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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 rates of weak decay of two radioactive species with half lives of about 40 s and 200 s are found to have a significant oscillatory modulation, with a period of about 7 s. [52] The observed phenomenon is known as the GSI anomaly , as the storage ring is a facility at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt , Germany .
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 ...
The radiation appeared to have two different characters, the first he called "radiation" and the more penetrating one he called "radiation". After five years of additional experimental work, Rutherford and Hans Geiger determined that "the alpha particle, after it has lost its positive charge, is a Helium atom".
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.