3D model of the sample holder plate with eight individual sample holders. On the left side, four sample holders are fully open and the cylindrical samples are shown in bright red for better visibility. On the right, the sequence of opening the sample holders is shown from closed (top) to open (bottom). The top of the sample holder, the piston, and the tool used for opening are removed before the measurement; they are shown semi-transparent. At the bottom left, the individual parts of the sample holder are shown. For the sample production, the sample holder is assembled and placed on a table with the opening pointing upward. The sample material is inserted into this opening followed by the piston. Then, the sample is compressed by placing a specific weight onto the piston. Lastly, the sample holder is rotated by 90 degrees and screwed onto the sample holder plate before being opened.