractionating effects due to slight fluctuations in the position, direction or divergence of the emerging beam, the emittance of an AMS ion source has to be lower than the acceptance of the following beam handling system. The emittance of a negative ion sputter source is determined by the energy spread of the sputtered ions and by its extraction geometry. For various configurations of the latter, we have calculated particle trajectories. Greatly reduced aberrations are attained if the electric field close to the emitting surface is nearly uniform and only weakly focussing and if the acceleration takes place in at least two lens sections. The single acceleration gap of our Hortig-type ion source [1] has therefore been replaced by a two-stage accelerating lens. Further, the curvature of the field at the surface of the sputter target is controlled by an additional electrode.     

扇聚焦等时性回旋加速器性能的改进和提高

安装了ＥＣＲ离子源及其外注入系统后，增加了离子种类、提高了束流强度。扇聚焦等时性回旋加速器（ＳＦＣ）主要工作点分布于三次谐波加速区域，为了匹配外注入系统，仔细地研究了中心区，重新设计加工了Ｄ盒及假Ｄ。为了改进ＳＦＣ性能，提高运行效率，同时进行了其它改进工作。介绍了改进后的ＳＦＣ的调束工作。     

Hot Cathode’s Working Voltage Impacts on the Operation of High Current Ion Source

High power ion source is one of the important parts of the neutral beam injection. It produces high energy beam by extracting and accelerating ions from its arc chamber. The hot cathode (filaments) in the arc chamber of the ion source operates in two modes. Operation mode of the cathode has great effect on the stable operation of the ion source. Based on the theory of hot cathode and experimental results, this paper presents the operation results (beam current, arc efficiency) of an ion source with various cathode temperatures (controlled by voltage applied to the cathode).     

750kV大气型高梯度加速管

设计和建造了一根750 kV大气型高梯度加速管。采用钛合金电极组成的两隙准均匀场,平均加速梯度为30 kV/cm。脉冲质子束50—200 mA可以顺利加速通过此加速管。最后讨论了真空清洁度对退锻率的影响。