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Book: Tomography of Soil-Water-Root Processes
Published by: Soil Science Society of America, American Society of Agronomy, and Crop Science Society of America



  1.  p. 29-41
    SSSA Special Publication 36.
    Tomography of Soil-Water-Root Processes

    S. H. Anderson and J. W. Hopmans (ed.)

    ISBN: 978-0-89118-931-2


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Industrial X-Ray Computed Tomography Applied to Soil Research

  1. J. S. Steude,
  2. F. Hopkins and
  3. Jeffrey E. Anders
  1. Scientific Measurement Systems, Austin, Texas
    Rockwell International, Canoga Park, California


Nondestructive measurements of soil properties using computed tomography (CT) have been extensively utilized over the past decade. The properties measured have included: bulk density, porosity, water content, solute concentration, macropore size, and fracture width. Several porous media flow processes have also been monitored and quantified with CT measurements. The majority of the published results have been generated with medical CT scanners utilizing low energy, low resolution x-ray sources. In some cases, researchers have constructed custom CT scanners with gamma-ray sources. We present CT images obtained with industrial CT scanners equipped with high energy and high resolution (microfocus) x-ray sources. To demonstrate high energy CT, a large diameter (572 mm) sand sample was imaged before and after wetting. Image subtraction was used to isolate the x-ray attenuation due to the presence of water. The high resolution capability was demonstrated by generating 500 images of a small diameter (5 mm) sandstone sample. These images have spatial resolution on the order of 0.010 mm. These images clearly show the sizes and shapes of the grains and pores. The representative CT images presented demonstrate that CT measurements can be generated on scales spanning several orders of magnitude.

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Copyright © 1994. Copyright © 1994 by the Soil Science Society of Agronomy, Inc., 5585 Guilford Rd., Madison, WI 53711 USA