高梯度加速管的束流传输

对不同能量、不同质量数、不同初始条件的入射束和有无空间电荷效应的离子束流在高梯度加速管中的传输进行了计算，并讨论了一些影响加速管聚焦作用的主要因素，计算结果与实际情况相符。     

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。     

特大直径加速管的封接

高能物理所750kV预注入器是30MeV质子直线加速器的前级加速器。它采用大气型高梯度加速管,已成功地加速50—200mA脉冲质子束,从1982年以来一直运行正常。 大气型加速管的结构比高气压型简单,而且维修方便。但由于高梯度加速场要求加速电极伸入管内,形成很强的径向电场,加速管直径必然很大(图1)。与国外同类型加速管相比较,西欧CERN加速管瓷环内径500mm,我们的加速管由于安装在加速电极内部的离子源和     

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。     

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。     

加速管锻炼的光电监测

静电型加速器特别是大型串列式加速器的核心部件是昂贵的加速管。加速管的耐压能力在达到其额定电压之前要经历一个锻炼过程,正确地控制锻炼过程的进度是确保加速管安全迅速地达到额定电压的关键。目前国内静电型加速器加速管锻炼时用的监测方法主要是监测X射线的强度和加速管内真空度的变化,这些方法在直场加速管的情况下是有效的,但在斜场加速管的情况下,由图1可见加速管内能够获得最大能量的粒子是由A点出发到C点终止的粒子,其他二次粒子均受到邻近电极的拦截。若加速管电极在倾斜方向的孔径为d,电极之间的轴向距离为P,轴向电压梯度为E,电极倾角为θ,则二次粒子能够     

低功率加速管冷却系统的数值仿真设计

借助数值模拟的方法对低功率加速管的温度场进行模拟分析,为其设计出合理的冷却系统.分析数据显示该冷却系统的主要作用不是冷却而是使温度均匀化和降低环境影响,这可为类似装置冷却系统的设计提供参考.     

一种抑制辐射闭锁的新方法

从体硅CMOS器件的闭锁效应入手,提出了抑制闭锁的一种新方法-伪闭锁路径法.详细探讨了伪闭锁路径的设计方法后,还提供了一个设计实例,给出了计算机仿真结果和实验验证结果.伪闭锁路径法能够较好抑制体硅CMOS器件的永久闭锁问题,但不能避免辐射引起的剂量率扰动.     

可批量化生产的行波加速管的设计

盘荷波导行波电子直线加速器在医疗、工业辐照及安检等领域均有广泛的应用,加速器核心部件加速管的工程造价及生产效率对其工业推广具有重要的影响。为降低加速管加工成本、缩短加工周期,在盘荷波导的基础上改进了加速腔结构,发展了内阶梯加速腔。利用三维电磁场模拟软件CST(Computer Simulation Technology)计算了这种腔型的微波参数,同时对其结构进行优化。结果表明,内阶梯加速腔结构具有和盘荷波导一致的微波参数,而且能够实现精确调频。结合冷挤压工艺对内阶梯加速腔进行加工,解决了目前加速管制造所面临的工程困难,使得加速管批量化生产成为可能。     

200 kV非线性强流加速管的离子光学设计

一、问题的提出研制强流离子注入机的关键,除了要有强流离子源外,主要是克服束流传输过程中的空间电荷效应问题。为此,我们研究非线性强流加速管,来克服强流束在加速管中的空间电荷效应。     

800kV高压传输装置的电场数值计算

介绍了800kV高压传输装置的组成和结构安排；对在SF6绝缘气体环境中的电缆终端进行了电场数值计算，并对计算结果进行了分析；最后得出结论，电缆终端的场强设计是可靠的。     

A multi-exciton model for the electronic sputtering of oxides

Three models are examined for the electronic sputtering by high energy heavy ions. It is found that the charged fraction of the sputtered particles is small (less than 10% in this study) and hence, Coulomb explosion model is unsound. According to the thermal spike model, rapid thermal quenching of the melted zone is anticipated, implying amorphisation of SiO₂ single crystal (c-SiO₂). X-ray diffraction results indicate no amorphisation of c-SiO₂, suggesting no melting. Moreover, the electronic sputtering yields of both c-SiO₂ and amorphous-SiO₂ (a-SiO₂) have been found to be the same. With these results and thermal properties of both c-SiO₂ and a-SiO₂, thermal spike model is examined further and appears to be unfavorable. A multi-exciton model is suggested for the electronic sputtering.     

