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Distances of radiaition


KlausZahn
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I look at the different ranges that have alpha radiation, beta radiation and gamma radiation in the air. Alpha radiation has the smallest distance, gamma radiation the longest. Unfortunately, I do not know why. Can someone explain the different ranges?
Thanks for your answers

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40 minutes ago, KlausZahn said:

I look at the different ranges that have alpha radiation, beta radiation and gamma radiation in the air. Alpha radiation has the smallest distance, gamma radiation the longest. Unfortunately, I do not know why. Can someone explain the different ranges?
Thanks for your answers

It's really very simple.

Alpha particles are really helium nuclei and are double positively charged.

Thus they have by far the largest particles of the three (by many thousands of times compared to beta particles)

Furthermore the double [positive charge makes them attractive to other charged particles.

Beta particles are electrons and therfore carry a single negative charge, and as noted are much smaller than alpha particles.

Gamma 'particles'  are really photons which are very small indeed and have no charge or mass.
So they travel at the speed of light.

 

As a result of these facts the speeds are gamma >>> beta > alpha.

If you send a stream of particles through air the chances of them hitting something decrease with increasing speed and decreasing size.

 

http://chemed.chem.purdue.edu/genchem/history/rutherford.html

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6 hours ago, tinkerer said:

A further question: Does the Inverse Square Law for Intensity apply for Alpha and Beta radiation?

 

5 hours ago, StringJunky said:

Yes, there's no difference.

 

The transmission medium original question was air.

Further alpha and beta rays are both charged and particulate.

The particulate part says that it depends upon the nature of the source and the particle density.

The charge says that there is interaction with airborn particles.

 

In fact transmission through a medium usually follows an exponential decay type law.
This also applies to EM radiation, but the coefficients are such that air is virtually transparent to gamma rays, over distances measured in less than hundreds of kilometers.

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On 12/8/2018 at 12:59 PM, studiot said:

It's really very simple.

Alpha particles are really helium nuclei and are double positively charged.

Thus they have by far the largest particles of the three (by many thousands of times compared to beta particles)

Furthermore the double [positive charge makes them attractive to other charged particles.

Beta particles are electrons and therfore carry a single negative charge, and as noted are much smaller than alpha particles.

Gamma 'particles'  are really photons which are very small indeed and have no charge or mass.
So they travel at the speed of light.

 

As a result of these facts the speeds are gamma >>> beta > alpha.

If you send a stream of particles through air the chances of them hitting something decrease with increasing speed and decreasing size.

 

It's not quite that simple, though. Neutrinos travel (slightly) slower than photons but are far more penetrating because they don't interact the same way. You have to look at the interaction probability as well.

Alphas are more likely to interact owing to their larger charge. They will ionize surrounding atoms, which causes them to lose energy and slow down. Neutrons will tend to penetrate better than protons, because even though they have roughly the same mass, the neutron has no charge.

1 hour ago, studiot said:

In fact transmission through a medium usually follows an exponential decay type law.

This also applies to EM radiation, but the coefficients are such that air is virtually transparent to gamma rays, over distances measured in less than hundreds of kilometers.

Alphas don't. They have a pretty well-defined penetration depth.  

"The range of alphas of a given energy is a fairly unique quantity in a specific absorber material."
https://sciencedemonstrations.fas.harvard.edu/presentations/α-β-γ-penetration-and-shielding

 

There's a plot here of what the alpha count typically looks like with distance.

https://physics.stackexchange.com/questions/308359/does-alpha-radiation-penetration-depth-decrease-exponentionaly-with-distance/308428#308428

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49 minutes ago, studiot said:

 

 

The transmission medium original question was air.

Further alpha and beta rays are both charged and particulate.

The particulate part says that it depends upon the nature of the source and the particle density.

The charge says that there is interaction with airborn particles.

 

In fact transmission through a medium usually follows an exponential decay type law.
This also applies to EM radiation, but the coefficients are such that air is virtually transparent to gamma rays, over distances measured in less than hundreds of kilometers.

OK. Noted. Cheers.

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