THE FINITE BEAM SPACE-CHARGE LIMITED DIODE AS A NOISE TRANSDUCER

1961 ◽  
Vol 39 (4) ◽  
pp. 568-578
Author(s):  
R. A. McFarlane
Keyword(s):  
Electron Beam ◽  
Space Charge ◽  
Shot Noise ◽  
Anode Voltage ◽  
Electron Gun ◽  
Beam Diameter ◽  
Noise Current ◽  
Space Charge Limited

A method is presented for calculating the noise properties of a cylindrical electron beam from a space-charge limited diode electron gun. The multivelocity character of the beam is considered and correction is made for finite beam diameter. The ratio of anode noise current to full shot noise is found to depend on ω1/2/V0a where ω is the frequency and V0a the anode voltage.

scholarly journals MICROWAVE NOISE IN ACCELERATED ELECTRON STREAMS

1961 ◽  
Vol 39 (4) ◽  
pp. 579-587
Author(s):  
R. A. McFarlane
Keyword(s):  
Electron Beam ◽  
Space Charge ◽  
Theoretical Calculations ◽  
Electron Gun ◽  
Current Fluctuations ◽  
Beam Diameter ◽  
Poor Agreement ◽  
Potential Minimum ◽  
Noise Current ◽  
Microwave Noise

Measurements have been made of the noise current fluctuations on the electron beam from a space-charge limited diode electron gun, at 1,400 Mc/s, 4,250 Mc/s, and 9,520 Mc/s. Theories which do not consider the finite beam diameter and the multivelocity nature of the stream in the region of the potential minimum are in poor agreement with experiment. The measurements here reported and those of other workers are compared with the results of theoretical calculations in which these two effects are considered. Significant improvement in agreement with experiment is realized.

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.

Influence of ion density on electron-beam propagation from a gas-filled diode

1999 ◽  
Vol 61 (1) ◽  
pp. 31-41 ◽  
Author(s):  
HAN S. UHM ◽  
E. H. CHOI ◽  
J. J. KO ◽  
H. M. SHIN ◽  
G. S. CHO
Keyword(s):  
Electron Beam ◽  
Theoretical Model ◽  
Ion Channel ◽  
Space Charge ◽  
Relativistic Electron ◽  
Relativistic Electron Beam ◽  
Space Charge Limited Current ◽  
Ion Density ◽  
Limited Current ◽  
Space Charge Limited

Electron-beam propagation from a gas-filled diode is investigated. The beginning portion of the electron beam pulse creates an ion channel not only inside the diode but also in the region beyond the anode. A theoretical model is developed for the space-charge-limited current of a relativistic electron beam propagating through an ion channel. A simple analytical expression for the space-charge-limited current is obtained within the context of a thin-beam approximation, where the conducting-tube radius is much larger than the beam radius. The beam current propagating through an ion channel is measured experimentally for a mildly relativistic electron beam. Whenever the ion density inside the diode is the same as the beam electron density, the diode is short-circuited. The ion-channel density at the short-circuiting time is calculated numerically and is used to estimate the space-charge-limited current. It is shown that the experimental data agree well with the analytical results predicted by the theoretical model.

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