强流中子管微波离子源微波吸收效率的实验研究

强流中子管微波离子源实验系统已建成。给出磁场模式设计结果,通过实验确定微波吸收效率与磁场分布及气压的关系,其中微波输入功率300-500W。微波引入窗处的磁场为0.095T时,微波吸收效率都在90%以上,最高达到100%。     

一种加偏压减小磁场对样品电流信号影响的方法

在用样品电流法测量X射线磁性圆二色谱中,外磁场的存在严重降低了样品电流信号.针对合肥NSRL软X射线磁性圆二色实验站内置式可旋转磁铁设计并安装一个紧靠磁极的高压金网,来增强磁场下的样品电流信号.发现不同磁场下随偏压升高,样品电流信号迅速增强并趋于饱和;磁场越强,达到饱和需要的偏压越高;比较相同磁场和偏压下均匀氧化的Al箔和CoFe薄膜正反磁场下的吸收谱,发现加磁场和偏压引入的系统误差仅相当于Co的圆二色值的2.17%;表明用这种方法进行X射线磁性圆二色谱的测量是可行的.     

Study of a 105 GHz short-pulse dummy load for the electron cyclotron resonance heating system with the quasi-optical method

The accurate power measurement is important for an ECRH system in tokamak. The dummy load is designed and developed for the measurement of the millimeter wave power. This work analyzes the dummy load based on the quasi-optical method and the ray tracing method. The reflectivity and thermal deposition of the dummy load have been considered to ensure the safety of the entire system. High-power tests have been carried out at a 105 GHz/500 kW ECRH system. The results of the tests indicate that the designed dummy load is stable and valid.     

Development of signal analysis method for the motional Stark effect diagnostic on EAST

A pilot single-channel Motional Stark Effect (MSE) diagnostic has been developed on EAST since 2015.The dual photo-elastic modulators (PEM) were employed to encode the polarization angle into a time-varying signal.The pitch angle was related to the ratio of modulation amplitude at the second harmonic frequency.A digital harmonic analyzer (DHA) technique was developed for extracting the second harmonic amplitude.The results were validated with a hardware phase lock-in amplifier,and is also consistent with the software dual phase-locking algorithm.     

A cycle configuration for large-scale helium refrigerator for fusion devices towards complete mitigation of the effects of pulsed heat load

Large-scale helium refrigerators in fusion devices work in pulsed heat load condition. The immediate effect of pulsed heat load is mass flow rate fluctuation at the low pressure return stream to the cold-box of the refrigerator. As a result, thermodynamic properties of all the intermediate state points of the cold-box vary widely and may go beyond operating limits. Therefore, for continuous operation, the refrigerators need modification in cycle configuration in order to mitigate the effects of pulsed heat load generated out of the operation of the fusion devices. A number of mitigation techniques exist and none of them is capable of mitigating the mass flow rate fluctuation completely. However, combinations of two or more methods have been found to be effective in mitigation of the effects of pulsed load to the maximum possible extent. In this paper, a cold-end configuration has been proposed that is constituted of combination of different mitigation schemes proposed in previous works. Dynamic simulations are performed to predict the performance of the modified cycle configuration and for validation of the concept towards achievement of complete mitigation. Results of the work have revealed that through the proposed cold-end configuration, almost complete mitigation can be obtained.     

大型汽轮发电机组轴系动平衡效果及整机振动水平综合评价方法探讨

大型汽轮发电机组振动监测数据测点一般多达四五十个,对每一个数据单独评价往往缺乏整体概念。提出一种综合评价大型汽轮发电机组轴系动平衡效果及整体振动水平的简洁方法,把表征任意时刻机组振动状态的众多振动数据集约为一个综合性指标参数。同时还对有关术语定义、物理概念以及案例分析等作了全面论述。     

A closed-form solution for the two-dimensional transport equation by the LTSN nodal method in the energy range of Compton effect

In the present work we report on a closed-form solution for the two-dimensional Compton transport equation by the LTS_N nodal method in the energy range of Compton effect. The solution is determined using the LTS_N nodal approach for homogeneous and heterogeneous rectangular domains, assuming the Klein–Nishina scattering kernel and a multi-group model. The solution is obtained by two one-dimensional S_N equation systems resulting from integrating out one of the orthogonal variables of the S_N equations in the rectangular domain. The leakage angular fluxes are approximated by exponential forms, which allows to determine a closed-form solution for the photons transport equation. The angular flux and the parameters of the medium are used for the calculation of the absorbed energy in rectangular domains with different dimensions and compositions. In this study, only the absorbed energy by Compton effect is considered. We present numerical simulations and comparisons with results obtained by using the simulation platform GEANT4 (version 9.1) with its low energy libraries.