Teaching the Penetrating Powers of Radiation: Alpha, Beta, and Gamma

In summary, Pavadrin explains that the alpha particle has the highest penetrating ability and the gamma the lowest. He also explains that gamma rays can be absorbed or scattered. Food irradiation usually uses gamma radiation, so the food atoms/molecules are only ionized. Finally, Pavadrin provides a summary of the content.
  • #1
pavadrin
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Hey
Recently I have been studied for a physics test on Nuclear Technology. A question I came across asked me to explain the difference between the penetrating ability of the three different types of radiation, alpha, beta and gamma and explain why. I know that gamma has the highest penetrating ability and alpha the smallest, but I do not know the reasons behind this. Also, how come when food becomes irradiated it does not become radioactive? Alpha particles are stopped by a piece of paper. Would this piece of paper become radioactive? Why or why not?
Many thanks,
Pavadrin
 
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  • #2
The alpha particle has a 2+ charge, beta has 1- charge, and the gamma is neutral (no charge). All three particles primarily interact with atomic electrons in the matter through which they pass, and they ionize those atoms. Also the alpha is massive compared to the beta and gamma, and the beta is more massive than the gamma, so more momentum is transferred from the heavier particles to atoms encountered along the path.

The interaction is strongest for the alpha particle with the 2+ charge, and weakest for the gamma with no charge.

Electrons can interact by the brehmsstrahlung (braking radition) reaction when they interact with the nuclear electric field.

Gamma rays can be absorbed (photoelectric effect or pair production) or scattered (Compton effect). In the photoelectric effect, the gamma interacts with an atomic electron an is completely absorbed. In pair production, the gamma interacts with the nucleus and forms a positron-electron pair. The threshold for pair production is 1.022 MeV or twice the rest mass of the electron.

Food irradiation is usually accomplished with gamma radiation, so the food atoms/molecules are only ionized. The nuclei of the food molelcules are not affect, i.e. no radioactivity is induced.

Activation (making something radioactive) requires the use of neutrons which interact (are absorbed) by nuclei, which increases the nuclear mass by 1 amu, and the resulting nuclei then decay by beta decay. Some nuclei, like B-10 experience alpha decay upon absorption of a neutron, otherwise alpha decay occurs in heavier nuclear starting with isotopes of Bi-211, although Po has several lighter isotopes, which undergo alpha decay.

For future reference - http://www.nndc.bnl.gov/nudat2/
 
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Likes Marcy
  • #3
thank for your help Astronuc, greatly appricated
 
  • #4
in my book its speaks of a beta particle having a 1+ charge and a 1- charge. What is the difference between these beta particles? I know that the 1- charge particle is the deacy of a neutron into a proton and an electron, but as for the other one, it is not explanied in the book.
many thanks
 
  • #5
pavadrin said:
in my book its speaks of a beta particle having a 1+ charge and a 1- charge. What is the difference between these beta particles? I know that the 1- charge particle is the deacy of a neutron into a proton and an electron, but as for the other one, it is not explanied in the book.
many thanks
Beta radiation is made of electron or its antiparticle, the positron. (you know that there is beta decay as well as inverse beta decay).
So when they give a charge of +e, they are referring to the positron.
 
  • #6
Just further to what nrqed said a couple of examples of beta decay;

Beta+ Decay:
[tex]p \rightarrow n + \upsilon_{e} + e^{+}[/tex]

Beta- Decay;
[tex]n \rightarrow p + \overline{\upsilon_{e}} + e^{-}[/tex]

I was going to draw Feynman diagrams but then I realized PF doesn't support them in latex :cry:
 
  • #7
Hootenanny said:
Just further to what nrqed said a couple of examples of beta decay;

Beta+ Decay:
[tex]p \rightarrow n + \upsilon_{e} + e^{+}[/tex]

Beta- Decay;
[tex]n \rightarrow p + \overline{\upsilon_{e}} + e^{-}[/tex]

I was going to draw Feynman diagrams but then I realized PF doesn't support them in latex :cry:
Hi Hoot.

How does one draw Feynman diagrams directly in Latex?
It must involve some extra package, Any link to the package/tutorial?

Thanks

Patrick
 
  • #8
nrqed said:
Hi Hoot.

How does one draw Feynman diagrams directly in Latex?
It must involve some extra package, Any link to the package/tutorial?

Thanks

Patrick
Hey Patrick,

Yes, there is although I've only just started playing with it, it doesn't seem to be fully operational yet:grumpy: . I'm going to ask in the Latex tutorial if someone can help me out. Anyway the package is called feynmf and is located here http://tug.ctan.org/tex-archive/macros/latex/contrib/feynmf/
 
  • #9
Any ideas on how to teach the penetrating powers of alpha, beta and gamma radiation in the absenc of radiation sources?
 

1. What are the different types of radiation?

The three main types of radiation are alpha, beta, and gamma. Alpha radiation consists of particles called alpha particles, which are made up of two protons and two neutrons. Beta radiation consists of particles called beta particles, which are either electrons or positrons. Gamma radiation is a type of electromagnetic radiation and does not consist of particles.

2. How are alpha, beta, and gamma radiation different?

Alpha radiation is the least penetrating type of radiation and can be stopped by a piece of paper. Beta radiation is more penetrating and can be stopped by a thin sheet of metal. Gamma radiation is the most penetrating and requires several inches of lead or several feet of concrete to stop it.

3. What are the potential health effects of exposure to radiation?

Exposure to radiation can cause damage to cells and tissues, leading to health effects such as skin burns, radiation sickness, and an increased risk of developing certain types of cancer. The severity of the health effects depends on the type and amount of radiation exposure.

4. How is radiation measured?

Radiation is measured in units called sieverts (Sv) or millisieverts (mSv). The level of radiation exposure is also measured in terms of the absorbed dose, which is measured in units called grays (Gy) or millisieverts (mGy). The absorbed dose takes into account the type of radiation and its energy, as well as the type of tissue exposed.

5. How can exposure to radiation be reduced?

Exposure to radiation can be reduced by limiting the amount of time spent near a source of radiation, increasing the distance from the source, and using shielding materials such as lead or concrete. It is also important to follow safety guidelines and regulations when working with or around sources of radiation.

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