What is radiation?
There is nothing new or mysterious about radiation. It has always been a part of our natural environment. We are constantly exposed to radiation from the sun and outer space. Naturally occurring radioactive materials are present in the earth around us, in the buildings we live and work in, and in the food and water we consume. There are radioactive gases in the air we breathe, and our bodies themselves are radioactive to some degree. The nuclear power industry is a small contributor to the average radiation exposure. The levels of this natural radiation vary greatly from place to place. Persons living in Denver, Colorado, for example, receive double the amount of natural radiation that we receive in Virginia. That s primarily because of Denver s higher altitude. We are also exposed to sources of man-made radiation. For more than half a century, doctors and scientists have used X-rays and other forms of penetrating radiation.
Radiation is energy that comes from a source and travels through space and may be able to penetrate various materials. Light, radio, and microwaves are types of radiation that are called nonionizing. The kind of radiation discussed in this document is called ionizing radiation because it can produce charged particles (ions) in matter. Ionizing radiation is produced by unstable atoms. Unstable atoms differ from stable atoms because unstable atoms have an excess of energy or mass or both. Radiation can also be produced by high-voltage devices (e.g., x-ray machines). Atoms with unstable nuclei are said to be radioactive. In order to reach stability, these atoms give off, or emit, the excess energy or mass. These emissions are called radiation. The kinds of radiation are electromagnetic (like light) and particulate (i.e., mass given off with the energy of motion). Gamma radiation and x rays are examples of electromagnetic radiation.
Radiation is energy that travels in the form of waves or high speed particles. When we hear the word ‘ radiation,’ we generally think of nuclear power plants, nuclear weapons, or radiation treatments for cancer. We would also be correct to add ‘microwaves, radar, electrical power lines, cellular phones, and sunshine’ to the list. There are many different types of radiation that have a range of energy forming an electromagnetic spectrum. However, when you see the word ‘radiation’ on this web site, we are referring to the types of radiation used in nuclear power, nuclear weapons, and medicine. These types of radiation have enough energy to break chemical bonds in molecules or remove tightly bound electrons from atoms, thus creating charged molecules or atoms (ions). These types of radiation are referred to as ‘ionizing radiation.
We live in a sea of radiation. There are many different types of radiation, some of which are visible light, ultraviolet rays from the sun, infrared from a heat lamp, microwaves, radio waves and ionizing radiation. Radiation is said to be ionizing if it has sufficient energy to displace one or more of the electrons that are part of an atom. This creates an electrically charged atom known as an ion. Common examples of ionizing radiation are x rays, which are generated by machines, and gamma rays, which are emitted by radioactive materials. Others include alpha and beta rays, which are also emitted from radioactive materials, and neutrons, which are emitted during the splitting (fission) of atoms in a nuclear reactor.
Radiation is energy that travels in waves. It includes visible light, ultraviolet light, radio waves and other forms, including particles. Each type of radiation has different properties. Non-ionizing radiation can shake or move molecules. Ionizing radiation can break molecular bonds, causing unpredictable chemical reactions. Ionizing radiation includes not only energy waves but particles as well. Humans cannot see, feel, taste, smell or hear ionizing radiation. Unavoidable exposure to ionizing radiation comes from cosmic rays and some natural material. Human exposure to natural radiation is responsible for a certain number of mutations and cancers. Additional exposure above natural background radiation is cause for concern since it may result in otherwise preventable disease. WHERE DOES IONIZING RADIATION COME FROM? Ionizing radiation is matter or energy that is given off by the nucleus of an unstable atom in the process of decaying and reaching a stable (ground) state.
