[en] Parameters for generating fluorescence radiation are given, for example, in ISO 4037-1. These parameters are the high voltage of the X ray tube, the mass per area of the aluminium primary filter behind the X ray tube, the material and mass per area of the fluorescence target and the secondary filter. A computer program was developed to calculate the generated fluorescence spectra. The results of these calculations have shown that the parameters for the generation of fluorescence radiation given in ISO 4037-1 can be optimised. The program was checked by comparison of the calculations with experiments for two different radiation qualities. Optimised parameters were determined for different fluorescence radiation qualities (as contained in ISO 4037-1 and others). (author)