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In nuclear physics, the concept of a neutron cross section is used to express the likelihood of interaction between an incident neutron and a target nucleus. The neutron cross section σ can be defined as the area in cm 2 for which the number of neutron-nuclei reactions taking place is equal to the product of the number of incident neutrons that would pass through the area and the number of ...
The cross section obtained in this way is called the total cross section and is usually denoted by a σ or σ T. Typical nuclear radii are of the order 10 −15 m. Assuming spherical shape, we therefore expect the cross sections for nuclear reactions to be of the order of π r 2 {\displaystyle \pi r^{2}} or 10 −28 m 2 (i.e., 1 barn).
The absorption neutron cross section of an isotope of a chemical element is the effective cross-sectional area that an atom of that isotope presents to absorption and is a measure of the probability of neutron capture. It is usually measured in barns. Absorption cross section is often highly dependent on neutron energy. In general, the ...
The first printed edition of the Karlsruhe Nuclide Chart of 1958 in the form of a wall chart was created by Walter Seelmann-Eggebert and his assistant Gerda Pfennig. Walter Seelmann-Eggebert was director of the Radiochemistry Institute in the 1956 founded "Kernreaktor Bau- und Betriebsgesellschaft mbH" in Karlsruhe, Germany (a predecessor institution of the later "(Kern-)Forschungszentrum ...
In physics, the cross section is a measure of the probability that a specific process will take place in a collision of two particles. For example, the Rutherford cross-section is a measure of probability that an alpha particle will be deflected by a given angle during an interaction with an atomic nucleus.
The predecessor group to the NNDC was founded in 1951 when a group known as the Brookhaven Neutron Cross Section Compilation Group was formed at the Brookhaven National Laboratory. In 1955 this group published the reference book "BNL-325," which had to do with the cross-sections of neutrons. After being renamed the Sigma Center, the group was ...
A barn (symbol: b) is a metric unit of area equal to 10 −28 m 2 (100 fm 2).Originally used in nuclear physics for expressing the cross sectional area of nuclei and nuclear reactions, today it is also used in all fields of high-energy physics to express the cross sections of any scattering process, and is best understood as a measure of the probability of interaction between small particles.
Deterministic methods usually involve multi-group approaches while Monte Carlo can work with multi-group and continuous energy cross-section libraries. Multi-group calculations are usually iterative, because the group constants are calculated using flux-energy profiles, which are determined as the result of the neutron transport calculation.