(n-p) reaction

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The (n-p) reaction is an example of a nuclear reaction. It is the reaction which occurs when a neutron enters a nucleus and a proton leaves the nucleus simultaneously.[1]

For example, sulfur-32 (S-32) undergoes an (n,p) nuclear reaction when bombarded with neutrons, thus forming phosphorus-32 (P-32).

The nuclide nitrogen-14 (N-14) can also undergo an (n,p) nuclear reaction to produce carbon-14 (C-14); this nuclear reaction 14N (n,p) 14C continually happens in the earth's atmosphere, forming equilibrium amounts of the radionuclide carbon-14.

Most (n,p) reactions have threshold neutron energies below which the reaction cannot take place as a result of the charged particle in the exit channel requiring energy (usually more than a MeV) to overcome the Coulomb barrier experienced by the emitted proton; the (n,p) nuclear reaction 14N (n,p) 14C is an exception to this rule, and is exothermic - it can take place at all incident neutron energies.[citation needed] The 14N (n,p) 14C nuclear reaction is responsible for most of the radiation dose delivered to the human body by thermal neutrons—these thermal neutrons are absorbed by the nitrogen (N-14) in proteins, causing a proton to be emitted; the emitted proton deposits its kinetic energy over a very short distance in the body tissue, thereby depositing radiation dose.


  1. ^ Jha, D.K. (2004). Elements Of Nuclear Reactors. Discovery Publishing House. p. 65. ISBN 978-81-7141-883-1.