This grant provides continued support for 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 non-living 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. Research applications spanning the geosciences, biology, engineering and anthropology are routinely supported. Data and images from UTCT scans are web-accessible data and extremely useful for teaching.
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The major goal of this project was the continued support of the University of Texas High-Resolution X-ray Computed Tomography Facility (UTCT) as a shared NSF multi-user facility in order to provide top-quality high-resolution X-ray CT data widely and inexpensively to the geological and wider scientific community. Industrial computed tomography (CT) is ideally suited for many geological applications, as it nondestructively creates 3D imagery of the interiors of rocks, fossils, meteorites and other materials. In this regard, during the 36-month period of the grant, we performed 5246 hours of invoiced scanning for 192 unique investigators, most of whom are earth scientists. We also provided free test scans to 65 investigators, in order to test the utility of CT for specific applications, or as proof-of-principle in support of planned grant proposals. NSF-supported scanning spanned seven programs: EAR, DEB, BCS, IIS, CHE, CCF, and EF. In addition, 13% of scanning hours were for commercial clients, providing them with access to our special capabilities and UTCT staff and students with experience in a wider range of practical applications of CT. Total invoicing for the three-year period was $1,046,873. Apart from providing our scanning services, we continuously improved our data quality, through improvements in instrumentation and software. On the instrumentation side, we augmented our Xradia microCT scanner by installing a full-rotation stage in August 2012, as well as a new detector and camera system (April 2013). We are currently in the process of a major upgrade to our other principal scanning system. These upgrades have allowed, or will allow, faster acquisition of higher-quality data. We continued to make incremental improvements to our Blob3D and Quant3D software for CT volume analysis, and to develop additional tools for reducing image artifacts. We have submitted for peer review manuscripts on our new algorithm for minimizing beam-hardening artifacts, and on a new tool for easily and objectively measuring scan resolution by determining a point-spread function (PSF) for most CT data sets. A measure of our success in providing access to CT imagery and sophisticated analysis and visualization tools for the scientific community is that our data is featured in 189 peer-reviewed papers either published or in press from 2010 until July 2013. Our data also contributed to 38 student theses and dissertations completed in 2010-2012. Some examples of scientific publications that have featured our data in the period from 2010 through 2013 are illustrated in figures 1-3. Our biological and paleontological data are also curated and disseminated on our Digimorph digital library (www.digimorph.org), which currently hosts approximately 1200 specimens (Fig. 4). We are nearing completion of a complete redesign of the "back end" of the Digimorph library, rewriting the databases and data-driven forms with up-to-date tools and platforms. We preliminarily plan to disseminate all UTCT data through this structure (currently we disseminate our data via ftp), though this will require further development effort. Digimorph.org had 161,505 unique visitors in 2012. The UTCT facilities are widely used by graduate and undergraduate students, including visiting students as well as those from the University of Texas. Students have been trained in 3D data processing and visualization, in support of their projects or projects or of supervising faculty. The UTCT has also hosted short-course workshops on the use of CT data for geological and paleontological projects. By providing state-of-the-art CT capabilities and maintaining open access to it, UTCT has enabled many researchers to obtain and analyze CT data.
