Gamma rays are often emitted along with alpha or beta particles during radioactive decay. Gamma rays are a radiation hazard for the entire body. They can easily penetrate barriers that can stop alpha and beta particles, such as skin and clothing.
Gamma rays have so much penetrating power that several inches of a dense material like lead, or even a few feet of concrete may be required to stop them. Gamma rays can pass completely through the human body; as they pass through, they can cause ionizations that damage tissue and DNA. Because of their use in medicine, almost everyone has heard of x-rays. X-rays are similar to gamma rays in that they are photons of pure energy.
X-rays and gamma rays have the same basic properties but come from different parts of the atom. X-rays are emitted from processes outside the nucleus, but gamma rays originate inside the nucleus. They also are generally lower in energy and, therefore less penetrating than gamma rays. X-rays can be produced naturally or by machines using electricity. Literally thousands of x-ray machines are used daily in medicine. Computerized tomography, commonly known as a CT or CAT scan, uses special x-ray equipment to make detailed images of bones and soft tissue in the body.
Medical x-rays are the single largest source of man-made radiation exposure. Learn more about radiation sources and doses. X-rays are also used in industry for inspections and process controls. Elements in the periodic table can take on several forms. Uranium decays or breaks down very slowly into other elements including radium and radon.
Learn more about uranium in drinking water. Radium is a radioactive metal that can be found at varying levels throughout Vermont and the entire Earth—in soil, water, rocks, plants and food. Learn more about radium in drinking water.
Radon is a radioactive gas that has no color, smell or taste. Over billions of years, uranium decays into radium, and eventually into radon. Learn more about radon in indoor air and in drinking water. Polonium Po is a radioactive material that occurs naturally at very low concentrations in the environment. How is radioactivity measured?
Radioactivity is a physical, not a biological, phenomenon. Simply stated, the radioactivity of a sample can be measured by counting how many atoms are spontaneously decaying each second.
This can be done with instruments designed to detect the particular type of radiation emitted with each "decay" or disintegration. The actual number of disintegrations per second may be quite large. Scientists have agreed upon common units to use as a form of shorthand. Thus, a curie abbreviated "Ci" and named after Pierre and Marie Curie, the discoverers of radium [87] is simply a shorthand way of writing "37,,, disintegrations per second," the rate of disintegration occurring in 1 gram of radium.
The more modern International System of Measurements SI unit for the same type of measurement is the becquerel abbreviated "Bq" and named after Henri Becquerel, the discoverer of radioactivity , which is simply a shorthand for "1 disintegration per second. Being unstable does not lead an atomic nucleus to emit radiation immediately. Share sensitive information only on official, secure websites. JavaScript appears to be disabled on this computer. Please click here to see any active alerts.
Radioactive decay is the emission of energy in the form of ionizing radiation ionizing radiation Radiation with so much energy it can knock electrons out of atoms. Ionizing radiation can affect the atoms in living things, so it poses a health risk by damaging tissue and DNA in genes. The ionizing radiation that is emitted can include alpha particles alpha particles A form of particulate ionizing radiation made up of two neutrons and two protons. Alpha particles pose no direct or external radiation threat; however, they can pose a serious health threat if ingested or inhaled.
Some beta particles are capable of penetrating the skin and causing damage such as skin burns. Beta-emitters are most hazardous when they are inhaled or swallowed.
Gamma rays can pass completely through the human body; as they pass through, they can cause damage to tissue and DNA.
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