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Lens-coupled X-ray computed tomography (X-ray CT) using a transparent scintillator imaged on a CCD camera obtains higher spatial resolution than the more commonly employed phosphor-enhanced amorphous silicon (A-Si) panels. A-Si panels are limited to resolution typically greater than ~200 microns, have a limited working life due to degradation with dose, and provide intrinsically low efficiency with thin (few hundred microns thick) phosphor coatings. Demanding applications such as imaging the interior of complex additively manufactured components require high throughput and high resolution, best achieved with a lens-coupled system. However, for large fields-of-view, very large area but thin transparent scintillators are required – a format difficult to fabricate with high light yield single crystals – therefore, glass scintillators with both modest X-ray interaction and light yield have been used for years. We have developed a new polycrystalline transparent ceramic scintillator, Gd0.3Lu1.6Eu0.1O3, or “GLO,” that offers excellent stopping power and light yield for improved contrast in sizes up to 14” x 14” plates, with thicknesses in the 2-10 mm range, and we are implementing it in systems to increase imaging throughput for 9 MeV Bremsstrahlung X-ray CT. CT imaging performance will be described.

Fast neutron Computed Tomography (nCT) is a powerful and non-invasive imaging modality that can be used to examine features and defects within low Z elements (such as plastic) hidden or shielded by high Z elements (such as tungsten, lead, or even stainless steel). This study built a fast neutron radiography and nCT system and explored various multi-material complex objects utilizing a fast neutron beam at The Ohio State University Research Reactor (OSURR), which provides ~5.4 x 10^7 n·cm-2·s-1 neutron flux at 1.6 MeV (median energy). The lens-based system includes an Electron Multiplying (EM) CCD camera, a light-tight enclosure, and a high light yield 1 cm thick Polyvinyl Toluene (PVT) scintillator provided by Lawrence Livermore National Laboratory (LLNL). A variety of test exemplars were scanned, with the number of projections for each scan ranging from 90 to 180, covering either 180 or 360 degrees. The exposure time for each projection ranged down to one minute, enabling a full nCT scan within a few hours of operation at a 500-kW low power research reactor. 3D tomograms were constructed using Octopus reconstruction software. Results showed that not only could nCT projection data be successfully constructed into volume data, but good contrast between HDPE and a millimeter-sized tungsten ball could be obtained. The 3D tomography presents high contrast to clearly discern HDPE features and voids inside tungsten shielding that are not discernable using 2D radiography.