Why Doesn't Electron Shielding Block RF Radiation?

In summary, the video explains that a proton in a magnetic field will align with the magnetic field very easily if there is no shielding from electrons, and therefore will require energy to shift to the opposite spin state. However, if there is more shielding, the proton will be less effected by the magnetic field and therefore will require less energy to move it to the opposite spin state.
  • #1
CuriousBanker
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TL;DR Summary
I understand why shielding lowers the effect of a magnetic field, but why doesn't it lower the effect of RF radiation?
I am watching this video;

at the 8:20 mark it shows that a proton in a magnetic field will align with the magnetic field very easily if there is no shielding from electrons, and therefore will require energy to shift to the opposite spin state; makes sense to me. I also understand that when there is more shielding, the proton will be less effected by the magnetic field and therefore will require less energy to move it to the opposite spin state. What I don't understand, is why don't the electrons shield the proton from the RF radiation? Electrons are effected by radiation (hence IR spectroscopy), so I'm curious as to why the RF radiation is not also shielded by the electrons. With no shielding it takes more energy to spin, but there is less shielding to block the radiation. With shielding it requires less energy to spin, but there is more shielding to block the radiation, so why isn't the same amount of radiation required to bring both nuclei into resonance? I'm guessing the answer is that RF radiation is not absorbed by electrons, whereas IR is? I don't know anything about the different types of radiation, or QM, so that's probably where my ignorance lies.

Thank you in advance
 
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  • #2
I only have a elementary knowledge of NMR but I think you are misinterpreting the use of the terms shielding/deshielding. I know when we talk about shielding we naturally think of the absorption of radiation or energy. But here the term is used only for the affect of nearby electrons on a proton's local magnetic environment. This "shielding" effect of the electrons reduces the local magnetic field near the proton under question. That is the shielding electrons counteract the applied magnetic field so that the energy needed to "flip" the magnetic moment is less than if the the proton is "out in the open" deshielded so to speak experiencing the full affect of the applied magnetic field. This shielding does not absorb energy. The use of the term shielding is irrelevant to the penetration of the applied RF energy to the proton.
 
  • #3
Short answer to the point and easy to understand. Thanks!
 
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Related to Why Doesn't Electron Shielding Block RF Radiation?

1. Why is electron shielding important in blocking RF radiation?

Electron shielding is important because it helps to reduce the penetration of electromagnetic radiation, such as RF radiation, into materials. This is because electrons in the material can absorb and dissipate the energy from the radiation, preventing it from reaching deeper into the material.

2. How does electron shielding work to block RF radiation?

Electron shielding works by creating a barrier between the radiation and the material. This barrier is created by the electrons in the material, which are negatively charged and can absorb the energy from the radiation. As the electrons absorb the energy, they create an opposing electric field that cancels out the electric field of the radiation, effectively blocking it from entering the material.

3. Can all materials block RF radiation through electron shielding?

No, not all materials can effectively block RF radiation through electron shielding. The effectiveness of electron shielding depends on the material's ability to absorb and dissipate the energy from the radiation. Materials with high electron density, such as metals, are better at electron shielding compared to materials with lower electron density, such as plastics.

4. Is electron shielding the only factor that determines a material's ability to block RF radiation?

No, there are other factors that can affect a material's ability to block RF radiation, such as its thickness, density, and composition. For example, a thicker material will provide more electron shielding compared to a thinner material. Additionally, the composition of the material can also play a role in its ability to block RF radiation.

5. Are there any potential risks associated with electron shielding?

There are no known risks associated with electron shielding itself. However, if a material is not able to effectively block RF radiation, it can lead to potential health risks for individuals who are exposed to the radiation. It is important to use materials with proper electron shielding capabilities in environments where RF radiation is present to reduce potential health risks.

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