• fast neutron
  • In the most important reaction for natural production, a fast neutron (which must have energy greater than 4.0 MeV) interacts with atmospheric nitrogen: Worldwide, the production of tritium from natural sources is 148,000 terabecquerels per year. (wikipedia.org)
  • radon
  • In this case, radium decays into radon gas. (blogspot.com)
  • Upon disintegration, in the case of radon and its progeny, the radiation released is primarily in the form of an alpha particle - or two protons and two neutrons - that has the potential t o cause lung cancer. (blogspot.com)
  • It is the chemistry of radioactive elements such as the actinides, radium and radon together with the chemistry associated with equipment (such as nuclear reactors) which are designed to perform nuclear processes. (wikipedia.org)
  • Another 50 or so shorter-lived radionuclides, such as radium and radon, found on Earth, are the products of decay chains that began with the primordial nuclides, or are the product of ongoing cosmogenic processes, such as the production of carbon-14 from nitrogen-14 in the atmosphere by cosmic rays. (wikipedia.org)
  • occur
  • Formation of elements with from 6 to 26 protons occurred and continues to occur in main sequence stars via stellar nucleosynthesis. (wikipedia.org)
  • uranium
  • Radioactivity was discovered in 1896 by Henri Becquerel in uranium, and subsequently observed by Marie and Pierre Curie in thorium and in the new elements polonium and radium. (wikipedia.org)
  • As a radioactive compound, uranium disintegrates or decays releasing progeny (or daughter) products such as radium, along with energy in the form of radiation. (blogspot.com)
  • nuclide
  • The decaying nucleus is called the parent radionuclide (or parent radioisotope), and the process produces at least one daughter nuclide. (wikipedia.org)
  • cosmic rays
  • Naturally occurring tritium is extremely rare on Earth, where trace amounts are formed by the interaction of the atmosphere with cosmic rays. (wikipedia.org)
  • Tritium occurs naturally due to cosmic rays interacting with atmospheric gases. (wikipedia.org)
  • Although tritium is formed naturally through the interaction of cosmic rays with the atmosphere, it does not accumulate because of its short half-life of 12.3 years. (alienscientist.com)
  • photons
  • Typically photons begin to produce neutrons on interaction with normal matter at energies of about 7 to 40 MeV, which means that radiotherapy facilities using megavoltage X-rays also produce neutrons, and some require neutron shielding. (wikipedia.org)
  • decay
  • In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta ray (fast energetic electron or positron) and a neutrino are emitted from an atomic nucleus. (wikipedia.org)
  • Neither the beta particle nor its associated neutrino exist within the nucleus prior to beta decay, but are created in the decay process. (wikipedia.org)
  • The unusually low energy released in the tritium beta decay makes the decay (along with that of rhenium-187) appropriate for absolute neutrino mass measurements in the laboratory (the most recent experiment being KATRIN). (wikipedia.org)
  • Because its decay products cause phosphors to glow, tritium is used in self-illuminating devices found in watches, exit signs, and gun sights. (alienscientist.com)
  • Decay products from a nucleus with spin may be distributed non-isotropically with respect to that spin direction, either because of an external influence such as an electromagnetic field, or because the nucleus was produced in a dynamic process that constrained the direction of its spin. (wikipedia.org)
  • Another type of radioactive decay results in products that vary, appearing as two or more "fragments" of the original nucleus with a range of possible masses. (wikipedia.org)
  • fragments
  • Because of their tremendous penetrating ability, neutrons can be very damaging to the human body, a fact well known by the U.S. military, which is developing a bomb designed to kill people (but preserve property) by emitting large quantities of lethal neutron fragments. (ratical.org)
  • The smallest of these fragments in ternary processes ranges in size from a proton to an argon nucleus. (wikipedia.org)
  • reaction
  • This is possible with neutrons of any energy, and is an exothermic reaction yielding 4.8 MeV. (wikipedia.org)
  • High-energy neutrons can also produce tritium from lithium-7 in an endothermic (a net heat consuming reaction) reaction, consuming 2.466 MeV. (wikipedia.org)
  • This reaction has a quite small absorption cross section, making heavy water a good neutron moderator, and relatively little tritium is produced. (wikipedia.org)
  • Nuclear power relies on fissionable material that can sustain a chain reaction with neutrons. (wikipedia.org)
  • In order to efficiently convert the heat produced by the Nuclear Reaction into electricity, the water that moderates the neutron and cools the fuel elements is contained at pressures 150 times greater than atmospheric pressure. (nuclearinfo.net)
  • absorption
  • Deuterium's absorption cross section for thermal neutrons is about 0.52 millibarns, whereas that of oxygen-16 (16 8O ) is about 0.19 millibarns and that of oxygen-17 (17 8O ) is about 240 millibarns. (wikipedia.org)