As shown in the model, n is the number of incident X-ray Energies. For example, tow incident energies are commonly Observed corresponding to Ka and KB peaks. For these cases, N=2. This model can also be used in those cases With more Incident energies such as La and LB X-rays that are also recorded Together with K shell X-rays. The linear parameters (denoted as A1,A2,and A3…) are the normalized response function constants Such that