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A fixed source calculation involves imposing a known neutron source on a medium and determining the resulting neutron distribution throughout the problem. This type of problem is particularly useful for shielding calculations, where a designer would like to minimize the neutron dose outside of a shield while using the least amount of shielding ...
Quantity (common name/s) (Common) symbol/s Defining equation SI units Dimension Number of atoms N = Number of atoms remaining at time t. N 0 = Initial number of atoms at time t = 0
The multiplication factor, k, is defined as (see nuclear chain reaction): k = number of neutrons in one generation / number of neutrons in preceding generation . If k is greater than 1, the chain reaction is supercritical, and the neutron population will grow exponentially.
For a neutron, the result of this calculation is that the magnetic moment of the neutron is given by μ n = 4/3 μ d − 1/3 μ u, where μ d and μ u are the magnetic moments for the down and up quarks, respectively. This result combines the intrinsic magnetic moments of the quarks with their orbital magnetic moments, and assumes the three ...
[1] [page needed] In conjunction with the neutron flux, it enables the calculation of the reaction rate, for example to derive the thermal power of a nuclear power plant. The standard unit for measuring the cross section is the barn, which is equal to 10 −28 m 2 or 10 −24 cm 2. The larger the neutron cross section, the more likely a neutron ...
Neutron flux in asymptotic giant branch stars and in supernovae is responsible for most of the natural nucleosynthesis producing elements heavier than iron.In stars there is a relatively low neutron flux on the order of 10 5 to 10 11 cm −2 s −1, resulting in nucleosynthesis by the s-process (slow neutron-capture process).
If k is greater than 1, the chain reaction is supercritical, and the neutron population will grow exponentially. If k is less than 1, the chain reaction is subcritical, and the neutron population will exponentially decay. If k = 1, the chain reaction is critical and the neutron population will remain constant.
A thermal neutron is a free neutron with a kinetic energy of about 0.025 eV (about 4.0×10 −21 J or 2.4 MJ/kg, hence a speed of 2.19 km/s), which is the energy corresponding to the most probable speed at a temperature of 290 K (17 °C or 62 °F), the mode of the Maxwell–Boltzmann distribution for this temperature, E peak = k T.