The customized XRCT scanner is designed for in-situ reactive flow-through experiments within an ETHZ-built shielding enclosure (with a controlled temperature) in Room B86 in the NW building of ETHZ. The scanner is equipped with an adjustable X-ray tube up to 130 kVp and a spot size of 5 μm at a power of 4-39W, and a CMOS flat panel detector with structured CsI scintillator of 2940×2304 pixels, providing a nominal scanning resolution down to 2.5 μm, depending on the scanner’s Field of View (FOV). The current FOV is from 7 to 90 mm, with an upgrade potential to a larger FOV. The current variable FOV delivers a 2D-image matrix from 512×512 to 8192×8192 pixels. One of the novel designs of the scanner is that it has a horizontally-rotating gantry (where the X-ray tube and the detector sit), allowing 180° and 360° rotation for stacking and multiple scanning (either centered or offset). To ensure high precision rotation stability, the gantry is supported by an air bearing. The scanned samples can be mounted on the Z-axis (the vertical rotation axis of the gantry), which enables a scanning length of 400 mm for integrated, calibrated (helical) scanning. The scanner is controlled by a workstation outside the shielding enclosure. The volumetric reconstruction is accelerated by a dedicated GPU.