Electron and proton penetration

In summary, at the same energy, an electron is more likely to penetrate further into matter compared to a proton. However, at the same speed, a proton will penetrate much deeper due to its higher energy and mass. This can be explained using the Bethe-Bloch formula, where the energy loss per length is similar for both particles, but the proton has a higher energy. Further comparison between electron and proton energies for a given speed can be done using the formula ##E=\gamma m c^2## and knowing the approximate mass ratio between the two particles.
  • #1
adamworth
23
0

Homework Statement



Which, of an electron and a proton (of a few Mev), is more likely to penetrate further into matter if they both have:

a) The same energy
b) The same speed

Homework Equations



Bethe-Bloch formula.

Total stopping power = collision loss + radiation loss
(de/dx)t = (de/dx)c + (de/dx)r

The Attempt at a Solution



a) Electron will penetrate further. If both have the same energy, collision loss is less for electrons as (de/dx)c = 1/v2

b) Both will penetrate the same distance. If both have the same speed, collision loss is the same for both electrons and protons. Radiation loss is minimal as this only comes into effect for higher energies (many Mev).
 
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  • #2
Bremsstrahlung could be important for electrons.

"The same speed" doesn't allow both electrons and protons to have a few MeV, it is unclear which particle is supposed to have an energy in this range.
 
  • #3
I've attached the question below. I think it means electrons of a few MeV. My reasoning is that Bremsstrahlung doesn't have much of an effect at a few MeV, so both the electron and proton will penetrate the same distance. But I'm not sure...
ndVaPQv.jpg
 

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  • ndVaPQv.jpg
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  • #4
At the same speed, you have to compare electrons at a few MeV with protons at a few GeV. It should be clear what travels faster, even if you neglect Bremsstrahlung.
 
  • #5
So you believe the proton will penetrate deeper? How do I explain this in terms of the Bethe-Bloch formula?

mfb said:
At the same speed, you have to compare electrons at a few MeV with protons at a few GeV. It should be clear what travels faster, even if you neglect Bremsstrahlung.
 
  • #6
The proton will penetrate much deeper. Its energy loss per length will be similar but it has much more energy.
 
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  • #7
Ok thanks for the help. Is there any particular resource where you can compare electron and proton energies for a given speed?
 
  • #8
##E=\gamma m c^2##, a given speed means a given ##\gamma## and you should know the approximate proton to electron mass ratio.
 

1. What is electron and proton penetration?

Electron and proton penetration refers to the ability of these subatomic particles to pass through materials or barriers, typically due to their small size and high energy levels. This phenomenon is important in various fields such as nuclear physics, radiation therapy, and materials science.

2. How does the penetration ability of electrons and protons differ?

Electrons, being much smaller than protons, have a higher probability of penetrating materials due to their wave-like nature and lack of electric charge. Protons, on the other hand, have a positive charge and are relatively larger, so they can be stopped or slowed down by the electric fields of atomic nuclei.

3. What factors affect the penetration of electrons and protons?

The penetration ability of electrons and protons depends on their energy level, the density and composition of the material they are passing through, and the distance they travel. Higher energy levels and lower density materials generally result in greater penetration.

4. How is the penetration of electrons and protons measured?

The penetration of electrons and protons can be measured through techniques such as electron microscopy, particle accelerators, and radiation detectors. These methods involve measuring the interactions of these particles with the material they are passing through.

5. What are the applications of understanding electron and proton penetration?

Understanding the penetration ability of electrons and protons is crucial in fields such as nuclear physics, medical imaging and therapy, materials science, and radiation protection. It allows for the development of new technologies and techniques, and helps ensure the safe and effective use of these particles in various applications.

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