Study of Displacement Value of the Electron-Beam in the Electron Gun in Electron-Beam Furnace

2013 ◽  
Vol 652-654 ◽  
pp. 2391-2394
Author(s):  
Dong Hui Zhang ◽  
Chun Dong Liu ◽  
Jian Ming Liang ◽  
Chang Sheng Li
Keyword(s):  
Mathematical Model ◽  
Electron Beam ◽  
Space Charge ◽  
Molten Metal ◽  
Space Charge Effect ◽  
Electron Gun ◽  
Ideal Condition ◽  
Charge Effect ◽  
Beam Spot ◽  
The Ideal

The concept of maximal and minimal displacement value of the electron-beam was proposed considering the influence of space charge effect based on the displacement value of the electron-beam in the process of magnetic deflection scanning in the ideal condition. The deduction of mathematical model of the maximal and minimal displacement value was accomplished. The position of the beam spot can be more accurately controlled by the model, thus it is made sure that un-molten metal is bombarded by the beam spot accurately, which can increase the melt quality.

New type electron gun with electrostatic and electromagnetic lenses

1978 ◽  
Vol 36 (1) ◽  
pp. 62-63
Author(s):  
T. Ichinokawa ◽  
H. Maeda
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Optimum Condition ◽  
Bias Voltage ◽  
Electron Gun ◽  
Charge Effect ◽  
Micro Fabrication ◽  
Maximum Brightness ◽  
New Type ◽  
The Ideal

I. IntroductionThermionic electron gun with the Wehnelt grid is popularly used in the electron microscopy and electron beam micro-fabrication. It is well known that this gun could get the ideal brightness caluculated from the Lengumier and Richardson equations under the optimum condition. However, the design and ajustment to the optimum condition is not so easy. The gun has following properties with respect to the Wehnelt bias; (1) The maximum brightness is got only in the optimum bias. (2) In the larger bias than the optimum, the brightness decreases with increasing the bias voltage on account of the space charge effect. (3) In the smaller bias than the optimum, the brightness decreases with bias voltage on account of spreading of the cross over spot due to the aberrations of the electrostatic immersion lens.In the present experiment, a new type electron gun with the electrostatic and electromagnetic lens is designed, and its properties are examined experimentally.

scholarly journals Manipulation of Laser Distribution to Mitigate the Space-Charge Effect for Improving the Performance of a THz Coherent Undulator Radiation Source

Particles ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 238-252 ◽  
Author(s):  
Siriwan Krainara ◽  
Shuya Chatani ◽  
Heishun Zen ◽  
Toshiteru Kii ◽  
Hideaki Ohgaki
Keyword(s):  
Electron Beam ◽  
Space Charge ◽  
Electron Bunch ◽  
Beam Quality ◽  
Space Charge Effect ◽  
Bunch Length ◽  
Charge Effect ◽  
Simulation Code ◽  
Undulator Radiation ◽  
Radiated Power

A THz coherent undulator radiation (THz-CUR) source has been developed at the Institute of Advanced Energy, Kyoto University. A photocathode Radio-Frequency (RF) gun and a bunch compressor chicane are used for generating short-bunch electron beams. When the electron beam energy is low, the space-charge effect strongly degrades the beam quality, such as the bunch length and the energy spread at the high bunch charge condition at around 160 pC, and results in the reduction of the highest frequency and the maximum radiated power of the THz-CUR. To mitigate the space charge effect, we have investigated the dependence of the electron beam quality on the laser distribution in transverse and longitudinal directions by using a numerical simulation code, General Particle Tracer GPT. The manipulation of the laser distribution has potential for improving the performance of the THz-CUR source. The electron bunch was effectively compressed with the chicane magnet when the laser transverse distribution was the truncated Gaussian profile, illuminating a cathode. Moreover, the compressed electron bunch was shortened by enlarging the laser pulse width. Consequently, an enhancement of the radiated power of the THz-CUR has been indicated.

