Computed Tomography

We have been running a µCT since 2008. From the beginning, it has been designed for high resolutions and soft materials. In 2014, the device underwent a major upgrade. It now features a fully accessible cabin, particularly well-suited for in-situ experiments.

Moreover, a second detector has been installed, that was originally designed for medical applications. It is highly sensitive to the low energies usually applied to image materials with low X-ray absorption.

Equipment

X-Ray Emitting Tube

  • Feinfocus FXE 225 (max acceleration voltage 225 kV, max power ~20 W)

 

Detectors

  • PerkinElmer detector with 2048 x 2048 pixels
    for high energy imaging (usable up100 kV to 225 kV acceleration voltage)
  • Thales detector with 3072 x 3072 pixels
    for low energies (usable from 40 kV to 160 kV)

The finest nominal resolution of the CT system is 0.8 µm, the coarsest about 100 µm.

Computed tomography at the Fraunhofer ITWM
© ITWM

Computed tomography at the Fraunhofer ITWM

Typical Materials

  • metal foams, ceramic foams, poly-urethane foams
  • other porous materials like non-woven, paper, wood-based insulation materials
  • glass fiber reinforced composites, carbon fiber reinforced composites
  • leather
  • concrete and mortar

Of course we measure other materials, too.

In the following we show some examples of reconstructed CT images taken with our tomograph:

PMI rigid foam. Evonik Rohacell WIND-F RC100. Pixel edge length 2.8µm.
© ITWM

PMI rigid foam. Evonik Rohacell WIND-F RC100. Pixel edge length 2.8µm.

Biscuits roses de Reims. Pixel edge length 13 µm.
© ITWM

Biscuits roses de Reims. Pixel edge length 13 µm

Steel fiber reinforced concrete, crack after 4 point bending test. Pixel edge length 77µm.
© ITWM

Steel fiber reinforced concrete, crack after 4 point bending test. Pixel edge length 77µm

Sample Size at Desired Resolution

Thales detector:

  • desired resolution in µm x 10³ x 2 = edge length of the square sample base or
  • desired resolution in µm x 10³ x 2.5 = diameter of the base of the cylindrical sample

 

PerkinElmer detector:

  • desired resolution in µm x 10³ = edge length of the square sample base or
  • desired resolution in µm x 10³ x 1.5 = diameter of the base of the cylindrical sample

 

Example:

desired resolution 1µm required under the use of the Thales-Detektors  2 mm edge length or 2.5 mm diameter with a cylindrical sample