Polarized Radiation Produced by Scatter for Energy Dispersive X-ray Fluorescence Trace Analysis

Abstract

Polarized x-radiation produced by scatter at 90° from boron carbide is shown to be a superior excitation source for the measurement of trace elements by energy dispersive x-ray fluorescence. In a close-coupled system which uses a high power x-ray tube as the primary source, the losses due to the geometric requirements and scattering efficiency of the polarizer can be more than compensated. With the system described here which uses a Mo anode x-ray tube, detection limits for the element between K and Sr in NBS orchard leaves are approximately 2 to 4.5 times lower using polarized excitation in comparison to direct excitation, and about <1 to 3 times lower in comparison to secondary excitation.