Energy- and position-sensitive pixel detector Timepix for X-ray fluorescence imaging

The position- and energy-sensitive Timepix semiconductor detector presents a significant potential for X-ray fluorescence (XRF) imaging. However, limited energy resolution of this device restrains direct element identification via their radiation pattern. Based on the theoretical Monte Carlo simulations and measured data a per pixel spectra decomposition method has been proposed. This method consists of two phases-the first phase determines the response of each pixel to the characteristic radiation of individual elements and the second phase determines the decomposition of an unknown complex spectra to a set of individual elemental spectra. With a precise per pixel calibration this technique allows us to distinguish the spatial distribution of elements. We are able to recognize elements which are heavier than potassium (e.g. calcium, scandium and titanium). Including elements whose characteristic radiation lines are located in a narrow energetic range (nickel, copper and zinc). The spatial resolution of images is directly determined by the diameter of the pinhole (we present results with a 200 mu m pinhole). (C) 2009 Elsevier B.V. All rights reserved.