Dynamic micro-computed tomography (micro-CT) using monochromatic X-ray offers higher density resolution and lower radiation damage compared to that using white X-ray, however balancing its imaging spatial and temporal resolution is challenging. Currently, the reported highest temporal resolution of monochromatic X-ray dynamic micro-CT is 13.3 Hz with a detector effective pixel size of 5 μm.

This study aims to develop a monochromatic X-ray dynamic micro-CT system with a higher spatial and temporal resolution to meet the experimental needs of the fast X-ray imaging beamline (BL16U2) users at Shanghai Synchrotron Radiation Facility (SSRF).

Firstly, an experimental system of dynamic micro-CT with the high flux density monochromatic X-ray from an undulator source was established by combination of a high-speed rotary stage and a large numerical aperture triple-lens fast X-ray imaging detection system on the BL16U2 beamline at SSRF. Then, a demonstration experiment with a fast-foaming polyurethane material as a sample was performed to examine the spatial-temporal resolution of this experimental system, moreover a quantitative analysis of the bubble motion during foaming process was performed.

Experimental results of foaming process of the fast-foaming polyurethane material based on the monochromatic X-ray dynamic micro-CT system show that a temporal resolution of 20 Hz of the dynamic micro-CT was achieved with 15 keV monochromatic X-ray and an effective detector pixel size of 2.2 μm.

The developed monochromatic X-ray dynamic micro-CT system has a high spatial-temporal resolution and can perform four-dimensional quantitative analysis of complex motion systems, providing a powerful experimental research platform for users of BL16U2 beamline at SSRF.