TRACE HEAVY ELEMENT ANALYSIS USING X-RAY-FLUORESCENCE WITH QUASI-MONOCHROMATIC HIGH-ENERGY PHOTONS - IODINE IN AN ENVIRONMENTAL SAMPLE

X-ray fluorescence with high-energy photon excitation is a promising m ethod for heavy element analysis. For trace determination, however, it is necessary to optimize the excitation spectrum. In this study, quas i monochromatization by a primary-beam filter and by a secondary targe t is quantitatively studied in order to detect an important bioelement , iodine, in an environmental sample. The primary-beam-filter techniqu e gives the lowest detection limit, which is 1/5th the limit given by white excitation.