<unk>  (or<unk> , including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. The particles generally travel at a speed that is 99% of that of light, and the electromagnetic waves are on the high-energy portion of the electromagnetic spectrum. Gamma rays, X-rays, and the higher energy ultraviolet part of the electromagnetic spectrum are<unk> , whereas the lower energy ultraviolet, visible light, nearly all types of laser light, infrared, microwaves, and radio waves are non-ionizing radiation. The boundary between<unk>  and non-ionizing radiation in the ultraviolet area is not sharply defined because different molecules and atoms ionize at different energies. The energy of<unk>  starts between 10 electronvolts (eV) and 33 eV and extends further up. Typical<unk>  subatomic particles include alpha particles, beta particles, and neutrons. These are typically created by radioactive decay, and almost all are energetic enough to ionize. Secondary cosmic particles produced after cosmic rays interact with Earth's atmosphere, including muons, mesons, and positrons. Cosmic rays may also produce radioisotopes on Earth (for example, carbon-14), which in turn decay and emit<unk> . Cosmic rays and the decay of radioactive isotopes are the primary sources of natural<unk>  on Earth, contributing to background radiation.<unk>  is also generated artificially by X-ray tubes, particle accelerators, and nuclear fission.<unk>  is not detectable by human senses, so instruments such as Geiger counters must be used to detect and measure it. However, very high energy particles can produce visible light, such as in Cherenkov radiation.<unk>  is used in a wide variety of fields such as medicine, nuclear power, research, and industrial manufacturing, but presents a health hazard if proper measures against excessive exposure are not taken. Exposure to<unk>  causes cell damage to living tissue and organ damage. In high acute doses, it will result in radiation burns and radiation sickness, and lower level doses over a protracted time can cause cancer. The International Commission on Radiological Protection (ICRP) issues guidance on<unk>  protection, and the effects of dose uptake on human health.
Ionizing radiation
Irradiation
Radiation
Co-carcinogen
Immunologic adjuvant
Food irradiation
Carcinogen
Radiosensitizer