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Neutron capture is a nuclear reaction in which an atomic nucleus and one or more neutrons collide and merge to form a heavier nucleus. [1] Since neutrons have no electric charge, they can enter a nucleus more easily than positively charged protons , which are repelled electrostatically .
In nuclear astrophysics, the rapid neutron-capture process, also known as the r-process, is a set of nuclear reactions that is responsible for the creation of approximately half of the atomic nuclei heavier than iron, the "heavy elements", with the other half produced by the p-process and s-process.
The slow neutron-capture process, or s-process, is a series of reactions in nuclear astrophysics that occur in stars, particularly asymptotic giant branch stars.The s-process is responsible for the creation (nucleosynthesis) of approximately half the atomic nuclei heavier than iron.
Neutron capture nucleosynthesis describes two nucleosynthesis pathways: the r-process and the s-process, for rapid and slow neutron captures, respectively. R-process describes neutron capture in a region of high neutron flux , such as during supernova nucleosynthesis after core-collapse, and yields neutron-rich nuclides .
Neutron activation is the only common way that a stable material can be induced into becoming intrinsically radioactive. All naturally occurring materials, including air, water, and soil, can be induced (activated) by neutron capture into some amount of radioactivity in varying degrees, as a result of the production of neutron-rich radioisotopes.
While the best-known neutron reactions are neutron scattering, neutron capture, and nuclear fission, for some light nuclei (especially odd-odd nuclei) the most probable reaction with a thermal neutron is a transfer reaction: Some reactions are only possible with fast neutrons:
Nuclides with mass number greater than 64 are predominantly produced by neutron capture processes—the s-process and r-process–in supernova explosions and neutron star mergers. The Solar System is thought to have condensed approximately 4.6 billion years before the present, from a cloud of hydrogen and helium containing heavier elements in ...
Neutron capture therapy is a binary system that consists of two separate components to achieve its therapeutic effect. Each component in itself is non-tumoricidal, but when combined they can be highly lethal to cancer cells. 1) Boron compound (b) is selectively absorbed by cancer cell(s). 2) Neutron beam (n) is aimed at cancer site.