Positron emission is a special kind of natural process where an atom's nucleus changes. It's also called beta plus decay. In this process, a proton inside an atom transforms into a neutron. When this happens, the atom releases a tiny particle called a positron and an electron neutrino. The weak force, one of the fundamental forces of nature, makes this transformation possible.
A positron is like an electron but with a positive charge, and it's a type of beta particle. This decay usually happens in atoms that have too many protons, making them unstable. As a result, the original atom changes into a different chemical element with one less proton, for example, Magnesium-23 can transform into Sodium-23.
This type of decay is quite rare in nature here on Earth. However, it can occur in some special radioactive atoms, like a very small amount of potassium-40. Scientists Frédéric and Irène Joliot-Curie first discovered positron emission in a lab in 1934, calling it "artificial radioactivity." They created a new element that then released positrons, earning them a Nobel Prize.
Many of the atoms that undergo positron emission, such as carbon-11, nitrogen-13, oxygen-15, and fluorine-18, are very important. These special atoms are used in medical imaging, specifically for a technique called Positron Emission Tomography, or PET scans, to help doctors see inside the body.
