VARIABLE X-RAY-EXCITATION FOR TOTAL-REFLECTION X-RAY-FLUORESCENCE SPECTROMETRY USING AN MO W ALLOY ANODE AND A TUNABLE DOUBLE MULTILAYER MONOCHROMATOR/

A new total reflection X-ray fluorescence spectrometer has been develo ped which uses a variable double multilayer arrangement as a tunable m onochromator together with an X-ray fine structure tube which is chara cterized by an anode made of a homogeneous alloy of molybdenum and tun gsten. Three discretely adjustable excitation energies, namely 9.7 keV , 17.5 keV and 35 keV, are supplied by this combination. The detection limits were determined to be 0.4 pg nickel using W L beta excitation, 0.6 pg lead using Mo K alpha excitation and 8 pg cadmium using 35 keV bandpass excitation. (C) 1997 Elsevier Science B.V.