What is an electron lens diameter?

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    Diameter Electron Lens
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SUMMARY

The discussion centers on the concept of 'electron lens diameter' in the context of a computer simulation using Simion, an ion simulation program. The term refers specifically to the diameter of the electron lens, which is crucial for understanding the equipotential lines formed by the lens. The user seeks clarification on whether 'lens diameter' pertains to the gap distance between two cylinders or the distance across the bulge of the lens. Additionally, they inquire about graphing 'lens diameters' alongside voltage ratios and focal lengths, highlighting the complexity of representing three variables on a two-dimensional graph.

PREREQUISITES
  • Understanding of electron optics and lens theory
  • Familiarity with Simion software for ion simulation
  • Basic knowledge of graphing techniques in physics
  • Proficiency in using the lens formula: 1/P + 1/Q = 1/f
NEXT STEPS
  • Research the principles of electron lens design in electron microscopes
  • Explore how to graph multiple variables in physics, particularly in optics
  • Learn about equipotential lines and their significance in electron optics
  • Investigate the relationship between focal lengths and lens diameters in electron lenses
USEFUL FOR

Students and professionals in physics, particularly those studying electron optics, as well as researchers working with electron microscopes and ion simulation software.

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On a computer simulation (Simion - ion simulating program) I've got two cylinders (with a small gap between them) through which an electron beam goes through. I understand that the "lens" refers to the equipotential lines, since they form a bulge at each end, just like an optical lens. What does 'lens diameter' mean? The distance of the gap, or the distance from one end of the 'bulge' to the other end? That's the basic question I have - the rest is more details on the rest of my task if you want to help.

I need to re-construct a graph for work, it shows 'lens diameters' on the y axis, going from +2 to +10 above the x-axis, then again from +2 to +10 below the x-axis (what does that mean anyway, why both above and below?). Then it shows "V2 / V1" on the x-axis.. and the line above the x-axis looks like it's exponentially decreasing while the line below the x-axis looks like it's exponentially increasing.. the lines are labeled F1 and F2, for focal lengths. The top and bottom of the x-axis are mirror images.

So.. I can set which voltages I want, and I can figure out the focal length of the beam through the equation 1/P + 1/Q = 1/f.

What does it mean by 'lens diameter?' How do I measure that? And how can this be an x vs. y graph if there are three terms? The diameters, V2/V1 ratio, and the focal length lines. I'm confused on how you can have three of them on a two-part (x and y) graph.

Any help or guidance in the right direction would be greatly appreciated!
Note: I've only taken general physics I and II, so my knowledge isn't very extensive, just kind of got thrown into this.
 
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Electron lens diameter is the diameter of the electron lens. Electron microscope manufacturers have optimized the design of the electron lens to give the largest useful field of view. Most electron microscopes have a lens designed to give a useful field of view of between 20 and 200 micrometers. In the scanning electron microscope the sample is scanned over the electron beam in a raster pattern.
 

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