How to interpret N(E) vs. E graphs when performing Auger spectroscopy

  • #1

Summary:

TL;DR : Can't figure out what N(E) vs. E graph means in AES

Main Question or Discussion Point

Hi all, my name's Ethan and I'm an undergraduate physics student conducting research on work functions this summer. I've been trying to understand the graphs of N(E) or N'(E) vs. auger electron energy for several days now, but I can't find in the literature what exactly N(E) or N'(E) are. I've seen N(E) referred to as electron yield, intensity, and even dI/dV, but nowhere have I seen a clear definition. I understand why N'(E) is often used instead of N(E), since the peaks where Auger electrons are emitted are often difficult to see on the N(E) graph, I just don't understand what either actually are. I've attached a picture below that shows an N'(E) vs. E graph for some more context. Thanks!
244673
 

Answers and Replies

  • #2
Please see p.396 of this short pdf for further context. This is an example of a source that does not quite clarify what N(E) and N'(E) are.
 

Attachments

  • #4
Maybe, this might be of help:
PDF]AES - Auger Electron Spectrosopy - Uni Ulm
Ah, thank you. I see that the author of this doc mentions that either the electron count or intensity is plotted vs. the kinetic energy. From what I've read about my particular setup, I will be using an electron multiplier to produce a greater number of electrons incident on the phosphor screen. I suppose, then, that the electron count itself isn't what's important. Rather, the relative change in the electron count is. Does this seem like a good assumption?
 
  • #5
Lord Jestocost
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Whether on prefers to measure N(E) or dN(E)/dE isn’t related to “importance”, but depends on the measurement conditions. The differential mode, dN(E)/dE, is preferred when there is a high background of secondary electrons, thus allowing a better assignment of the characteristic lines.
 
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  • #6
Whether on prefers to measure N(E) or dN(E)/dE isn’t related to “importance”, but depends on the measurement conditions. The differential mode, dN(E)/dE, is preferred when there is a high background of secondary electrons, thus allowing a better assignment of the characteristic lines.
Thank you, but can you describe what N(E) actually is? I know that my system has a preamp hooked up to the apparatus, which means that my computer receives a digitized analog voltage, so how is the "current" actually being measured? I assume that N(E) is this mysterious "current" just translated to a voltage, but how is the current actually measured?
 
  • #7
Lord Jestocost
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The output signal is generally proportional to the count rate of electrons, dN(E)/dt: the number of electrons, dN(E), with a given energy, E, which are counted by the detector in a given time interval, dt.
 

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