A quantitative X-ray microanalysis thin film method using K-, L-, and M-lines

We have developed an improved quantitative X-ray microanalysis method using new relative intensity factors and ionization cross section equations. The method uses K-lines from Z=11 to 60 and all measurable L- and M-lines. Our most important improvement over existing procedures is in the equation for ionization cross section which takes the form Q x ~ b ln ( c U x ) / E x 2 U x d ; where E x =excitation energy, U=overvoltage ( E 0/ E x ), and b, c, and d are functions of atomic number. We obtained experimental k values on particulates of eight stoichiometric compounds using a STEM at 100 and 200 kV. These data and selected values from the literature were used to obtain the following functions for b, c and d: b K( Z⩽30)=8.874-8.158 ln Z+2.9055 (ln Z) 2—0.35778 (ln Z) 3; b K( Z>30)=0.661; b L=0.2704+0.00726 (ln Z) 3; b M= 11.33-2.43 ln Z; c K= c L= c M=1; d K = 1.0667—0.00476 Z; d L = d M = 1. Precision and accuracy data obtained on eight samples using a variety of line combinations gave an overall relative accuracy of±4.4%.