k0INAA

k0-INAA, or k0 instrumental neutron activation analysis, is a quantitative analytical method used in instrumental neutron activation analysis that relies on pre-determined k0-factors to determine element concentrations without requiring element-specific calibration standards for each irradiation. The approach expresses the concentration of an element in a sample relative to a comparator nuclide, using constants called k0-factors that encapsulate nuclear data and irradiation conditions, including the neutron spectrum.

The core principle involves relating measured gamma-ray intensities from activated nuclei to their concentrations through the k0-factor formalism. Central to the method are parameters that describe the neutron field, notably the thermal-to-epithermal flux ratio (f) and the epithermal-to-thermal ratio (alpha). By measuring a monitor nuclide in the same irradiation and counting the sample and monitor together, one can determine these flux parameters and apply the appropriate k0-values to convert observed activities into concentrations. The k0 approach enables multi-element analysis from a single irradiation without requiring a dedicated calibration standard for every element.

Requirements for successful application include accurate nuclear data (cross sections, decay constants, gamma emission probabilities), a well-characterized neutron spectrum, and careful corrections for phenomena such as self-shielding, self-absorption, and peak interference in gamma spectra. Geometry and counting efficiency must be well understood, and software tools are commonly used to perform the calculations.

Applications of k0-INAA span geology, archaeology, environmental science, and materials analysis, where rapid multi-element determinations are valuable. While it reduces the need for many standards and enhances comparability, its accuracy depends on the quality of nuclear data and the stability of irradiation conditions.