以下附上部份原文資訊 Alpha radiation consists of heavy, positively charged particles containing two protons and two neutrons. Alpha particles are usually emitted from isotopes with an atomic number of 82, such as uranium or plutonium. Due to their large size, alpha particles have limited penetrating power. Fine obstacles such as cloth or human skin can usually stop them from penetrating into the body, and they represent a small risk to external exposure due to their limited penetration. If they somehow are internalized, then alpha particles can cause significant cellular damage within their immediate proximity.
Beta radiation consists of electrons, which are small, light, negatively charged particles (about 1/2000 the mass of a neutron or proton). They can travel only a short finite distance in tissue, depending on their energy. Exposure to beta particles is common in many radiation accidents. Radioactive iodine, released in nuclear plant accidents, is the best known member of this group. Plastic layers and clothing can stop most beta particles, and their penetration is measured to be a few millimeters. A large quantum of energy to the basal stratum of the skin can cause a burn that is similar to a thermal burn and is treated as such.
Gamma rays and x-rays (both photons) are similar. Gamma rays are uncharged electromagnetic radiation discharged from a nucleus as a wave or photons of energy. X-rays are the product of abrupt mechanical deceleration of electrons striking a heavy target such as tungsten. Gamma and x-rays have similar properties, i.e., no charge and no mass, just energy. Both travel easily through matter, sometimes called penetrating radiation, and are the principal type of radiation to cause total-body exposure. If the energy of gamma rays and x-rays is the same, then their biological effects will be the same.