Acta Physica Sinica, Volume. 69, Issue 10, 102902-1(2020)
X-ray scintillation screens as the core component of X-ray imaging detectors have widespread applications in the medical imaging, security inspection, high energy physics, radiochemistry, and so on. For a long time, the development of X-ray scintillation screen mainly focuses on improving the light yield in order to enhance its detection efficiency. However, a novel tendency has recently emerged for ultrafast time performance of the X-ray imaging detector. The indium doping zinc oxide (ZnO:In) with high radiation hardness, higher light yield(>10000 photons/MeV) and subnanosecond decay time is a promising scintillation material for ultrafast detections. In order to satisfy the requirements of X-ray scintillation screens with ultrafast and high-spatial-resolution in the existing and upcoming high energy physics experiments, the ZnO:In nanorod arrays have been prepared on a 100-nm-thick ZnO-seeded substrate by hydrothermal reaction method and then treated by hydrogen plasma in present work. The results of SEM demonstrate the average diameter and length of the ZnO:In nanorods are about 0.5 and 12 μm, respectively. The XRD shows the ZnO:In nanorods are highly aligned perpendicular to the substrate alongc-axis direction. The X-ray excited luminescence spectra show that two luminescence bands are observed, i.e. an ultraviolet emission peak located at about 395 nm and a visible emission band at 450–750 nm. It is particularly important to point out that hydrogen plasma treatment can enhance the ultraviolet emission of ZnO:In nanorod arrays and suppress its visible emission. The reason is attributed to the formation of shallow donors through hydrogen entering the ZnO and the combination of VO and Oi. In addition, the fluorescence decay times of the ultraviolet and visible emissions for the ZnO:In nanorod arrays are subnanosecond and nanosecond, respectively, satisfying the demand of the fast X-ray imaging. The spatial resolution of ZnO:In nanorod arrays has been characterized in X-ray imaging beamline at the Shanghai Synchrotron Radiation Facility. Under excitation of the X-ray beam with the energy of 20 keV, a system spatial resolution of 1.5 μm could be achieved by using an 12 μm thickness ZnO:In nanorod arrays as the scintillation screen, which is exceeded the highest level had ever been reported on ZnO:In nanorod arrays scintillation screen. In conclusion, this present work shows that it is a feasible solution for X-ray detection and imaging with high temporal and spatial resolution by using ZnO:In nanorod arrays as the X-ray scintillation screen.
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Qian-Li Li, Ya-Hua Hu, Yi-Fan Ma, Zhi-Xiang Sun, Min Wang, Xiao-Lin Liu, Jing-Tai Zhao, Zhi-Jun Zhang.
Category: Research Articles
Received: Feb. 25, 2020
Accepted: --
Published Online: Nov. 30, 2020
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