EPFL: high-resolution materials analysis with X-ray CT, with Gary Perrenoud

02 Nov 2022
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“With X-ray CT, it’s not necessary to prepare the sample, cut it or polish it – one scan gives us a complete mapping of the structure and defects of the sample in a fast and simple way.”
Gary Perrenoud, EPFL PIXE
UltraTom installed at EPFL
UltraTom installed at EPFL
X-ray CT is a powerful technology that lets you inspect and check all kinds of objects, even the most complex, simply and non-destructively.

It is an effective way to characterize the internal structure of objects non-destructively and to reconstruct complete 3D models. In materials analysis, CT has a wide range of applications: high-resolution microstructure analysis, defect analysis, fiber analysis, 4D inspection…
EPFL Campus © CC BY-SA 4.0
The École polytechnique fédérale de Lausanne (EPFL) combines research, teaching and innovation across its five multidisciplinary schools, with a focus on science and technology. 

At EPFL, X-ray CT is used by the ENAC Interdisciplinary Platform for X-ray micro-tomography (PIXE) for materials analysis, notably the study of soils and other geomaterials (concrete, rocks, plants), to understand soil components and how they evolve naturally.
With Gary Perrenoud from EPFL PIXE, we discussed the benefits of X-ray CT for materials analysis, the types of materials and analyses carried out, and the RX Solutions system used in their lab.

Can you introduce us to the main materials studied with X-ray tomography?

EPFL carries out research in many fields. Thus, we regularly study, within our PIXE platform, materials such as wood, concrete, rocks as well as composite materials. We also have the opportunity to scan insects, archaeological pieces, bones as well as mechanical parts. 
 
 
 Rhizome wood in 3D 
 
 

What is the main interest for EPFL to use X-Ray tomography ?

EPFL is a renowned school that trains engineers, especially in civil and materials engineering. X-ray CT allows us to characterize, with great precision, the different materials studied and developed here.
 
The versatility of the UltraTom, allows us to develop different experiment grounds to perform in-situ inspections and measurements. We currently have two units for tensile and compression tests. In one of them, we can also control humidity. We also have a unit for shear tests and plan to develop others in the near future thanks to UltraTom testing capabilities.

 

For which applications is X-Ray CT most effective ?

We are using X-ray CT more and more for in-situ testing. A laboratory of the EPFL, the CCLAB, regularly mandates us to perform in-situ tests. For example, in the images below (carousel of glassfiber images), we see a section of a composite material during a tensile test. This test allows us to see the deformation mechanics as well as the crack initiations in the material up to its breaking point, over time.


   
In-situ testing on a glassfiber With UltraTom - cracks over time 

 


What are the benefits of X-ray ct for material analyses?

The main benefits for us at EPFL are; the non-destructive aspect, the 3D visualization of the outside and inside of the sample as well as the possibility to do in-situ tests (4D inspection over time). Indeed, with X-ray CT, it is not necessary to prepare the sample, to cut it and to polish it like for a microscope analysis for example. It's easier and faster for us. In addition, X-ray CT gives us a complete mapping of the structure and defects of the sample.

What are the main sectors that use your expertise in X-ray CT?

The two main sectors are civil engineering and various material analyses. But over the years, sectors such as ecology, archaeology and life sciences have increasingly called on our services. We have also collaborated with a photographer, Catherine Leutenegger, on an exhibition called Unnaturale studies. This exhibition reveals the scientific and artistic potential of non-destructive imaging technology, in particular UltraTom, which unveils what cannot be seen with the naked eye. 
 
 "This intimate look into the geometry and microstructures of natural or artificial materials invites the spectator to travel inside matter and empty space, of which all things are made. Behind the apparent simplicity and the trivial nature of the objects collected, are hidden unknown worlds of fascinating complexity and intriguing beauty." 
 

The samples were taken from the Lake of Taillères and studies with UltraTom. More info about the exhibition  here. 
 

WHAT ARE THE MAIN SECTORS THAT USE YOUR EXPERTISE IN X-ray CT? 

The two main sectors are civil engineering and various material analyses. But over the years, sectors such as ecology, archaeology and life sciences have increasingly called on our services. We have also collaborated with a photographer, Catherine Leutenegger, on an exhibition called Unnaturale studies. This exhibition reveals the scientific and artistic potential of non-destructive imaging technology, in particular UltraTom, which unveils what cannot be seen with the naked eye.
 
"This intimate look into the geometry and microstructures of natural or artificial materials invites the spectator to travel inside matter and empty space, of which all things are made. Behind the apparent simplicity and the trivial nature of the objects collected, are hidden unknown worlds of fascinating complexity and intriguing beauty."
 
The samples were taken from the Lake of Taillères and studies with UltraTom. More info about the exhibition here.
 
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