Neutron activation analysis



Neutron activation analysis is a very sensitive method of quantitative multi-elemental analysis. It has the potential to determine concentrations in a sample from ppb to tens of percent, depending on the particular element and bulk matrix composition.



Samples are irradiated in the OPAL research reactor. After irradiation the specific activity of each radionuclide in the sample may be determined by measuring the energy and intensity of characteristic gamma rays that are emitted.


Radionuclides that have a short half-life (minutes to hours) are best measured after a short irradiation and those with a long half-life (days to years) are irradiated for a longer time.


To offer the greatest flexibility to clients and collaborators, both the relative method of standardisation and the k0-method of standardisation have been implemented.


The neutron spectrum at the NAA irradiation positions in the OPAL reactor is very highly thermalised, with a thermal to epithermal ratio (f) of greater than 1,500. Many of the interfering reactions produced in other research reactors are avoided in the OPAL facility.

Learn more about typical applications of neutron activation analysis, the elements that can be quantified, and client information.


Strengths of neutron activation analysis   


  • Minimal sample preparation for solid forms and powders.
  • Large dynamic range of concentrations, from ppm or even ppb to tens of percent.
  • Large dynamic range of sample weights, from a few mg up to several g.
  • Good accuracy with typical uncertainties around 4 to 5% and good precision.
  • The multi-element capability provided by the k0-method means that up to 65 elements can be quantified with just two irradiations.
  • Fully traceable to primary SI-standards. The relative method is recognised as a primary ratio method.
  • Quality in our laboratory is assured through the use of certified reference materials and participation in international intercomparisons at the highest metrological level, such as CCQM key comparisons. 



To discuss your analytical needs, please complete our online contact form.