Positron emission (Beta + decay)

In summary, β+ decay occurs when a proton in a nucleus decays into a neutron, releasing energy in the process. This happens when the mass of the final nucleus is less than the initial nucleus and there is enough energy to facilitate the decay. This process is not as common as β- decay, as it requires specific conditions in the nucleus.
  • #1
OJFord
29
0
Why does β+ decay occur?

If protons are stable and all baryons eventually decay to protons, then how is it that protons can 'decay' to a neutron?

What causes this to happen?
(I assume it isn't as frequent as β- decay, or up and down quarks would be coming and going constantly, and we'd be inundated by electron neutrinos and electrons)
 
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  • #2
Free protons do not undergo β+ decay because a neutron has more mass than a proton.

However, protons in a nucleus can undergo β+ decay if the mass of the final nucleus is less than the mass of the initial nucleus, so that energy can be released. In effect, the difference in the binding energies of the two nuclei provides the energy needed to make the decay "go".
 

Related to Positron emission (Beta + decay)

What is positron emission (Beta + decay)?

Positron emission, also known as Beta + decay, is a type of radioactive decay in which a proton in the nucleus of an atom is converted into a neutron, and a positron (a positively charged particle) is emitted. This results in the atomic number decreasing by one, while the mass number remains the same.

What is the difference between positron emission and electron capture?

Both positron emission and electron capture are types of radioactive decay that involve a proton being converted into a neutron. The main difference is that in positron emission, a positron is emitted from the nucleus, while in electron capture, an electron from the surrounding electron cloud is absorbed into the nucleus. This results in a decrease in the atomic number in both cases, but electron capture also results in a decrease in the mass number.

What types of atoms undergo positron emission?

Positron emission can occur in any atom that has an excess of protons in its nucleus, making it unstable. This includes elements such as carbon, potassium, and fluorine. However, it is most commonly observed in isotopes of light elements such as boron, carbon, and nitrogen.

How is positron emission used in medical imaging?

Positron emission is commonly used in a medical imaging technique called positron emission tomography (PET). In this technique, a radioactive substance that undergoes positron emission is injected into the body. As the positrons collide with electrons in the body, they produce gamma rays that can be detected by a PET scanner. This allows for the creation of 3D images of the body's internal structures and functions.

What are the potential applications of positron emission in other fields?

Besides its use in medical imaging, positron emission has potential applications in other fields such as materials science, environmental monitoring, and energy production. For example, positron annihilation spectroscopy can be used to study the structure and properties of materials, while positron emission can be used to trace the movement of pollutants in the environment. In addition, positron emission can be harnessed to produce energy in the form of positron-electron annihilation reactions.

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