A Low Energy X-Ray Fluorescence spectrometer for elemental mapping X-Ray microscopy

Abstract

In this work we present a recently developed Low Energy X-ray Fluorescence spectrometer (LEXRF) system combined with a soft and multi-keV X-ray Microscope. The LEXRF setup is a modular system based on the use of multiple large area Silicon Drift Detectors (SDD), with the option of up-scaling it to 8 detectors. The detectors are read-out by a custom designed electronics based on a high performance pulsed-reset charge sensitive preamplifier and a fast multichannel acquisition system optimized for elemental mapping. The LEXRF setup has been designed and adapted to the European TwinMic microscope station located at Elettra synchrotron light facility in Trieste, Italy. TwinMic is a transmission X-ray microscope working in the energy range 250–2300 eV. It is a multipurpose end station that combines the advantages of projection imaging, full-field imaging and scanning transmission X-ray microscopy (STXM), with easy switch between the modes. Zone plate diffractive optics are used to focus the X-ray beam down to sub-100 nm spot size depending on the photon energy, imaging and contrast mode. Coupling XRF with STXM allows combining chemical specificity with the morphological information acquired in transmission. With the developed system XRF maps, absorption images and phase contrast images can be collected simultaneously with high spatial resolution. Some examples of XRF maps, absorption images and phase contrast images collected on environmental and biological samples (human cells) will be shown and discussed, highlighting the capability of the newly implemented X-ray emission mode.