Development and implementation of robust reconstruction methods for small-angle x-ray scattering tensor tomography
Doctoral thesis, 2024

This thesis details the development of an improved theoretical framework, computational methods, and the implementation of scientific software for small-angle x-ray scattering tensor tomography.
It includes experimental and simulation work to evaluate the robustness of the method under constraints on data acquisition and to validate implications of the theory.

Small-angle x-ray scattering tensor tomography is a promising method for the study of millimeter-sized samples with anisotropic nanostructures at scales ranging from a few to several hundred nanometers.
This is accomplished by reconstructing the reciprocal space map of the sample in a volume-resolved manner.
A thorough account is given of the mathematical model and the algorithms used to carry out reconstructions from experimental data.
The performance of these algorithms is investigated through correlation studies on simulated data, demonstrating that they are robust and perform well compared to alternative approaches.
The thesis details the software package Mumott, the structure and development of which is informed by the advances within this project.
In the case of the experimental correlation study, the robustness of the tensor tomographic reconstruction methods for a typical partial data set is evaluated by comparison to the reconstruction obtained with a full data set.
The full data set was acquired by remounting the sample during acquisition.
This analysis shows that while the incompleteness of data has an appreciable adverse effect on the parts of the reconstruction, many important quantities, such as the principal orientation, mean intensity and relative anisotropy, are relatively robust.
Finally, the thesis includes one application study of the structure of the chameleon tongue, where small-angle x-ray scattering tensor tomography is used to complement other imaging methods in a way that leverages the advances in robustness and the study of complex textures detailed in the thesis.

tensor tomography

optimization

hierarchical materials

integral geometry

diffraction

small-angle scattering

nanostructure

visualization

PJ-salen, Fysik Origo
Opponent: Lektor Stephen Hall, Lunds Universitet Institutionen för Byggvetenskaper Avdelningen för Hållfasthetslära

Author

Leonard Nielsen

Chalmers, Physics, E-commons

Small-angle scattering tensor tomography algorithm for robust reconstruction of complex textures

Acta Crystallographica Section A: Foundations and Advances,; Vol. 79(2023)p. 515-526

Journal article

L. C. Nielsen, T. Tänzer, I. Rodriguez-Fernandez, P. Erhart, and M. Liebi, Investigating the missing wedge problem in small-angle x-ray scattering tensor tomography across real and reciprocal space

J. Avaro, L. C. Nielsen, C. Appel, D. Athansiadou, A. Parilli, F. Orellana, L. Davis, U. Hetzel, and M. Liebi, Structure of the Chameleon Tongue: Enabling one of the fastest movements in biology

L. C. Nielsen, M. Carlsen, S. Wang, A. Baroni, T. Tänzer, M. Liebi, and P. Erhart, Mumott – a Python package for tensor tomography

SAXS-tensortomografi är en metod för att i tre dimensioner studera hur nanostrukturen ser ut, på flera längdskalor, inuti prov som är stora nog att se med blotta ögat.
Den har unika fördelar bland annat när det gäller att avgöra bland annat hur fiberliknande strukturer är riktade i tre dimensioner, inuti till exempel skelett och andra biologiska prover. Den har även tillämpningar inom utvecklandet av nya material, till exempel material som efterliknar biologiska vävnader.
Detta arbete handlar om att bättre förstå hur SAXS-tensortomografi fungerar, och att utveckla datorprogram som gör det lättare för forskare att använda tensortomografi och liknande metoder i sitt arbete.
Det ingår även en studie om strukturen inuti en kameleonttunga, som visar på SAXS-tensortomografins unika fördelar.

Small-angle x-ray scattering tensor tomography is a method that allows the study of the nanostructure of samples which are large enough to be seen with the naked eye, in three dimensions.
It has unique advantages in terms of determining how fiber-like structures are oriented in three dimensions, in for example bone or other biological materials. There are also applications in the development of novel materials, especially materials that imitate biological tissues.
This work is about developing a better understanding of small-angle x-ray scattering tensor tomography, as well as the development of software which makes it easier for researchers to use tensor tomography in their own work.
In addition, there is a case study showcasing the application of small-angle x-ray scattering tensor tomography to a sample of chameleon tongue, for the purpose of better understanding its internal structure.

SAXS- and WAXS- tensor tomography: A new tool for the analysis of multi-scale materials

Swedish Research Council (VR) (2018-04144), 2019-01-01 -- 2022-12-31.

Multi-Modal Tensor Tomography (MUMOTT)

European Commission (EC) (EC/H2020/949301), 2021-01-01 -- 2025-12-31.

Areas of Advance

Nanoscience and Nanotechnology

Materials Science

Infrastructure

C3SE (Chalmers Centre for Computational Science and Engineering)

Chalmers e-Commons

Subject Categories

Medical Image Processing

Condensed Matter Physics

ISBN

978-91-8103-055-6

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5513

Publisher

Chalmers

PJ-salen, Fysik Origo

Online

Opponent: Lektor Stephen Hall, Lunds Universitet Institutionen för Byggvetenskaper Avdelningen för Hållfasthetslära

Related datasets

mumott – a Python library for the analysis of multi-modal tensor tomography data [dataset]

DOI: 10.5281/zenodo.7919448

More information

Latest update

5/2/2024 1