Neutron Activation Analysis
Bombarding a sample with neutrons makes trace elements radioactive; the characteristic radiation they emit reveals composition with high sensitivity.
Reading composition from radiation
Neutron activation analysis (NAA) determines what a material is made of. When neutrons irradiate a sample, some nuclei capture them and become radioactive isotopes. Each such isotope emits radiation at characteristic energies as it decays. Measuring those energies and intensities identifies which elements are present and in what quantities.
Why it is powerful
- High sensitivity: detects trace elements at very low levels.
- Non-destructive for many samples.
- Element-specific: characteristic energies identify each element.
- Fusion neutrons open activation channels lower energies cannot.
NAA is used in materials science, quality assurance, forensics, and safeguards. The 14 MeV fusion neutron is particularly useful because its high energy activates reactions that lower-energy neutrons cannot, extending the range of elements and isotopes that can be analyzed.
Domestic capability
High-energy channels
What distinguishes activation analysis with 14 MeV neutrons from conventional thermal activation is the set of reactions the high energy makes accessible. Fast neutrons can induce reactions that slow neutrons cannot, activating isotopes and elements that would otherwise be invisible to the technique. This extends the range of compositions that can be measured and can provide independent confirmation of results obtained by other methods. A domestic fusion-neutron source therefore broadens analytical capability, letting users characterize materials that thermal activation alone would leave incompletely described.
A domestic 14 MeV source, as studied for the breeder, supports high-energy activation analysis for users who need it. As with the machine's other neutron services, this is a design-stage capability realized through FOAK operation rather than a present offering.