共查询到13条相似文献,搜索用时 62 毫秒
1.
推导了静电引出通道的等效简阶振荡方程(轴向),给出了引出系统的一阶传输矩阵:分析了引出束初始发射度椭圆矩阵的确定方法;给出了束发射度计算结果,并与国外同类型加速器的实测作了比较。 相似文献
2.
采用双粒子模型,讨论了束流能散度和传输管道孔径变化对由第一个宏粒子产生的束流尾场的影响。并将所得的计算尾场效应的公式,变换成六维传输矩阵的形式,使之能用于束流传输系统的模拟计算。 相似文献
3.
4.
本文研究在环形流道热入口区以及壁面热流沿轴向变化的棒束流道中液金属钠的传热。首先求解在恒定的壁面热流的环形流道中的能量方程。然后把基本解推广到壁面热流沿轴向变化的棒束流道中。理论结果与实验结果吻合良好。研究结果表明,液钠的热入口效应与普通流体很不相同。 相似文献
5.
治癌专用重离子加速器HITFiL中同步加速器的注入系统采用了剥离注入方式。剥离膜的存在使束流克服了刘维定理的限制从而累积达到较高流强,但粒子多次穿越剥离膜也会造成束流损失并使得束流品质变坏,其中包括:1)粒子从膜原子中俘获电子使粒子电荷态发生改变而导致束流损失;2)剥离膜对束流的多重库仑散射导致束流发射度增长;3)束流在剥离膜中的能损及能量岐离导致束流中心动量减少并使得动量分散增长。本文通过研究剥离注入过程中粒子与物质的相互作用规律,用蒙特卡罗方法建立了剥离膜与粒子的作用模型,在对ACCSIM程序改进的基础上研究了剥离膜对束流的影响。 相似文献
6.
在回旋加速器中,如果磁极的镜像对称被破坏,将在加速器的中心平面上产生一水平分量的场Br,在粒子相应轴向共振的作用下,这样的场将使中心粒子的运动偏离中心平面,进而使束流发射度发生变化。在回旋加速器中粒子由于径向磁场作用偏离中心平面运动的方程可表示为: 相似文献
7.
8.
In a 2.45 GHz electron cyclotron resonance(ECR) ion thruster powered with rod antenna under a cross magnetic field, abnormal behaviours such as sudden drop of ion beam current(Ib) and larger increasing-rate of Ibin the high microwave power(Pw) discharges at high gas flow rates were observed. A differential method was proposed to reveal the changes in the radial profiles of gray values extracted from the end-view discharge images. The increasing-rate of Ibwith respect to Pwwas used to evaluate efficiencies of ion production and transport. Analyses indicate that discharges are dominantly sustained by ordinary wave via electron heating in the electron plasma resonance layer that can shift along the rod-antenna, and extraordinary wave can only ignite a discharge in the ECR layer in the low gas flow rate regime. In terms of the confinement region defined by the magnetic field lines intercepting with the screen grid, the confinement region of the optimized 2.45 GHz cross magnetic field takes the shape of hourglass, enabling the high increasing-rate of I_b with respect to P_w in high power discharges at high gas flow rates.Correlated with the accompanied bright boundary layer appearing in the differentiated image, the sudden drop of I_b in the low gas flow rate regime is attributed to the discharge ignited by the enhanced extraordinary wave in the ECR layer neighbouring the narrowest confinement region,where the produced ions can promptly enter the loss region. 相似文献
9.
Fangjun Xu Guangwei Guo Xinxin Ma G.E. Ozur 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2010,268(15):2395-2056
The influence of high current pulsed electron beam (HCPEB) irradiation numbers on the microstructure, wear and corrosion resistance properties of M50 steel was studied. The crystallize phase, surface morphology, hardness, oxidation wear and corrosion resistance of samples were analyzed using XRD, SEM, nanoindenter, wear tester and electrochemical corrosion tests. The results reveal that the hardness and wear resistance of irradiated samples decrease compared with untreated sample because of the increasing of austenite content in the melted layer; while the corrosion resistance of irradiated samples is higher than untreated sample. 相似文献
10.
11.
《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2004,217(1):136-142
In this work the effect of gas mixing on the production efficiency of ion beams extracted from an ECR ion source has been studied with the JYFL 6.4 GHz electron cyclotron resonance ion source (ECRIS). It was found that the gas mixing affects strongly the confinement of ions in the plasma of the ECRIS. The information obtained can be used to minimize the consumption of expensive materials or isotopes and to reduce contamination of the plasma chamber. It was observed that the carbon contamination, which is built up when the MIVOC method is used could be decreased with the aid of the gas mixing technique. The best mixing gas for this purpose was found to be oxygen. 相似文献
12.
We developed a cubic non-linear theory describing the dynamics of the multiharmonic spacecharge wave (SCW),with harmonics frequencies smaller than the two-stream instability critical frequency,with different relativistic electron beam (REB) parameters.The self-consistent differential equation system for multiharmonic SCW harmonic amplitudes was elaborated in a cubic non-linear approximation.This system considers plural three-wave parametric resonant interactions between wave harmonics and the two-stream instability effect.Different REB parameters such as the input angle with respect to focusing magnetic field,the average relativistic factor value,difference of partial relativistic factors,and plasma frequency of partial beams were investigated regarding their influence on the frequency spectrum width and multiharmonic SCW saturation levels.We suggested ways in which the multiharmonic SCW frequency spectrum widths could be increased in order to use them in multiharmonic two-stream superheterodyne free-electron lasers,with the main purpose of forming a powerful multiharmonic electromagnetic wave. 相似文献
13.
In the design of negative hydrogen ion sources,a magnetic filter field of tens of Gauss at the expansion region is essential to reduce the electron temperature,which usually results in a magnetic field of around 10 Gauss in the driver region,destabilizing the discharge.The magnetic shield technique is proposed in this work to reduce the magnetic field in the driver region and improve the discharge characteristics.In this paper,a three-dimensional fluid model is developed within COMSOL to study the influence of the magnetic shield on the generation and transport of plasmas in the negative hydrogen ion source.It is found that when the magnetic shield material is applied at the interface of the expansion region and the driver region,the electron density can be effectively increased.For instance,the maximum of the electron density is 6.7×1017 m-3 in the case without the magnetic shield,and the value increases to 9.4×1017 m-3 when the magnetic shield is introduced. 相似文献