# Anti-matter is not as rare as you might think 😇

## I have an anti-matter emitting source in my lab

2 min readNov 17, 2022

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Yesterday I was discussing in the lab how a γ-ray source emits γ-rays. It contains unstable nuclei that want to get rid of their excess energy. They emit energy via particles such as electrons, γ-rays, protons, neutrons, etc. If you have noticed, all these are ordinary matter particles.

What if I tell you that unstable nuclei can also emit particles made up of a different kind of matter?🤨

What different kind of matter? I hear you ask. 🤔

Let us take an example.

An electron is a fundamental particle having a negative electric charge and a mass of 0.511 keV/c².

If you are unfamiliar with keV and MeV, read this easy-to-understand story about them. 👇

What if I tell you that there exists a particle with the same amount of charge as the electron, except it is a positive charge and the exactly same mass. 😦

Yes, the exact same mass but a positive charge.

This particle is called a positron.

What makes the positron a different kind of matter?

# Positrons and electrons literally annihilate each other if they come in contact.

Meaning, boom💥

Several unstable nuclei emit positrons.

One of the most common radioactive nuclei that emit positron is Sodium-22.

Sodium has an atomic number of 11. This means there are 11 protons inside its nucleus.

The mass number of Sodium-22 is 22. This is the total number of protons and neutrons inside its nucleus.

So, a nucleus of Sodium-22 has 11 protons and 11 neutrons.

Since protons are positively charged, they repel each other. Neutrons are neutral and hence, don't repel anything. However, neutrons attract other neutrons and protons by a strong force.

The critical point is that the nucleus of the Sodium-22 atom has an excess number of protons. It is unstable, with 11 protons and 11 neutrons.

Now comes a fascinating thing.

One proton in the nucleus decides to emit a positron and transforms itself into a neutron.😦

And hence a positron is emitted.

But how does this happen?

That’s the story for another day.

If you have enough Sodium-22 nuclei, you can have a source of positrons. This is what we have in our lab.

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