Frequently Asked Questions:
What is the sample size?
The ideal sample shape is cylindrical; however, irregular shapes are also acceptable. During scanning, the sample is rotated over a 180° range. In the case of a cylindrical sample, the projected thickness remains consistent at every angle.
The sample size should fit within the field of view (FOV) of the chosen magnification. For example, if using the White detector, the sample diameter should correspond to the horizontal size indicated by the red circle below.
Lower magnification allows for larger samples, but sufficient X-ray transmission must still be ensured, especially for larger and dense specimens. For low-density samples, the sample size can slightly exceed the FOV. For instance, with an 18× objective, a slightly larger than 1 mm diameter sample is suitable if the material is of low density.
Scanning only a region of interest (ROI) within a larger sample is generally discouraged, as it may compromise reconstruction quality. For larger specimens, stitching techniques may be employed to extend the effective FOV, but users should be aware that this significantly increases the reconstructed dataset size. As a reference, a single tomographic dataset without stitching is typically on the order of ~50 GB.
What is the best resolution on the MCT beamline?
The highest achievable resolution on the MCT beamline is approximately 1–2 µm. A nano-CT system is not yet available. Although the detector pixel size can be reduced to 0.325 µm, the actual spatial resolution is influenced by additional factors, including X-ray source size, scintillator thickness, numerical aperture, and overall optical performance. The image below shows a resolution test pattern acquired using the highest magnification setting of the MCT detector.
How to mount a powder sample?
There are several ways to mount powder samples, and new ideas are welcome.
How to view parameter values in the metadata?
How to view the data size?
