X-ray Microtomography

National School on Neutron and X-ray Scattering August 14-28 2005

Group D

Jiong Hua

Vaibhav Kohli

Soonjoo Seo

Lu Zou

Paul J. Sideris

X-ray Computed Microtomography

Imaging tool using high flux at photon energies up to 100 keV. APS bending magnet source: 20 keV

High resolution, 3D images of various porous media

Characterization of fluid phases

Transport of multiphase flow

Why Microtomography?

Non-Invasive examination of the internal structure of objects

Meteorites, fossils valuable

Interplanetary dust particles, soil aggregates fragile

Diamonds, hard minerals time consuming

Studies of pore network : pore distribution, size, topography,

connectivity

Major Fields of Study

Earth and Environmental Research

High Pressure CMT (10 Gpa) Metal deposition in plant roots, minerals,

meteorites

Porosity Studies in Dehydraded-rehydrated media

Multi Phase Fluids in Porous Media

Attenuation of X-rays

Greater Attenuation

X-rays Sample

x

I = I0e-x

I0: Incoming intensity of X-rayI : Outgoing intensity of X-ray: linear X-ray attenuation

xI = I0e-(kxk..

X-ray Computed Microtomography (CMT) gives 3D images of the X-ray

attenuation coefficient .

Experimental Setup

Microscope Objective

CCD Camera

Rotation Stage

Sample

x Translation Stage

YAG Scintillator

X-rays

Visible LightMirror

Microtomography at APS Beamline 13-BMVarious stages align the

sample with the X-ray beam and CCD camera

YAG converts X-rays to visible light for imaging

System Under Investigation

Material

Silica beads pack in a cylindrical tube

Two different fluids containing I and Cs

Goal of Study

What ions exist in the fluid?

Where are the two types of liquids located?

What are their domain sizes and distributions

within the tube?

Data Processing – Image Reconstruction

I’ (x’, y’, Θ)

I (x, y, z)

Data Processing – X-ray AbsorptionI absorption edge Cs absorption edge

Conclusions

• CMT allows the identification of Soltrol® and aqueous CsCl in porous media.

• Aqueous CsCl is found in smaller amounts around inner wall of tube.

• X-ray tomography is a powerful and efficient tool for studying multiphase fluids in solids.

Acknowledgements

National School of Neutron and X-ray Scattering

DOE

Mark Rivers - University of Chicago, APS 13-BM Clinton Willson - Louisiana State University