Positron Emission: Exploring the Science Behind It

In summary, the law of conservation of energy states that the total mass of a nucleus must always be the same as the total mass of the individual particles that make up the nucleus. The difference between the total mass of the nucleus and the total mass of the individual particles is called nuclear binding energy. This binding energy is what provides the energy for both fusion and fission.
  • #1
cylinder
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I've been wondering about positron emission. If a neutron has more mass than a proton, how can a proton turn into a neutron by releasing a particle with mass?
[PLAIN]http://img37.imageshack.us/img37/654/positronemission.gif [Broken]
(source:http://en.wikipedia.org/wiki/Positron_emission)
Doesn't this violate the law of conservation of energy? Isn't Boron-11 heavier than Carbon-11?
 
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  • #2
cylinder said:
Isn't Boron-11 heavier than Carbon-11?

Look them up. :smile:

http://www.nist.gov/physlab/data/comp.cfm [Broken]

For C you need to use the "All isotopes" option.
 
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  • #3
But... Doesn't Boron have 6 neutrons and 5 protons, where Carbon has 5 neutrons and 6 protons? What am I missing here? Apologies, but my knowledge of nuclear physics is elementary, at best.
 
  • #4
Cylinder, jtbell gave you some excellent advice. Look them up.
 
  • #5
Yes, I looked them up before I posted that. I'm sorry, I was just stating that I am confused about something else now: it looks like the masses of the nucleons don't add linearly. I understand if my new question is a bit off topic. Should I start a new thread?
 
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  • #7
cylinder said:
Yes, I looked them up before I posted that. I'm sorry, I was just stating that I am confused about something else now: it looks like the masses of the nucleons don't add linearly.

The concept of nuclear binding energy is the piece you seem to be missing:

http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin.html

has a pretty good overview for this and the basics of nuclear mass and how it relates to nucleons.

Essentially, this binding energy (mass) difference is the source of the energy for both fusion and fission.
 
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The total mass of a nucleus is LESS than the total mass of the individual particles that make up the nucleus if they were not bound, because of nuclear binding energy.
 
  • #9

1. What is positron emission?

Positron emission is a type of radioactive decay in which a proton in the nucleus of an atom is converted into a neutron, releasing a positron (a positively charged particle) and a neutrino.

2. How is positron emission used in science?

Positron emission is used in a variety of scientific applications, including medical imaging (positron emission tomography or PET scans), materials science, and nuclear physics research.

3. What is the significance of positron emission in understanding the structure of matter?

Positron emission is significant in understanding the structure of matter because it provides insight into the behavior of subatomic particles and the forces that govern them. It also allows scientists to study the properties and interactions of antimatter.

4. How is positron emission different from other types of radioactive decay?

Positron emission is different from other types of radioactive decay (such as alpha and beta decay) because it involves the conversion of a proton into a neutron, rather than the release of a particle from the nucleus. It also results in the creation of a positron, which is the antiparticle of an electron.

5. Can positron emission be controlled or harnessed for practical purposes?

Positron emission can be controlled and harnessed for practical purposes, such as in medical imaging and radiation therapy. However, it is also a natural process that occurs in many radioactive elements and cannot be artificially induced or stopped.

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