Evaluation Models

For the identification of nuclides based on their characteristic lines, all spectra are considered; their quantification is usually based on the net counting rates of the (unperturbed) characteristic lines in the summed spectrum. The reason for this is mainly the significantly better statistics in the summed spectrum, i.e., the higher net counting rates.
Various evaluation models have been developed for quantification. So far, a model based on the relation [DIN EN ISO 19017] has been standardized.

\[ a = T \cdot Z \]

An established model has been found.

The specific activity a of a radionuclide in the container is linked to the measured net counting rate Z of a characteristic line through a transfer function T, which describes the proportionality between the sought quantity a and the measured quantity Z. The transfer function is also referred to as the correlation function.

Often, the sought quantity is the activity A of a radionuclide. This can be calculated from the specific activity a by multiplying with the mass M.

\[A = M \cdot a \]

The mass M is the net mass, i.e., the mass of the waste product or the volume containing activity.

The determination of the transfer function can be carried out experimentally, through mathematical relationships, or through simulation calculations.
The procedure for determining the transfer function is directly connected with the respective used measurement mode and the used evaluation model.