Atomic Cross Section
In physics the cross section is a measure of probability that a specific process will take place in a collision of two particles.
Atomic cross section. For example the rutherford cross section is a measure of probability that an alpha particle will be deflected by a given angle during a collision with an atomic nucleus. Note that light in this context is described as consisting of particles i e photons. 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 units are given in cm 1. When two particles interact their. The larger the neutron cross section the more likely a neutron.
The units are given in barns or cm2. The concept of a nuclear cross section can be quantified physically in terms of characteristic area where a larger area means a larger probability of interaction. The microscopic cross section represents the effective target area of a single target nucleus for an incident particle.
Absorption cross section is a measure for the probability of an absorption process. The nuclear cross section of a nucleus is used to describe the probability that a nuclear reaction will occur. Cross section in nuclear or subatomic particle physics probability that a given atomic nucleus or subatomic particle will exhibit a specific reaction for example absorption scattering or fission in relation to a particular species of incident particle.
More generally the term cross section is used in physics to quantify the probability of a certain particle particle interaction e g scattering electromagnetic absorption etc. Cross section is typically denoted σ and is expressed in terms of the transverse area that the incident particle must hit in order for the given process to occur. The standard unit for measuring the cross section is the barn which is equal to 10 28 m2 or 10 24 cm2.