Three Types of Radioactive Decay
There are three main types of radiation:- Alpha radiation
- Beta radiation
- Gamma radiation
Alpha Decay
- The reason alpha decay occurs is because the nucleus has
too many protons which cause excessive repulsion. In an attempt to reduce
the repulsion, a Helium nucleus is emitted. The way it works is that the
Helium nuclei are in constant collision with the walls of the nucleus and
because of its energy and mass, there exists a nonzero probability of transmission.
That is, an alpha particle (Helium nucleus) will tunnel out of the nucleus.
Here is an example of alpha emission with americium-241:
Alpha Decay of Americium-241 to Neptunium-237. Adapted from Alpha Decay.
Beta Decay
- Beta decay occurs when the neutron to proton ratio
is too great in the nucleus and causes instability. In basic beta decay,
a neutron is turned into a proton and an electron. The electron is then
emitted. Here's a diagram of beta decay with hydrogen-3:
Alpha Decay of Hydrogen-3 to Helium-3. Adapted from Stability of Nuclei.
Positron Decay of Carbon-11 to Boron-11. Adapted from Types of Radioactivity.
Electron Capture of Beryllium-7. It decays to Lithium-7. Adapted from Electron Capture.
Gamma Decay
- Gamma decay occurs because the nucleus is at too
high an energy. The nucleus falls down to a lower energy state and, in
the process, emits a high energy photon known as a gamma particle. Here's
a diagram of gamma decay with helium-3:
Gamma Decay of Helium-3
