<title>Developments in synchrotron x-ray computed microtomography at the National Synchrotron Light Source</title>

Abstract

Last year, the X27A beamline at the National Synchrotron Light Source (NSLS) became dedicated solely to X-Ray Computed Microtomography (XCMT). This is a third-generation instrument capable of producing tomographic volumes of 1-2 micron resolution over a 2-3mm field of view. Recent enhancements will be discussed. These have focussed on two issues: the desire for real-time data acquisition and processing and the need for highly monochromatic beam (.1 % energy bandpass). The latter will permit k-edge subtraction studies and will provide improved image contrast from below the Cr (6 keV) up to the Cs (36 keV) k-edge. A range of applications that benefit from these improvements will be discussed as well. These two goals are somewhat counterproductive, however; higher monochromaticity yields a lower flux forcing longer data acquisition times. To balance the two, a more efficient scintillator for X-ray conversion is being developed. Some testing of a prototype scintillator has been performed; preliminary results will be presented here. In the meantime, data reconstruction times have been reduced, and the entire tomographic acquisition, reconstruction and volume rendering process streamlined to make efficient use of synchrotron beam time. A Fast Filtered Back Transform (FFBT) reconstruction program recently developed helped to reduce the time to reconstruct a volume of 150 x 150 x 250 pixels 3 (over 5 million voxels) from the raw camera data to 1.5 minutes on a dual R10,000 CPU. With these improvements, one can now obtain a "quick look" of a small tomographic volume (~l0 6 voxels) in just over 15 minutes from the start of data acquisition.

Shock induced damage in copper: A before and after, three-dimensional study

“…These radiographs were reconstructed with the GridRec algorithm to yield 625 crosssectional images at 1.48 lm resolution. 34,35 …”

High-resolution computed tomography in resin infused woven carbon fibre composites with voids

“…For SRCT, the sample was mounted vertically and orthogonal to the beam, with a propagation distance of 20 mm, allowing a degree of phase contrast to be achieved. The projections were collected through a rotation of 180˚ and 3-D reconstruction was achieved from the concatenated radiographs using an in-house code based on the GRIDREC/FFT approach [36]. Image analysis was performed using VG studio Max v2.1 TM and Avizo Fire 8 TM .…”

A comparative study of X-ray tomographic microscopy on shales at different synchrotron facilities: ALS, APS and SLS

“…Octopus software (Dierick et al, Figure 2 2004), which relies on a filtered backprojection algorithm, is normally employed at beamline 8.3.2 of the ALS. Beamline 2-BM of the APS and beamline TOMCAT of the SLS use their inhouse-developed applications with a code based on the Gridrec algorithm and fast Fourier transforms (Dowd et al, 1999;De Carlo & Tieman, 2004;Hintermü ller et al, 2010). Each software has its own advantages and disadvantages but the analysis of software is not the purpose of this study.…”