Why only gamma radiation from nuclear transitions?

In summary, gamma radiation is emitted only from radioactive elements that decay by emitting gamma rays. There is a huge gap in the number of isotopes that emit gamma radiation, and because of this there are few examples that are familiar to most people.
  • #1
PhysicoRaj
Gold Member
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Why only gamma radiation...?

All the radioactive elements emit either alpha, beta, never both and maybe sometimes gamma with these. But why do they emit gamma rays only? Why not X-Rays?
 
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  • #2


In principle there is no difference between gamma- and X-rays. Both are "just" electromagnetic radiation. The convention is to call them gamma when they come from the nucleus, and x-rays when they come from electronic transitions.
 
  • #3


PhysicoRaj said:
All the radioactive elements emit either alpha, beta, never both

I'd not be surprised if that is generally the case because a nucleus is unstable either beause it is 'neutron heavy' and is prone to emit a beta (a beta is usually from a proton decaying, mediated by the weak force), or 'proton heavy' in which case it will emit a positron or 'it could reduce' the relative p:n ratio by lumping out an alpha.

But I'm pretty sure there are isotopes that emit all types. U238 I seem to recall decays by alpha, double beta and fission.
 
  • #4


Ta-180 is predicted to decay via gamma emission. However, the half life is about 1015 years, and it has not been observed. There are other gamma-only states, but they typically have half-lives that are milliseconds or smaller. Since there is a huge gap, there aren't many isotopes one is likely to be familiar with.
 
  • #5


Thank you guys.
 
  • #6


Just for curiosities sake, there are some freaky low energy nuclear transitions like this: http://www.thorium.at/?page_id=4 . There is an isomer of Th-229 with an energy only 7.6 eV above the ground state, so when this state relaxes it emits a "gamma ray" of only UV wavelength.
 
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  • #7


Historically, the term x-ray sometimes applied only to photons from atomic level transitions (up to about 120 keV), and gammas only from nuclear transitions. Now, the term x rays seems to apply to both atomic and nuclear photons.

The decay of beryllium-7 to lithium-7 is a very interesting nuclear decay, in that it emits only an atomic x-ray and a neutrino. Be-7 decays by capturing an electron from the atomic k-shell, and emitting a neutrino. It emits no nuclear gammas and no charged particles (alpha or beta). The x-rays come from outer atomic electons cascading down to fill the k-shell vacancy.
 

FAQ: Why only gamma radiation from nuclear transitions?

What is gamma radiation?

Gamma radiation is a form of electromagnetic radiation that has a very high frequency and short wavelength. It is a type of ionizing radiation that is emitted by radioactive substances and nuclear reactions.

Why is gamma radiation the only type of radiation used in cancer treatment?

Gamma radiation is the only type of radiation used in cancer treatment because it has the ability to penetrate deep into tissues and target cancer cells specifically. This makes it an effective tool for destroying cancer cells while minimizing damage to surrounding healthy tissues.

What makes gamma radiation more dangerous than other types of radiation?

Gamma radiation is more dangerous than other types of radiation because it has a higher energy and can penetrate deeper into the body. This means that it can cause more damage to cells and tissues, leading to potential health risks such as cancer and genetic mutations.

How is gamma radiation produced?

Gamma radiation is produced through nuclear reactions, such as radioactive decay or nuclear fission. It can also be produced artificially through processes like particle accelerators and nuclear reactors.

What are the uses of gamma radiation besides cancer treatment?

Besides cancer treatment, gamma radiation has many other uses in various industries and fields. It is used in sterilization processes to kill harmful bacteria and viruses, in industrial radiography for quality control and testing, and in food irradiation to extend shelf life and eliminate harmful bacteria. It is also used in scientific research and medical imaging techniques such as PET scans.

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