Non-monotonic behaviour of the K beta '(2)/K beta '(1) x-ray intensity ratio in the atomic number region 40 <= Z <= 50

The K beta (1)' /K alpha (1), K beta (2)' /K alpha (1) and K beta (2)' /K b eta (1)', intensity ratios were determined for the elements zirconium throu gh tin using proton-induced x-ray spectra recorded with a Si(Li) detector. Careful attention was paid to Compton-scattering artefacts and to radiative Auger features in the nonlinear least-squares fitting of the spectra. The K beta (1)' /K alpha (1) ratio agrees with Dirac-Fock theory. The K beta (2 )' /K beta (1)' results support a recent observation of solid-state enhance ment of the KN4,5 line in Mo and are suggestive of somewhat lesser enhancem ent for other elements where the 4d shell is about half full. The ratios fo r Ag and Cd are significantly larger than the theoretical predictions altho ugh the 4d shell is full in these cases.