排序方式: 共有35条查询结果,搜索用时 17 毫秒
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切伦科夫辐射是一种方向性极好的辐射,其辐射能量发射方向严格地与带电粒子的运动方向相关,辐射光携带了带电粒子的方向信息,利用这种特性可以进行电子束发散角及其分布的测量。在基于切伦科夫辐射原理的基础上,考虑电子与物质作用时的多重库仑散射、电离等效应,进行了电子束发散角测量的蒙特卡罗数值模拟程序的建模工作,并完成了理想电子束及具有发散角分布的电子束的测量技术模拟工作。大量模拟结果显示,这种测量方法是可行的,具有对电子束发散角分布进行直接测量的能力,并且其测量系统结构简单。 相似文献
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Megaelectronvolt ultrafast electron diffraction (UED) is a promising detection tool for ultrafast processes. The quality of diffraction image is determined by the transverse evolution of the probe bunch. In this paper, we study the contributing terms of the emittance and space charge effects to the bunch evolution in the MeV UED scheme, employing a mean-field model with an ellipsoidal distribution as well as particle tracking simulation. The small transverse dimension of the drive laser is found to be critical to improve the reciprocal resolution, exploiting both smaller emittance and larger transverse bunch size before the solenoid. The degradation of the reciprocal spatial resolution caused by the space charge effects should be carefully controlled. 相似文献
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The experimental result of terahertz (THz) coherent transition radiation generated from an ultrashort electron bunching beam is reported.During this experiment,the window for THz transmission from ultrahigh vacuum to free air is tested.The compact measurement system which can simultaneously test the THz wave power and frequency is built and proofed.With the help of improved Martin-Puplett interferometer and Kramers-Krong transform,the longitudinal bunch length is measured.The results show that the peak power of THz radiation wave is more than 80 kW,and its radiation frequency is from 0.1 THz to 1.5 THz. 相似文献
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RF deflecting cavity can be used for bunch length measurement and is designed to diagnose the beam produced by the photocathode electron gun which was built at Tsinghua University for the Thomson scattering experiment. Detailed discussion and calculation for measuring the 3.5 MeV bunch and another with further acceleration to 50 MeV, which is under development, are presented. A standing-wave deflecting cavity working at 2856 MHz is designed and the power feeding system has been planned. 相似文献
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Ultrafast imaging tools are of great importance for determining the dynamic density distribution in high energy density(HED) matter. In this work, we designed a high energy electron radiography(HEER) system based on a linear electron accelerator to evaluate its capability for imaging HED matter. 40 MeV electron beams were used to image an aluminum target to study the density resolution and spatial resolution of HEER. The results demonstrate a spatial resolution of tens of micrometers. The interaction of the beams with the target and the beam transport of the transmitted electrons are further simulated with EGS5 and PARMELA codes, with the results showing good agreement with the experimental resolution.Furthermore, the experiment can be improved by adding an aperture at the Fourier plane. 相似文献
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The CBPM is a kind of monitor which is used for the measurement of beam transverse position. It is becoming increasingly popular due to its high potential in resolution performance. In theory, the resolution can reach about 1 nanometer. In this paper, a rectangular CBPM is designed for it has better X-Y isolation than a cylindrical one. It has been simulated and measured, and the results agree with each other very well. The procedures and results for the simulation and the cold test will be shown later and it will be proved that this is a reliable method for the CBPM design. 相似文献
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回顾了几种磁控管理论模型,对这些理论模型中得到的电荷分布进行了分析。利用计算机对X波段磁控管进行PIC模拟,监视粒子相空间分布,并与理论结果进行对比,证明布里渊理论能部分解释轮轭层的高度及其内部的电荷密度分布,但模拟结果中电子在相空间存在一定的分布,而布里渊理论采用的是单粒子运动理论,因此无法解释模拟结果中轮轭边界下降沿特性。模拟得到的轮辐内电荷分布与各种理论均有较大差异,分析发现,不同的轮轭边界下降沿特性是造成差异的主要原因。讨论了利用导向中心流体理论得到更准确的轮辐内电荷分布的可能方法。 相似文献