The multiconfiguration Dirac-Fock method was used to compute the relative i
ntensities of K beta to K alpha x-rays (K beta /K alpha) for several elemen
ts in the range 20 less than or equal to Z less than or equal to 80. We inv
estigate the effect of the Breit interaction on K beta /K alpha ratios and
find it negligible. The results are compared with experimental data and oth
er theoretical calculations.