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Neutron radiation is a form of ionizing radiation that presents as free neutrons.Typical phenomena are nuclear fission or nuclear fusion causing the release of free neutrons, which then react with nuclei of other atoms to form new nuclides—which, in turn, may trigger further neutron radiation.
Free neutrons do not directly ionize atoms, but they do indirectly cause ionizing radiation, so they can be a biological hazard, depending on dose. A small natural "neutron background" flux of free neutrons exists on Earth, caused by cosmic ray showers , and by the natural radioactivity of spontaneously fissionable elements in the Earth's crust .
Alpha (α) particles consist of two protons and two neutrons bound together into a particle: a helium-4 nucleus. Alpha particle emissions are generally produced in the process of alpha decay . Alpha particles are a strongly ionizing form of radiation, but when emitted by radioactive decay they have low penetration power and can be absorbed by a ...
In addition, high-energy (high-speed) neutrons have the ability to directly ionize atoms. One mechanism by which high energy neutrons ionize atoms is to strike the nucleus of an atom and knock the atom out of a molecule, leaving one or more electrons behind as the chemical bond is broken. This leads to production of chemical free radicals. In ...
The neutron activation of the soon-to-be vaporized metal is responsible for a significant portion of the nuclear fallout in nuclear bursts high in the atmosphere. In other types of activation, neutrons may irradiate soil that is dispersed in a mushroom cloud at or near the Earth's surface, resulting in fallout from activation of soil chemical ...
The trend in the ionization energy of atoms is often used to demonstrate the periodic behavior of atoms with respect to the atomic number, as summarized by ordering atoms in Mendeleev's table. This is a valuable tool for establishing and understanding the ordering of electrons in atomic orbitals without going into the details of wave functions ...
Nucleons are thought to be composed of two kind of particles, the neutron and the proton that differ through their intrinsic property, associated with their iso-spin quantum number. This concept enables the explanation of the bound state of Deuterium, in which the proton and neutron can couple their spin and iso-spin in two different manners ...
A model of an atomic nucleus showing it as a compact bundle of protons (red) and neutrons (blue), the two types of nucleons.In this diagram, protons and neutrons look like little balls stuck together, but an actual nucleus (as understood by modern nuclear physics) cannot be explained like this, but only by using quantum mechanics.