Characterization of Dual-Mode Scintillators for Fast Neutron and X-ray Radiography

X-rays and neutrons serve as sources for various radiographic applications, and scintillators for use with each are well-established. While high-energy X-ray radiography is useful for applications involving high-Z materials, this technique is limited for probing objects with low-density composition. Alternatively, fast neutron radiography can be used for detecting low-Z compositions without significant attenuation by dense materials. By combining fast neutrons and X-rays in a single radiographic application, the complementary information provided by each source can be used to produce images with more information about a subject. Currently, there are no commercially available detectors capable of high-resolution imaging with both fast neutrons and X-rays. Under sponsorship through the DOE/NNSA’s Office of Defense Nuclear Nonproliferation, RMD is developing a high-resolution radiography detector for both high-energy X-ray and fast neutron imaging. The envisioned detector maximizes detection efficiency for fast neutrons and high-energy X-rays, while also producing high-contrast radiographs with sub-mm spatial resolution. Multiple scintillator formats for use in a dual-mode detector have been developed including 1) Embedded ZnS converters, 2) Layered CsI converters, 3) Tin-loaded Organic Glass Scintillators, and 4) Pixelated Organic Glass Scintillators. These scintillators have produced X-ray radiographs with spatial resolutions below 100 µm and fast neutron radiographs with spatial resolutions as low as 550 µm. Here we report on imaging data collected with these dual-mode scintillators using separate fast neutron and X-ray sources.