Scintillating Quantum Dots May Hold the Key to High-Speed, Low-Cost X-Rays
Imagine if capturing an x-ray was as fast and simple as taking a digital photo. Now imagine being able to capture high speed radiography videos with the same relative ease.
Exploring quantum dots for x-ray imaging is opening the door to lower-cost, high-resolution radiography devices with greater portability than ever before. These materials rapidly fluoresce under x-ray radiation, enabling researchers to visibly observe and record radiography images.
Eric Burke, a mechanical engineer at NASA Langley Research Center and Office of Safety and Mission Assurance Nondestructive Evaluation program manager, is leading agency efforts to advance Microstructured Scintillating Quantum Dots for Imaging X-Rays (SQDIX). Scintillating Quantum Dots (StQDs) are nano-scale particles that convert x-ray energy into visible light.
StQDs use existing visible-light optics and digital cameras for x-ray inspection, which greatly reduces production cost. Current state-of-the-art radiography panel production is dependent on difficult processing methods. Use of StQDs will greatly reduce this cost while increasing the quality of the final detector. Additionally, StQDs do not require power to operate, other than the x-ray, and StQD-coated materials are easily transportable.
Phase 1 testing conducted at Langley’s Nondestructive Sciences Branch characterized StQDs for use as an imaging scintillator and has demonstrated the feasibility of using StQDs to produce x-ray images. The second phase of testing included fluorescence characterization of StQDs-based nanocomposites in terms of quantum efficiency, spectral emission, fluorescent emission decay times and dependence on temperature. Burke and his team filed for a patent for “Device and Method of Scintillating Quantum Dots for Radiation Imaging” in August 2016 [Patent # US20160231440 A1].
Fluorescent emission decay times were found to be incredibly short, potentially forming the basis of an effective method for high-speed radiography.
X-ray imaging is a critical inspection method universally used to detect flaws in aerospace materials and structures. Once matured, SQDIX has the potential to greatly improve NASA’s versatility in applying radiography inspection methods. SQDIX technology will directly affect aircraft x-ray inspection methods for both metals and composites, enabling radiography inspection of in-service parts used in tight spaces with very high-speed x-ray radiography and enhancing the x-ray resolution capabilities beyond the current technology. Considered together, these characteristics may have the potential to revolutionize radiography imaging similar to how digital photography has largely replaced film.
Due to the increased sensitivity of the SQDIX system, the time required for exposure to ionizing radiation will be reduced. Therefore, in medical radiography imaging, the amount of exposure to the patient would be kept to a minimum, resulting in greater patient safety.
Implementation of these cross-cutting technologies will have far-reaching effects from aerospace vehicle safety applications to the medical community. The use of StQDs as a functionalized radiography detection system has the potential to greatly exceed current capabilities in the x-ray imaging and detection field and will have game-changing impacts across many fields, including the Department of Energy, Department of Defense, NASA, medical imaging fields and aircraft inspection.