Acquisition Modes


Radiography

Radiography produces two-dimensional (2D) projection images by measuring the attenuation of X-rays as they pass through a sample. At BMIT, radiographic imaging capabilities extend beyond conventional absorption-based techniques to include specialized contrast methods. The BMIT-BM beamline offers analyzer-crystal-based radiographic imaging with 20 μm pixel resolution, leveraging the exceptional stability of its Si[2,2,0] monochromator crystals for ultra-small-angle scattering contrast through rocking curve imaging. This technique has proven particularly valuable for studying lung diseases and testing therapeutic interventions. Both beamlines support K-edge subtraction imaging, which exploits the sharp absorption changes at elemental absorption edges to enhance contrast for specific materials, as demonstrated in studies of lead fragmentation patterns in hunting ammunition.

Computed Tomography

Computed tomography (CT) makes use of computer-processed combinations of many X-ray projections taken from different angles of a sample to produce cross-sectional (tomographic) images of specific areas of the sample, which provides three-dimensional (3D) structural information of the scanned sample. CT is available at BMIT and can combine with any imaging techniques at BMIT, such as absorption-CT, phase-contrast-CT, DEI-CT, Spectral KES-CT. 

The unique capabilities at BMIT also include live animal CT, with successful in vivo imaging of animals as large as dogs achieved with 54 μm voxel resolution. BMIT is one of the few synchrotron beamlines in the world for live animal imaging and the only one in North America. The BMIT-ID beamline provides exceptionally large beam cross-sections (110 mm × 6 mm usable area at 100 keV) enabling tomographic imaging of samples up to one meter in length, while supporting high-energy monochromatic CT up to 140 keV for penetrating dense materials. Spatial resolutions range from 150 μm down to 0.36 μm depending on detector configuration, with acquisition times from sub-hour to multi-day depending on sample requirements and resolution needs.

Helical Acquistion

BMIT is capable of helical acquisition through its continuous rotation capabilities and motorized vertical positioning systems. The beamlines can perform helical scanning by combining continuous sample rotation with simultaneous vertical translation, allowing for volumetric coverage of extended samples that exceed the detector's field of view height. Some of the benefits of helical acquisition is the reduction of ring artifacts, which is particularly valuable for visualizing low-density samples, and provides more uniform X-ray exposure which enables imaging with lower radiation doses while maintaining good image contrast and spatial resolution.

Dynamic and Time Resolved Acquisition

BMIT is capable of dynamic computed tomography (dynamic CT) using synchrotron radiation for investigating temporally evolving internal structures non-destructively. This technique uses sub-second data acquisition speeds (down to 1 ms per X-ray projection and a complete CT in 500 ms) made possible by the superior X-ray photon flux from synchrotron sources, enabling capture of processes that occur on the order of several seconds. Dynamic CT uses continuous sample rotation, acquired in buffered mode in a dedicated high-speed camera memory. Dynamic CT is capable of quantitatively analyzing rapid microstructural evolution non-destructively and no sample modification.

Computed Laminography

BMIT supports comptued laminography imaging through goniometer-equipped positioning systems on both beamlines. Laminography is a specialized tomographic technique that uses tilted-axis rotation geometry, making it particularly suitable for imaging flat, plate-like, or laterally extended samples that would be difficult to orient optimally for conventional tomography. The BMIT-BM beamline incorporates a goniometer within its sample positioning system with 90 mm vertical travel range, while BMIT-ID utilizes a Kappa geometry goniometer mounted on the large animal positioning system. This capability expands the range of sample geometries that can be effectively imaged in three dimensions at the facility.