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Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered radioactive. Three of the most common types of decay are alpha, beta, and gamma decay.
Radiation is often categorized as either ionizing or non-ionizing depending on the energy of the radiated particles. Ionizing radiation carries more than 10 electron volts (eV), which is enough to ionize atoms and molecules and break chemical bonds. This is an important distinction due to the large difference in harmfulness to living organisms.
The unit of radioactivity from the System International of units (SI system) is the becquerel (Bq) defined as the radioactive decay or disintegration of one radionuclide per second. Radioactivity is a measure of the total, local rate of radionuclides decaying per unit time and is dependent upon the total number of atoms, decay constants , and ...
Surface contamination may either be fixed or "free". In the case of fixed contamination, the radioactive material cannot by definition be spread, but its radiation is still measurable. In the case of free contamination, there is the hazard of contamination spread to other surfaces such as skin or clothing, or entrainment in the air.
Again, a key feature of using radioactivity in life science applications is that it is a quantitative technique, so PET/SPECT not only reveals where a radiolabelled molecule is but how much is there. Radiobiology (also known as radiation biology) is a field of clinical and basic medical sciences that involves the study of the action of ...
In the context of radioactivity, activity or total activity (symbol A) is a physical quantity defined as the number of radioactive transformations per second that occur in a particular radionuclide. [3] The unit of activity is the becquerel (symbol Bq), which is defined equivalent to reciprocal seconds (symbol s −1).
The radiation chemistry controls much of radiation biology as radiation has an effect on living things at the molecular scale. To explain it another way, the radiation alters the biochemicals within an organism, the alteration of the bio-molecules then changes the chemistry which occurs within the organism; this change in chemistry then can ...
Induced radioactivity, also called artificial radioactivity or man-made radioactivity, is the process of using radiation to make a previously stable material radioactive. [1] The husband-and-wife team of Irène Joliot-Curie and Frédéric Joliot-Curie discovered induced radioactivity in 1934, and they shared the 1935 Nobel Prize in Chemistry ...