共查询到18条相似文献,搜索用时 218 毫秒
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轴对称收敛型电子枪设计方法再讨论 总被引:8,自引:4,他引:4
对轴对称收敛型电子枪设计方法进行了整理分析,就阴极半锥角的初始值对迭代综合法的收敛性能所产生的影响进行了讨论,针对低压缩比条件下原来的Vaughan公式失效的问题进行了分析,给出了更为合理的初始值计算公式。采用修正后的公式和迭代综合法对电子枪进行设计,在高压缩比情况下的设计结果与采用原来Vaughan方法的结果完全一致;而对于低压缩比的情况,也得到了合理的设计,从而解决了原来的Vaughan方法在低压缩比情况下失效的问题,扩大了迭代综合法的应用范围。 相似文献
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BEPCII改进工程需要更高流强的电子枪。新电子枪系统的物理设计、机械设计、控制系统设计等均进行了描述。电子枪的设计发射电流在脉宽为1 ns时大于10 A,重复频率50 Hz。将会采用脉冲电源来为电子枪提供最高200 kV的脉冲高压。在设计阶段,电子枪的几何结构和束流传输过程利用计算机模拟进行了优化。EGUN和DGUN的计算结果表明导流系数为0.22 mA·V-3/2,电子枪出口的发射度为16 p·mm·mrad。PARMELA的模拟结果表明束流能顺利地传输至第一根加速管末端,捕获效率为67%,出口的均方根发射度为25 mm·mrad。基于EPICS平台的电子枪控制系统设计也已完成,提供了全新的双脉冲运行模式和2.5 μs长脉冲运行模式。 相似文献
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W波段扩展互作用速调管电子光学系统由皮尔斯电子枪与均匀永磁聚焦系统组成,用于电子注的产生与传输。利用Vaughan迭代综合法及数值模拟优化设计了皮尔斯电子枪,并按照电子注传输特性要求研制了均匀永磁聚焦结构。根据电子光学系统的三维模拟,导流系数0.21 P,注电流大于0.5 A,注平均半径小于0.3 mm,射程大于11 mm。永磁聚焦磁场约0.33 T,传输距离大于50 mm,电子注通过率达到100%。电子枪与聚焦系统已加工完毕并通过测试,技术指标满足要求。 相似文献
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ZEMAX和CODE V等光学设计软件,虽然有很强的优化功能,但如果想得到好的设计结果,初始解的选择至关重要。求初始解的普遍做法是,将已有的光学系统或其中某一个组元拿来进行缩放。这种办法带有盲目性。另一种方法就是利用高斯光学和三级像差理论求变焦距物镜的初始解。这一方法有助于创新设计,但却很少被应用。本文介绍了作者在运用这一方法过程中产生的观点、理念、经验和成果。本文通过一个十倍变焦距物镜设计实例,详细介绍了求初始解的过程,为了验证该初始解的效果,还用ZEMAX进行了像差优化。为了增加说服力,设计过程的每一步,都给出了具体的数据,包括经ZEMAX优化得到的最后结果。 相似文献
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Mathuthu M. Zengeni T.G. Gholap A.V. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1997,25(6):1382-1388
A simplified theory for preliminary design of plasma focus devices that starts at the breakdown phase is proposed. For best focus, it is shown that the model can be used to predict the values of the inner and outer electrode radius, inner electrode length, gas pressure, and charging voltage that give minimum possible pinch radius. The theoretical results agree with experimental observations. The model shows that of these parameters, inner electrode length, inner and outer electrode radii play a significant role. An optimum pinch radius ratio of 0.05 to 0.40 was realized. Test results show that the focus strength is dependent on the breakdown conditions via the initial and final velocities of the current sheath during the radial collapse phase and the axial rundown phase. The final axial velocity determines the initial inward radial velocity. Results for a test design are presented 相似文献
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O. F. Panchenko 《Technical Physics》1999,44(6):692-694
A theoretical interpretation is put forward for the fine structure of the secondary electron emission spectra of Ir normal
to the (111) surface and the total current spectrum of an Ir polycrystal. The calculations took into account the energy dependence
of the broadening of the energy band levels, the electron-electron and electron-plasmon contributions to the nonequilibrium
electron distribution function, and the isotropic component of the current from the electrons scattered at the surface. It
is shown that the fine structure of the secondary electron emission spectrum and the total current spectrum is mainly attributable
to the electron structure of the final states into which the electrons enter or from which they are emitted so that the characteristics
of the band configuration in the energy band structure can be reconstructed directly from the experimental data. This method
can be used to separate bulk effects from surface effects in the secondary electron emission and total current spectra. It
is confirmed that the fine structure of the secondary electron emission and total current spectra depends on the geometric
structure and the degree of ordering of the crystals. A reduction in the intensity of the fine structure serves as a measure
of the defect structure in the surface region of the sample which can be successfully used to monitor the surface state during
treatment.
Zh. Tekh. Fiz. 69, 94–96 (June 1999) 相似文献
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A preliminary analysis of plasma current quenching is presented in this paper based on the disruption database.It demonstrates that 26.8%of discharges have been disrupted in the last 2012 campaign,in addition,the plasma disruptive rate grows with the increase of plasma current.The best-fit linear and instantaneous plasma current quench rate is extracted from the recent EAST disruptions,showing that an 80%-30%interval of the maximum plasma current is well fit for the EAST device.The lowest area-normalized current quench time is 3.33 ms/m~2 with the estimated plasma electron temperature being 7.3 eV~ 9.5 eV.In the disruption case the maximum eddy current goes up to 400 kA,and a fraction of currents are respectively driven on the upper and lower outer plate with nearly 100 MPa-200 MPa stress in the leg. 相似文献
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Constructions and Preliminary HV Conditioning of a Photocathode Direct-Current Electron Gun at IHEP 下载免费PDF全文
《中国物理快报》2017,(7)
As one of the most important key technologies for future advanced light source based on the energy recovery linac, a photocathode dc electron gun is supported by Institute of High Energy Physics(IHEP) to address the technical challenges of producing very low emittance beams at high average current. Construction of the dc gun is completed and a preliminary high voltage conditioning is carried out up to 440 kV. The design,construction and preliminary HV conditioning results for the dc gun are described. 相似文献
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利用基于虚边界元法的VBGUN程序和基于边界元法的MOM程序,对一折叠波导毫米波行波管的电子光学系统进行了设计。设计过程中使用计算相关性系数的方法调节参数,通过计算敏感性系数以考察加工误差带来的影响。设计过程显示:低导流系数、小束腰、高压缩比的毫米波电子枪的层流性与电极尺寸相关性很大,易受到加工误差的影响;聚束系统的设计难点在于轴上峰值磁感应强度要受到漂移管半径的限制,这一点可以通过提高工作电压和降低电流来平衡,因此它的设计必须与慢波结构的设计同时进行。 相似文献