Distance between electrons in electron beam?

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Discussion Overview

The discussion centers on determining the average distance between electrons in an electron beam, specifically in the context of a cathode ray tube. Participants explore the factors influencing this distance, including beam geometry, intensity, and electron velocity.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • Some participants suggest that the average distance between electrons can be approximated, but additional information about the beam's geometry and intensity is necessary.
  • There is a proposal that knowing the beam's intensity and the velocity of the electrons allows for the calculation of the number of electrons in the beam, which can then be used to determine the average interelectron distance.
  • One participant inquires about the specific formula needed for these calculations and requests references.
  • Another participant raises the need for typical values, such as beam size and the number of electrons generated by a tungsten filament at a specific temperature and current, to facilitate the calculations.
  • Questions are posed regarding the density of electrons in the beam as it enters and exits the slit, as well as the average velocity of the electrons during this process.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the average distance between electrons, as multiple factors and conditions are discussed without definitive conclusions. The discussion remains unresolved regarding specific calculations and typical values.

Contextual Notes

Limitations include the need for specific definitions of beam geometry and intensity, as well as unresolved mathematical steps related to the calculations of electron density and velocity.

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What is the average distance between electrons in an electron beam such as produced in a cathode ray tube as they pass through the slit and then as they pass through the charged horizontal plates and magnetic coils etc that produce the deflection?
 
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Well one can approximate the spacing but more info is needed for that. The geometry and intensity of the beam would have to be known.
 
inha said:
Well one can approximate the spacing but more info is needed for that. The geometry and intensity of the beam would have to be known.
What is the formula? reference?
 
It can be figured out. If you know the beam's intensity (impulse) and the electron's velocity, you know how many electrons you have in the beam. If you know beam size, you can calcuylate the average interelectron difference.
 
Of course. The question then is what is an example of a typical beam size or number of electrons generated by a tungsten filament at a typical temperature associated with a specific current and pulled toward the plate containing the slit, say 10kV relative to the voltage at the filament, emerging through a slit of a typical size say of cross section area A? And then what is the density of electrons in the beam entering and emerging from this slit and the average velocity of the electrons as they pass through the slit?
 

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