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Neutron activation is the process in which neutron radiation induces radioactivity in materials, and occurs when atomic nuclei capture free neutrons, becoming heavier and entering excited states. The excited nucleus decays immediately by emitting gamma rays , or particles such as beta particles , alpha particles , fission products , and ...
An activation product is a material that has been made radioactive by the process of neutron activation.. Fission products and actinides produced by neutron absorption of nuclear fuel itself are normally referred to by those specific names, and activation product reserved for products of neutron capture by other materials, such as structural components of the nuclear reactor or nuclear bomb ...
Free neutrons decay by emission of an electron and an electron antineutrino to become a proton, a process known as beta decay: [2] n 0 → p + + e − + ν e. Although the p + and e − produced by neutron decay are detectable, the decay rate is too low to serve as the basis for a practical detector system.
For the free neutron, the decay energy for this process (based on the rest masses of the neutron, proton and electron) is 0.782 343 MeV. That is the difference between the rest mass of the neutron and the sum of the rest masses of the products. That difference has to be carried away as kinetic energy.
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.
The boundaries of this valley are the neutron drip line on the neutron-rich side, and the proton drip line on the proton-rich side. [2] These limits exist because of particle decay, whereby an exothermic nuclear transition can occur by the emission of one or more nucleons (not to be confused with particle decay in particle physics).
The neutrino [a] was postulated first by Wolfgang Pauli in 1930 to explain how beta decay could conserve energy, momentum, and angular momentum ().In contrast to Niels Bohr, who proposed a statistical version of the conservation laws to explain the observed continuous energy spectra in beta decay, Pauli hypothesized an undetected particle that he called a "neutron", using the same -on ending ...
For a typical neutron star of 1.4 solar masses (M ☉) and 12 km radius, the nuclear pasta layer in the crust can be about 100 m thick and have a mass of about 0.01 M ☉. In terms of mass, this is a significant portion of the crust of a neutron star.