Is Visible Light Bremsstrahlung Observable in Transparent Mediums?

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Discussion Overview

The discussion centers around the observability of visible light bremsstrahlung when an electron beam interacts with a transparent medium. Participants explore theoretical aspects, practical observations, and the conditions under which such emissions might occur, with a focus on the efficiency and challenges of detecting a continuous spectrum of visible light.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants suggest that bremsstrahlung can produce visible photons, but the efficiency of this process is extremely low, making observation difficult.
  • There is a discussion about the energy levels required for bremsstrahlung to occur, with some indicating that a few eV may be sufficient if the electron beam can penetrate the medium.
  • One participant mentions the visibility of Cerenkov radiation in a nuclear reactor, implying that similar phenomena could be observed with bremsstrahlung in the visible spectrum.
  • Another participant shares a personal experience of observing a glow from an x-ray source, suggesting that bremsstrahlung can indeed be visible under certain conditions.
  • There is a suggestion that bremsstrahlung could be generated safely with a low energy beam in an appropriate transparent medium, challenging the notion of risk associated with observation.

Areas of Agreement / Disagreement

Participants express differing views on the conditions necessary for observing visible light bremsstrahlung, with no consensus on the feasibility or safety of such observations. Some agree that it is theoretically possible, while others emphasize the practical challenges involved.

Contextual Notes

Participants reference specific energy levels and types of radiation (e.g., Cerenkov radiation) without resolving the complexities of how these relate to bremsstrahlung in transparent mediums. The discussion includes assumptions about the efficiency of photon emission and the necessary conditions for observation.

nightvidcole
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Summary: Can one observe visible light bremsstrahlung when an electron beam stops in a transparent medium?

The theoretical form of a bremsstrahlung spectrum is flat at low photon energies. This means that even a high energy electron beam incident on matter should cause the emission of visible photons, albeit with extremely low efficiency. So why is it so hard to observe a continuous spectrum ( and not just line emission) in the visible region from cathode rays in a low pressure gas or a vacuum tube with residual gas?
 
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nightvidcole said:
Summary: Can one observe visible light bremsstrahlung when an electron beam stops in a transparent medium?

flat at low photon energies.
I think that 'low photon energies' means low for X Rays. I was trying to think of how electrons of, say 3eV energy, could be passed through a dense transparent medium and produce visible photons (of that sort of energy). I thought that, to produce bremsstrahlung, you needed an electron beam to penetrate the substance.
 
Yes, you can see it, but I won't recommend looking at it
 
Henryk said:
Yes, you can see it, but I won't recommend looking at it
That would all depend on the energy of the beam. A few eV is enough KE if you can actually get it to penetrate a suitable substance to produce optical frequencies.
 
nightvidcole said:
Summary: Can one observe visible light bremsstrahlung when an electron beam stops in a transparent medium?

The theoretical form of a bremsstrahlung spectrum is flat at low photon energies. This means that even a high energy electron beam incident on matter should cause the emission of visible photons, albeit with extremely low efficiency. So why is it so hard to observe a continuous spectrum ( and not just line emission) in the visible region from cathode rays in a low pressure gas or a vacuum tube with residual gas?

The blue'ish glow that one sees in a water pool of a nuclear reactor is such Cerenkov radiation.

I've also done measurement on the Cerenkov radiation given off when 40 MeV electron bunches slam into a piece of Aerogel to measure the longitudinal bunch length of those electron bunches. Again, that's in the visible range.

There's nothing in the physics that indicates that a Cerenkov radiation can't be in the visible spectrum.

Zz,
 
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sophiecentaur said:
That would all depend on the energy of the beam
No, I've seen it, I accidently looked into the x-ray source when it wasn't blocked. It does glow.
 
Henryk said:
No, I've seen it, I accidently looked into the x-ray source when it wasn't blocked. It does glow.
I was questioning the idea that it would have to be risky (as in your case). I was suggesting that bremsstrahlung could be generated (safely) with a low energy beam in the 'appropriate' transparent medium.
 

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