In situflash x-ray high-speed computed tomography for the quantitative analysis of highly dynamic processes

Abstract

The in situ investigation of dynamic events, ranging from car crash to ballistics, often is key to the understanding of dynamic material behavior. In many cases the important processes and interactions happen on the scale of milli- to microseconds at speeds of 1000 m s−1 or more. Often, 3D information is necessary to fully capture and analyze all relevant effects. High-speed 3D-visualization techniques are thus required for the in situ analysis. 3D-capable optical high-speed methods often are impaired by luminous effects and dust, while flash x-ray based methods usually deliver only 2D data. In this paper, a novel 3D-capable flash x-ray based method, in situ flash x-ray high-speed computed tomography is presented. The method is capable of producing 3D reconstructions of high-speed processes based on an undersampled dataset consisting of only a few (typically 3 to 6) x-ray projections. The major challenges are identified, discussed and the chosen solution outlined. The application is illustrated with an exemplary application of a 1000 m s−1 high-speed impact event on the scale of microseconds. A quantitative analysis of the in situ measurement of the material fragments with a 3D reconstruction with 1 mm voxel size is presented and the results are discussed. The results show that the HSCT method allows gaining valuable visual and quantitative mechanical information for the understanding and interpretation of high-speed events.

Review of Microfluidic Devices and Imaging Techniques for Fluid Flow Study in Porous Geomaterials

“…In addition, 4D X-ray CT extends X-ray imaging to assess and visualize dynamic processes, such as multiple phase flow and solute transport in pores structures, with sufficient spatial and temporal resolutions, especially on the scale of milli- to microseconds [ 200 , 201 , 202 , 203 , 204 ]. The result of 4D imaging is a series of uninterrupted 3D images of the internal structure of the material during a dynamic process of interest as a function of time [ 204 , 205 ].…”

“…The concept of dynamic imaging has been used in the past and in-situ devices such as micromodel visualization and viewing cells have been developed to achieve temporal analysis of different process at pores structures. However, in order to obtain 4D images for some high-speed events, a custom experimental set-up is required [ 202 , 204 , 208 ]. One of the essential requirements in fluid flow experiments, is the size and composition of the sample holder which confines the sample [ 208 ].…”

3-D scanning of sea freight containers using MeV X-rays

“…2. Furthermore three reconstruction methods were compared, namely a standard filtered back projection (FBP) [3] and two iterative algebraic reconstruction techniques (an algorithm based on AVMART by Fraunhofer EMI called EMI-ART [4], and a compressed sensing (CS) method by Fraunhofer EZRT based on [5] and [6]). FBP is very fast and efficient and allows starting to reconstruct from the first projection during the scan.…”

In-Situ High Resolution Dynamic X-ray Microtomographic Imaging of Olive Oil Removal in Kitchen Sponges by Squeezing and Rinsing

“…Alternatively, micro magnetic resonance imaging (MRI) can provide dynamic fluid tracking on compressed foam structures; yet, with poor spatial and temporal resolution [ 16 ]. In recent years, an increasing interest has extended X-ray imaging to the temporal dimension [ 17 ]; exploiting the non-destructive nature of μCT to assess dynamic processes of pores structures such as visualizing multiple phase flow and solute transport in real-time [ 14 , 18 , 19 ]. Accordingly, μCT was chosen as the ideal technology to track soil removal over MRI.…”