Two classes of ionizing radiation

Electromagnetic waves:

• X-Rays
• Gamma Rays

Particles:

• Neutrons
• Electrons, Beta Rays
• Protons
• Alphas
• Heavy Ions

X-rays and Gamma rays are energy transmitted in a wave without the movement of any material. X-rays and gammas differ in their origin. X-rays are emitted by an electrical device. Gamma rays are produced by unstable or radioactive isotopes.

Neutrons are uncharged particles. They are one of the particles that make up an atomic nucleus. Because they have no charge, they are very penetrating.

Electrons are small negatively charged particles also found in all normal atoms. They are about 1800 times smaller than neutrons. Electrons are often given off when radioactive materials break down, in which case they are called beta rays.

Protons are positively charged particles found in every atomic nucleus. Their mass is close to that of a neutron. Protons are the chief constituent of primary cosmic rays

Alpha particles are identical to the nuclei of helium atoms, composed of two protons and two neutrons. They are positively charged, and are usually emitted when heavy radioactive isotopes, such as uranium, break down.

Heavy ions, larger than alpha particles, are the nuclei of any atoms that have been stripped of their electrons. They move at great speeds and have large amounts of energy. They are common in outer space, and may also be produced by special types of accelerators.