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Radiobiology (also known as radiation biology) is a field of clinical and basic medical sciences that involves the study of the action of radioactivity on biological systems. The controlled action of deleterious radioactivity on living systems is the basis of radiation therapy.
Tritium (from Ancient Greek τρίτος (trítos) 'third') or hydrogen-3 (symbol T or 3 H) is a rare and radioactive isotope of hydrogen with a half-life of ~12.3 years. The tritium nucleus (t, sometimes called a triton) contains one proton and two neutrons, whereas the nucleus of the common isotope hydrogen-1 (protium) contains one proton and no neutrons, and that of non-radioactive hydrogen ...
For example, carbon-14, a radioactive nuclide with a half-life of only 5700(30) years, [27] is constantly produced in Earth's upper atmosphere due to interactions between cosmic rays and nitrogen. Nuclides that are produced by radioactive decay are called radiogenic nuclides , whether they themselves are stable or not.
The helium nuclei that form 10–12% of cosmic rays, are also usually of much higher energy than those from radioactive decay and pose shielding problems in space. However, this type of radiation is significantly absorbed by Earth's atmosphere, which is a radiation shield equivalent to about 10 meters of water. [7]
Hydrogen, as atomic H, is the most abundant chemical element in the universe, making up 75% of normal matter by mass and >90% by number of atoms. [96] In astrophysics, neutral hydrogen in the interstellar medium is called H I and ionized hydrogen is called H II. [97] Radiation from stars ionizes H I to H II, creating spheres of
US Geological Survey researchers say there could be 5.6 trillion metric tonnes of hydrogen in rocks and underground reservoirs Small fraction of hydrogen trapped under Earth can power humanity for ...
A large fraction of the chemical elements that occur naturally on the Earth's surface are essential to the structure and metabolism of living things. Four of these elements (hydrogen, carbon, nitrogen, and oxygen) are essential to every living thing and collectively make up 99% of the mass of protoplasm. [1]
Radiolysis is the dissociation of molecules by ionizing radiation.It is the cleavage of one or several chemical bonds resulting from exposure to high-energy flux.The radiation in this context is associated with ionizing radiation; radiolysis is therefore distinguished from, for example, photolysis of the Cl 2 molecule into two Cl-radicals, where (ultraviolet or visible spectrum) light is used.