What is neutron activation?

Neutron activation refers to the process by which stable isotopes become radioactive after capturing neutrons. When a stable nucleus absorbs a neutron, it can become unstable and subsequently undergo radioactive decay. This process is significant in various applications, including the activation analysis method used to identify and quantify materials.

In many nuclear reactions, particularly in reactors, neutrons are used to interact with stable isotopes in fuel and other materials. When these isotopes capture neutrons, they may transform into a different isotope, which can be radioactive. This transformation can lead to the production of radiopharmaceuticals, isotopes for industrial applications, or can contribute to the fission process itself in nuclear reactors.

The other options provided do not accurately define neutron activation. The reduction of neutron population refers to the control of neutron balance in a reactor but does not involve the activation process. The notion of determining the detention of neutrons in a magnetic field pertains to magnetic confinement, which is not applicable to neutron activation. Finally, the splitting of heavy atomic nuclei describes nuclear fission, which is a separate phenomenon from neutron activation.