Question

What are incident neutrons??

Answer 1

neutrons are uncharged particles therefore they do not participate in electro magnetic interactions and do not produce ionization of atoms. the interaction of neutron magnetic moment with matter with matter is very weak and unlikely.

incident neutrons are the neutrons incident on the matter and their interaction with matter depend upon neutron cross section

when a neutron strikes a piece of matter it does not interact with the atomic electrons instead nucleus interact with the nuclei. these neutron interactions can result in the transfer of energy from the target to nucleus or in a neutron induced disintegration. the capture of neutron by a nucleus often results in the formation of a radioactive isotope.

the probability of a particular event occurring between a neutron and a nucleus is expressed through the concept of the cross section. if a large number of neutrons of the same energy are directed into a thin layer of material, some may pass through with no interactions, others may have interactions that change their directions and energies and others may fail to emerge from the sample. there is a probability of each event.`

the cross section for being absorbed is the probability of neutrons being absorbed divided by the areal atom density

a neutron can have many types of interactions with a nucleus. an interaction may be one of two major types: scattering and absorption. when a neutron is scattered by a nucleus, its speed and direction change but the nucleus is left with the same number of protons and neutrons it had before the interaction the nucleus will have some recoil velocity and it may be left in an excited state that will lead to the eventual release of radiation

when a neutron is absorbed by a nucleus, a wide range of radiations can be emitted or fission can be induced