Study of Electron Beam Space Charge Effect of Electrostatic Focusing

2014 ◽  
Vol 602-605 ◽  
pp. 2986-2990
Author(s):  
De Wang
Keyword(s):  
Electron Beam ◽  
Space Charge ◽  
Computer Aided Design ◽  
Space Charge Effect ◽  
Charge Effect ◽  
Distribution Method ◽  
Beam Focusing ◽  
Computer Aided ◽  
Aided Design

The influence of space charge in the space electron beam focusing system is introduced.Then charge-quantity distribution method which is used to calculate the density of space charge and the Computer Aided Design (CAD) method are put forward The result by programming calculation shows that the method is correct.

Electron beam modeling and analyses of the electric field distribution and space charge effect

2021 ◽  
Author(s):  
Jiang Yueling ◽  
Dong Quanlin
Keyword(s):  
Electron Beam ◽  
Electric Field ◽  
Space Charge ◽  
Field Distribution ◽  
Electric Field Distribution ◽  
Space Charge Effect ◽  
Electron Beam Current ◽  
Field Calculation ◽  
Charge Effect ◽  
Cross Sectional

Abstract In electron beam technology, the critical focus of research and development efforts is on improving the measurement of electron beam parameters. The parameters are closely related to the generation, emission, operation environment, and role of the electron beam and the corresponding medium. In this study, a field calculation method is proposed, and the electric field intensity distribution on the electron beam’s cross-section is analyzed. The characteristics of beam diffusion caused by the space charge effect are investigated in a simulation, obtained data are compared with the experiment. The simulation demonstrated that the cross-sectional electric field distribution is primarily affected by the electron beam current, current density distribution, and electron beam propagation speed.

scholarly journals A novel numerical calculation method for electron guns

2014 ◽  
Vol 32 (3) ◽  
pp. 487-493 ◽  
Author(s):  
Y.F. Kang ◽  
J. Zhao ◽  
J.Y. Zhao ◽  
T.T. Tang
Keyword(s):  
Space Charge ◽  
Current Density ◽  
Current Density Distribution ◽  
Space Charge Effect ◽  
Electron Gun ◽  
Charge Effect ◽  
Thermal Velocity ◽  
Electron Guns ◽  
Two Factors ◽  
Numerical Calculation Method

AbstractThe problem of initial thermal velocity and the space charge effect of electron guns in numerical simulations have been investigated deeply. In general, the current software can meet the engineering requirements. However, the electron's initial thermal velocity and the space charge effect lack sufficient consideration. The above two factors significantly limit the performances of electron guns. Moreover, the parameters of electron guns are approximated based on a limited number of electron trajectories. Thus, the statistical distribution of the beam electron resulting from its initial thermal velocity is not considered adequately in present software. This paper introduces the equivalent meridional projected trajectory equation and the curvilinear axis evolution theory of the current density of toroidal electron sub-beam, and subsequently the current and charge density distributions in electron guns can be derived through iteration calculation. Based upon, the virtual crossover of an electron gun is determined by its current density distribution. As well as, a relevant numerical algorithm is developed and the related program is modified based on the popular commercial software SOURCE. Tungsten cathode guns, LaB6 cathode guns, field mission guns and Pierce guns are simulated respectively by examples. The calculations prove that the modified software is effective and practical.

scholarly journals Space-Charge Effect on the Theoretical Design of Electron Gun Operated under Zero Magnification Condition

2014 ◽  
Vol 11 (2) ◽  
pp. 572-576
Author(s):  
Baghdad Science Journal
Keyword(s):  
Space Charge ◽  
Focal Length ◽  
Chromatic Aberration ◽  
Space Charge Effect ◽  
Electron Gun ◽  
Three Dimension ◽  
Charge Effect ◽  
Charged Particle Optics ◽  
Particle Optics ◽  
Paraxial Ray

A computational investigation is carried out in the field of charged –particle optics with the aid of numerical analysis method using the personal computer. The work is concerned with the design of electron gun with space-charge effect. The Finite element method (FEM) used in the solution of Poison's equation for determine the axial potential distribution of the two-electrode immersion lens operated under zero magnification condition , and from the solution of the paraxial ray equation the optical properties such as the focal length , spherical and chromatic aberration coefficients are determined, also a calculation of the brightness and perveance for the lens. The electrodes geometry was determined in two and three dimension with the aid of new drawing software called SIMION 7 and the electron beam trajectory under zero magnification conditions has been determine for these electrodes.

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