Optimal Kα XRF detection geometry of arsenic in skin using an extended fundamental parameter method

The fundamental parameter (FP) method was extended to account for the geometrical details of experimental x‐ray fluorescence (XRF) detection. In the traditional FP method the primary fluorescence photons have parallel pathways towards the detector. In the new approach the primary fluorescence photons can travel in any direction which allows them to reach the detector if not absorbed or scattered. The derived XRF signal equation explicitly depends on the length of the collimator in front of the detector, the detector size, position and orientation. An algorithm which numerically calculates the XRF signal for any set of parameters was developed and implemented for the K_α XRF signal of arsenic in skin. Optimal positions and orientations of the detector and collimator ensemble which maximize the XRF signal were found. Results and limitations of the method were also discussed. Copyright © 2009 John Wiley & Sons, Ltd.