Three-dimensional fast elemental mapping by soft X-ray dual-energy focal stacks imaging.

Limei Ma,Zhi Guo,Benjamin Watts,Zijian Xu,Xiangzhi Zhang,Jinyou Lin,Renzhong Tai

doi:10.1107/s1600577521002903

Abstract

The three-dimensional (3D) dual-energy focal stacks (FS) imaging method has been developed to quickly obtain the spatial distribution of an element of interest in a sample; it is a combination of the 3D FS imaging method and two-dimensional (2D) dual-energy contrast imaging based on scanning transmission soft X-ray microscopy (STXM). A simulation was firstly performed to verify the feasibility of the 3D elemental reconstruction method. Then, a sample of composite nanofibers, polystyrene doped with ferric acetylacetonate [Fe(acac)3], was further investigated to quickly reveal the spatial distribution of Fe(acac)3 in the sample. Furthermore, the data acquisition time was less than that for STXM nanotomography under similar resolution conditions and did not require any complicated sample preparation. The novel approach of 3D dual-energy FS imaging, which allows fast 3D elemental mapping, is expected to provide invaluable information for biomedicine and materials science.

Highlights

Porous electrospun nanofibers, as superior one-dimensional nanostructures, have been applied in many fields such as electrochemical anodization, catalysis, absorption, etc. (Gonzalez del Campo et al, 2018; Zhang, Han et al, 2010; Jo et al, 2018)
In transmission electron microscopy, sample preparation and mechanical slicing procedures are essential for thick samples, and scanning electron microscopy only enables surface or cross-section microstructures to be observed (McIntosh et al, 2005; Wei et al, 2017)
To quickly distinguish the spatial distribution of Fe(acac)3 in the porous composite nanofibers, a 3D dual-energy focal stacks (FS) experiment was carried out based on soft X-ray microscope (STXM) for Fe(acac)3 spatial localization

Summary

Introduction

As superior one-dimensional nanostructures, have been applied in many fields such as electrochemical anodization, catalysis, absorption, etc. (Gonzalez del Campo et al, 2018; Zhang, Han et al, 2010; Jo et al, 2018). Of polymer 3D structures (Denk & Horstmann, 2004) All of these methods are able to achieve elemental mapping when they are further combined with spectral 2. STXM, is performed to achieve 2D elemental mapping (Ade based on density, element and different contrast of samples to et al, 1992; Jiang et al, 2010; Smit et al, 2008) The dual-energy ratiodistributions of intracellular nanomaterials in three dimen- contrast algorithm or K-edge subtraction algorithm is sions in macrophages by combining the dual-energy contrast performed to elucidate detailed spatial distributions of the imaging method and sloped tomography 66 min (Ma et al, 2019)

Simulation

Experiment

Conclusion