Conceptual question on wave-particle duality (electron microscope)

  • #1
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Main Question or Discussion Point

according to wave particle duality particles such as electrons exhibit wave like properties.
and the wavelngth is given by lambda=h/p, so increase momentum and get shorter lambda.

This property is utilised in the electron microscope to get very short wavelengths and so have very high resolution when looking at specimens.

My question is, why do they need electrons to do this? why not just shine electromagnetic radiation of very short wavelength (eg x-rays or gamma rays) on the specimen to get equally sharp resolution?
 

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  • #2
ZapperZ
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according to wave particle duality particles such as electrons exhibit wave like properties.
and the wavelngth is given by lambda=h/p, so increase momentum and get shorter lambda.

This property is utilised in the electron microscope to get very short wavelengths and so have very high resolution when looking at specimens.

My question is, why do they need electrons to do this? why not just shine electromagnetic radiation of very short wavelength (eg x-rays or gamma rays) on the specimen to get equally sharp resolution?
Because at those very short wavelength, the energy of each photons can be so high, it would either vaporize, or cause damage to your sample. Furthermore, you also have issues with penetration depth.

Zz.
 
  • #3
Ygggdrasil
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You are correct that we would be able to get high resolution images of objects using x-rays and gamma rays in theory. In practice, however, it is difficult to focus high energy EM radiation (it tends to destroy any type of lens we put into the optical path). So, while we can collect diffraction information (which does contain the high resolution information of the sample, this is how crystallography works), we cannot produce an image without a way to refocus the light.

Electrons are convenient because they can be focused using magnets.
 
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Demystifier
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Because at those very short wavelength, the energy of each photons can be so high, it would either vaporize, or cause damage to your sample.
The energy of an electron with the same wavelength is even higher.

I believe the true reason might be the fact that the interaction effects between a photon and a unit charge are proportional to alpha=1/137, while the interaction effects between two unit charges are proportional to alpha^2 which cause a much smaller damage.
 
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ZapperZ
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The energy of an electron with the same wavelength is even higher.

I believe the true reason might be the fact that the interaction effects between a photon and a unit charge are proportional to alpha=1/137, while the interaction effects between two unit charges are proportional to alpha^2 which cause a much smaller damage.
No, I think Ygggdrasil has given a more relevant/practical reasons why.

Zz.
 
  • #6
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You are correct that we would be able to get high resolution images of objects using x-rays and gamma rays in theory. In practice, however, it is difficult to focus high energy EM radiation (it tends to destroy any type of lens we put into the optical path). So, while we can collect diffraction information (which does contain the high resolution information of the sample, this is how crystallography works), we cannot produce an image without a way to refocus the light.

Electrons are convenient because they can be focused using magnets.
Yes, the problem is in focusing X-rays and gamma rays, but not exactly because they tend to destroy the lens; I'd say instead it's because lenses doesn't focuse x-gamma rays at all (very complicated metal surfaces can be used to focus x-rays by high-incidence reflection).
Furthermore those rays are not very easy to generate at a specified frequency, and are not easy to manage for human safety.
 

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