Instruments Microtomography

For this experiment, as well as for the microtomography ( 3.2) we used the commercial desktop microtomography system Skyscan 1072 [5], the setup of which is sketched in Figure 1. For this instrument, which is designed to study relatively large objects with a diameter up to 50 mm, the source size is 8 pm, the distance source-detector is about 50 cm and the effective resolution of the detector is about 80 pm. For this system and this object, the global effective resolution a is estimated to be of the order of 50 to 100 pm [6]. 

Successful development of such systems will lead to foamed materials having useful stress-absorbing characteristics in addition to controlled physics properties. Although our work in this area is currently in a very early stage, prototype materials have been successfully synthesized and assessed structurally using three-dimensional (3D) X-ray microtomography. The technique offers a unique insight into the internal microstructure of cellular materials (see Fig. 3). The diameter of the mainly open cell pores varies from approximately 100 to 250 pm (the resolution of the instrument is 5 pm), with cell walls of variable thickness. 

In this chapter, we discuss synchrotron X-ray microprobe and microtomography instrumentation, practical aspects of pXRF, pXAFS and microtomography, and examples of applications to earth and environmental materials. Other discussions of synchrotron-based microprobe and microtomography techniques can be found in the following references Dunsmuir et al. 1991 Janssens et al. 1993 Sutton et al. 1994 Schulze and Bertsch 1995 Smith and Rivers 1995 Jones et al. 1997 Sutton and Rivers 1999 Rivers et al. 1999 Bertsch and Hunter 2001 Baker 2002. 

Sutton SR, Rivers ML (1999) Hard X-ray synchrotron microprobe techniques and applications. In Synchrotron Methods in Clay Science. CMS Workshop Lectures Vol. 9. Schulze DG, Stucki JW, Bertsch PM. (eds). The Clay Mineral Society, Boulder CO, p 146-163 Sutton SR, Flynn G, Rivers M, Newville M, Eng P (2000) X-ray fluorescence microtomography of individual interplanetary dust particles. Lunar Planet Sci XXXI 1857 Sutton SR, Rivers ML, Bajt S, Jones KW, Smith JV (1994) Synchrotron X-ray-fluorescence microprobe-a microanalytical instrument for trace element studies in geochemistry, cosmochemistry, and the soil and environmental sciences. Nucl Instrum Methods Phys Res A 347 412-416 Suzuki Y, Awaji M, Kohmura Y, Takeuchi A, Takano H, Kamijo N, Tamura S, Yasumoto M, Handa (2001) X-ray microbeam with sputtered-shced Fresnel zone plate at SPring-8 undulator beamline. Nucl Instrum Methods Phys Res A 467-468 951-953... 

With provision for projected high magnification, the beam-line area is relatively extensive and can accommodate a range of ancillary equipment. This attribute makes the laboratory microtomography facility a very versatile instrument. It can operate in a variety of modes and support scanning strategies that arc tailored to particular subject shapes, sizes, and material content. With large-area... 

Ge Wang, S. Zhao, and P. Cheng, Exact and Approximate Cone-Beam X-ray Microtomography, Modem Microscopies (I)—Instrumentation and Image Processing, World Scientific, Singapore, 1998. 

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