Relative intensity factors for K, L and M shell x-ray lines

Accurate values for x‐ray relative intensity factors, which are the fraction of intensity measured, are important for quantitative calculation procedures used in scanning transmission electron microscope thin film x‐ray microanalysis. We have developed equations for calculating these parameters for the K, L and M shells and have applied them to a thin film quantitative analysis procedure. The K shell values were obtained from experimental and theoretical data in the literature and show a constant region between atomic numbers 20 and 30. To obtain L shell values measurements were made with an electron probe and an energy dispersive system on a 200 kV scanning transmission electron microscope. These data were combined with values calculated from Coster‐Kronig and fluorescence yield data in the literature. The result was two curves with a step at atom number 51 and a significantly different magnitude than values used in other thin film methods. The following equations for use in a computer program were developed from these curves; aLα1.2(Z=27−50)=1.617−0.0398Z+3.766 × 10−4Z2; aLα1,2(Z=51−92)=0.609−1.619 × 10−3Z−0.03248 sin [0.161(Z−51)].