What does 'neutron activation' refer to?

Neutron activation refers to a process in which stable isotopes absorb neutrons and subsequently become radioactive isotopes. This transformation occurs because the additional energy from the absorbed neutron alters the nucleus of the atom, often resulting in the creation of a new, unstable isotope that may undergo radioactive decay.

This process is widely utilized in various fields, such as nuclear medicine, where neutron activation analysis can be used to determine concentrations of elements in samples. By doing so, scientists can gain important insights into the composition of materials, ranging from environmental samples to biomedical materials.

The other options do not accurately describe neutron activation; they pertain to unrelated concepts within radiation and its applications. The focus on the transformation of isotopes through neutron absorption is what distinctly characterizes neutron activation, making it essential in both scientific research and practical applications.