Facility Support: High-Resolution X-ray Computed Tomography Laboratory

University Of Texas At Austin, Austin TX

Investigators

Abstract

1258878 Ketcham This Division of Earth Sciences Instrumentation and Facilities Program grant supports continued operation of the University of Texas Computed X-ray Tomography (UTCT) Facility over a three year period. The CT scanner at UT was specifically designed to enable x-ray tomography of a range of geological materials and sample sizes. The technology was developed from commercial biomedical CAT scanners with the adoption of a higher energy x-ray source and higher resolution CCD detectors to allow micron-scale imaging of geological samples. The technique allows for completely non-destructive imaging of the exteriors and interiors of samples. Differences in x-ray attenuation that occur due to variations in sample density and the elemental composition of the material along the x-ray path are digitally recorded by a CCD. Samples are mounted on a rotating table in front of the x-ray source. Radial 2-d slices of the attenuated x-rays are stacked by vertical translation of the sample table. Resultant x-ray ?sinograms? are then reduced via computer algorithms to render high resolution 3-D images of the density distributions within samples. A ongoing upgrade of the UTCT high energy system will increase both resolution and scanning speed, lowering costs for lab clients and opening a multitude of new research possibilities. In particular, it will enable ?4D? scanning of systems in motion (during fluid flow, cooling, heating, strain, etc.). Exploration and exploitation of these new capabilities for an expanded range of studies including studies of fluid flow through fractured and porous media with relevance to groundwater hydrology, hydrocarbon reservoir extraction enhancement and carbon dioxide subsurface sequestration will be enabled by this renewal award. Continued support will benefit a large and diverse set of research constituencies. Over the last two years , UTCT has served 194 principal investigators, most of whom are Earth scientists spanning the full breadth of subdisciplines, including petrology, paleontology, structural geology, hydrology, meteoritics, and economic and petroleum geology. UTCT's clientele also includes many researchers in other fields, principally biology, engineering, and anthropology. Three-quarters of investigators were from outside the University of Texas. The facility will continue to support user training through developed short courses and assist users in data reduction routines. ***