Degradation of a pure platinum aperture after electromagnetic rad. overexposue

In summary, the use of a backscatter electron detector allows for the observation of structural features below the surface of materials. This is possible due to the deflection of beam electrons passing close to a nucleus, resulting in brighter images. In the case of a pure platinum aperture, prolonged exposure to an electron beam leads to a buildup of electrons and subsequent variations in the resulting pattern. Gold, with its higher atomic number, does not experience this buildup and therefore does not exhibit variations in its aperture pattern with prolonged exposure.
  • #1
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A platinum aperture from a transmission electron microscope exhibits atomic variations after prolonged exposure to electromagnetic radiation. A gold aperture on the other hand does not.

Using a backscatter electron detector we can observe sturctural features of materials below the surface. This is possible because beam electrons passing close to a nucleus (higher atomic number, higher interaction probability, thus higher signal and brighter image) are defracted, over and over until exiting the top of the specimen.

Anyway, the above may not be correct and any corrections or comments are encouraged.

The question at hand is what happens to a pure platinum aperture, internally, that give the resulting pattern:

http://i.imgur.com/u545w.png

This was taken using a backscatter electron detector at ~550x in compositional mode.
 
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  • #2
Platinum has an atomic number of 78, which is high enough to cause significant interaction with the beam electrons. As the beam electrons pass through the aperture, they interact with the platinum atoms in the material and cause a buildup of electrons on the surface. This causes a redistribution of the original electron density within the aperture, leading to the pattern seen in the image. Prolonged exposure to an electron beam will lead to further buildup of electrons, causing variations in the pattern. Gold, on the other hand, has an atomic number of 79 and does not experience the same buildup of electrons, so its aperture pattern does not vary with prolonged exposure.
 

1. What is the cause of degradation in a pure platinum aperture after electromagnetic radiation overexposure?

The degradation in a pure platinum aperture after electromagnetic radiation overexposure is caused by the exposure to high levels of electromagnetic radiation. This radiation can cause structural changes in the platinum, leading to a decrease in its performance and functionality.

2. How does electromagnetic radiation affect a pure platinum aperture?

Electromagnetic radiation can cause changes in the structure of a pure platinum aperture, leading to a decrease in its performance. This can result in a decrease in the aperture's durability, precision, and ability to withstand high temperatures.

3. Can the degradation of a pure platinum aperture be reversed?

Unfortunately, the degradation of a pure platinum aperture after electromagnetic radiation overexposure cannot be reversed. The structural changes caused by the radiation are irreversible, and the aperture will continue to deteriorate over time.

4. Are there any preventive measures that can be taken to avoid degradation of a pure platinum aperture?

There are several preventive measures that can be taken to avoid degradation of a pure platinum aperture after electromagnetic radiation overexposure. These include limiting the exposure to high levels of radiation, using protective coatings or materials, and regularly monitoring and maintaining the aperture's condition.

5. How can the performance of a degraded pure platinum aperture be restored?

Unfortunately, the performance of a degraded pure platinum aperture cannot be fully restored. However, in some cases, the aperture can be repaired or replaced to improve its functionality. It is important to regularly monitor and maintain the aperture to prevent further degradation.

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