CMA (Cylindrical Mirror Analyzer)

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Discussion Overview

The discussion centers around the workings and applications of a Cylindrical Mirror Analyzer (CMA), particularly in the context of analyzing electrons emitted from materials. Participants express interest in understanding the physics behind the instrument, its advantages over other analytical tools, and seek deeper insights into its operational principles.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants express confusion about how the CMA operates and how its readings are interpreted, particularly in relation to photoemission.
  • One participant clarifies that the CMA detects electrons rather than photons, specifically in the context of Auger electron spectroscopy.
  • Another participant notes that the CMA is analogous to a spectrometer, emphasizing its higher energy resolution and ability to adjust the energy range of interest.
  • There is a request for more detailed technical understanding of the CMA's functionality, beyond conceptual explanations, and inquiries about available resources or manuals.
  • Some participants acknowledge the need for a clearer understanding of the differences between a CMA and other instruments like spectrometers or CCD cameras.

Areas of Agreement / Disagreement

Participants generally agree on the basic function of the CMA as an electron analyzer but express differing levels of understanding regarding its operational details and advantages compared to other analytical methods. The discussion remains unresolved regarding specific technical aspects and available resources for deeper learning.

Contextual Notes

Participants mention limitations in available literature and resources, indicating a potential gap in accessible technical information about CMAs. There is also uncertainty about the specific operational principles and configurations of the CMA.

RaulTheUCSCSlug
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I'm supposed to be working with a CMA (Cylindrical Mirror Analyzer), but I'm more interested in the physics behind it. This is the instrument in question that we are looking to get:

http://www.rbdinstruments.com/products/micro-cma.html

We want it to look at different eV levels of different wavelengths and how it compares to the theoretical values we are looking to get. I know it works off of photoemission, but kind of confused how the readings work? I'm confused on how/why it works and there's nothing on Wikipedia that I can find on it to go off of. This is similar to the set up we are looking at:

https://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/AES_Setup2.JPG/340px-AES_Setup2.JPG

Where the Ion source will be something like an electron gun, and the electron gun in the photo would be the microCMA.

What makes this set up different from say a spectrometer, or using a CCD camera or something else of the sort? What's the advantage here that I'm not seeing?
 
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RaulTheUCSCSlug said:
I'm supposed to be working with a CMA (Cylindrical Mirror Analyzer), but I'm more interested in the physics behind it. This is the instrument in question that we are looking to get:

http://www.rbdinstruments.com/products/micro-cma.html

We want it to look at different eV levels of different wavelengths and how it compares to the theoretical values we are looking to get. I know it works off of photoemission, but kind of confused how the readings work? I'm confused on how/why it works and there's nothing on Wikipedia that I can find on it to go off of. This is similar to the set up we are looking at:

https://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/AES_Setup2.JPG/340px-AES_Setup2.JPG

Where the Ion source will be something like an electron gun, and the electron gun in the photo would be the microCMA.

What makes this set up different from say a spectrometer, or using a CCD camera or something else of the sort? What's the advantage here that I'm not seeing?
Aren't you detecting electrons not photons? Certainly for Auger electron spectroscopy it's the electrons you detect, not the photon.
 
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RaulTheUCSCSlug said:
I'm supposed to be working with a CMA (Cylindrical Mirror Analyzer), but I'm more interested in the physics behind it. This is the instrument in question that we are looking to get:

http://www.rbdinstruments.com/products/micro-cma.html

We want it to look at different eV levels of different wavelengths and how it compares to the theoretical values we are looking to get. I know it works off of photoemission, but kind of confused how the readings work? I'm confused on how/why it works and there's nothing on Wikipedia that I can find on it to go off of. This is similar to the set up we are looking at:

https://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/AES_Setup2.JPG/340px-AES_Setup2.JPG

Where the Ion source will be something like an electron gun, and the electron gun in the photo would be the microCMA.

What makes this set up different from say a spectrometer, or using a CCD camera or something else of the sort? What's the advantage here that I'm not seeing?

It is analogous to a spectrometer, or to be specific, electron spectrometer since it analyzes only electrons. However, it has the capability of having a higher energy resolution, and is able to change the range of energy of interest within its analyzer window.

All the analyzer does is look at the energy spectrum (although for spherical analyzer, both energy and momentum spectrum can be obtained) of the electrons. Where the electrons come from doesn't really matter, and that is where the material or source being studied comes into play.

I'm not sure if you are simply asking for a conceptual understanding of what it does, or if you are really looking for the nuts-and-bolts of how it works in detail (the latter you can easily do a search on).

Zz.
 
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Yes, my understanding was that it was like a spectrometer but wasn't sure what the advantage was.

I thought we were going to be looking at the diffraction grating, but you are correct. It's the Auger electrons we'll be looking at. I was looking more for a deeper understanding than conceptual on how a CMA works, can't find much from Google (well a couple things, but doesn't leave me satisfied). Although the Wiki page gave me a fairly clear understanding of the set up and cleared up some of the confusion, I'm still not sure what goes on in a CMA.

Is there a technical manual of one or a book to reference? Or would I be left to look at several concepts and piece the information together? Thanks btw.
 

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