Mesoscale X-Ray Physics for the Environment

Breiby Group

Scientific interests:

Environmental science & porous materials

A considerable fraction of our current project portfolio is in the field of environmental science and geophysics. Here are some selected recent highlights:

- Tensor SAXS imaging of hydroxyapatite orientation in “dinosaur” bones (Mürer, Sci. Rep. 2018), and bone orientation near the bone-cartilage growth front in piglets (Mürer, Sci. Rep. 2020).

- In situ imaging of CO₂-induced reactions in cement under conditions realistic for CO₂ storage in abandoned oil/gas reservoirs (Chavez, Env. Sci. Tech. 2020). This kind of information is of crucial importance for developing carbon capture, sequestration and storage (CCS) techniques. The work was done in collaboration with Prof. Francois Renard at UiO, and is financed by the Norwegian Research Council.

Current lines of effort are mainly: strain localization in shale rocks; multiphase flow in porous media; neutron imaging of liquid permeation in biological and geological materials; freezing and thawing of snow, ice and soil.

Coherent X-ray diffractive imaging (CXDI/CDI & ptychography)

The group is strongly involved in the development of coherent X-ray diffraction imaging and ptychography, which is a lensless imaging technique based on iterative phase reconstruction from diffraction images. Using ptychography, we have for example non-destructively studied the wetting of pore channels inside natural organic fibers and thin films. Ptychography can be performed under realistic conditions, including high temperatures and high gas pressures. Efforts are thus made to perform in situ imaging experiments with a resolution approaching 10 nm, in collaboration with leading synchrotron facilities, notably the cSAXS beamline at SLS and the ID10 beamline at ESRF. We have several research projects running with funding from the Norwegian Research Council relating to this line of research (FRINATEK and NANO2021).

In addition to the X-ray based studies, we also have considerable efforts within coherent optical microscopy, in particular Fourier ptychography, in collaboration with Prof. Akram and his group at USN.

Organic electronics – thin film structures

Our group has for many years been working with fundamental structure-properties studies of functional organic materials, mainly polymers, but also small molecules and liquid crystals. The main tools used for these efforts were X-ray reflectivity and grazing incidence X-ray diffraction (GIXD/GISAXS/GIWAXS) of thin films. GIXD is an important technique for revealing structures in thin films, and we have developed considerable expertise in collecting, interpreting and modeling this kind of data, increasingly often in collaboration with experts on density functional theory. These investigations are usually combined with other experimental or theoretical efforts to yield insight into how materials behave the way they do. Typical examples are anisotropic charge-carrier mobility in field-effect transistors or morphology for organic solar cells. These studies on organic electronics have attracted wide-spread attention, and we are collaborating with many of the leading groups in the world in this field, cf. list of publications.

Home laboratory

We are running a national infrastructure site for X-ray scattering, diffraction and imaging.

The instruments we run, open to external users upon reasonable request, include:

- A micro-Computed Tomography instrument (Nikon HT220)

- A custom-made phase-contrast nano-Computed Tomogrpahy (under commissioning)

- A custom setup for wide and small-angle X-ray scattering/diffraction

Microsystems

The group is interested in microsystems (MEMS), particularly for photonics and microscopy applications, and is collaborating with the nationally leading institution (Department of Microsystems, University of South-Eastern Norway) in this field.

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