Procedure for the determination of the amount of a given element in a sample by means of X radiation

The quantity of a certain element in a sample is determined from the intensity of the X-ray fluorescence radiation from that element by means of a subtraction procedure. First the sample is irradiated with X-rays of a wavelength (lambda) not longer than the absorption edge of the element. Secondly it is then irradiated with shorter wavelength X-rays (lambda-d). The fluorescence produced in both cases is measured and the difference in intensity between the measurements can be used to determine the quantity of the desired element. (Th.P.)