X-ray sources have important applications in medical diagnosis, industrial inspection, etc. Transparent X-ray source has not been reported before, which enables the applications such as simultaneous imaging using X-ray and visible light. In this article, a fully vacuum-encapsulated transparent flat-panel X-ray source was prepared by using ZnO nanowires cold cathode and indium-tin-oxide (ITO) transmission anode. The effect of thicknesses of ITO film on X-ray radiation intensity was studied. A radiation dose rate of 6.85 mGy/s measured at 5 cm in front of the flat-panel X-ray source (FPXS) under 48-kV anode voltage and an optical transmittance of 72.63% at 550-nm light were achieved. X-ray spectra show the indium is the main element to generate the X-ray. By adopting the device in an X-ray and visible light dual-functional inspection set-up, the X-ray and visible light imaging of objects were demonstrated simultaneously.

Talbot-Lau grating interferometer (GI) can provide valuable tri-contrast (absorption, differential phase contrast, and dark field) information about the samples to be imaged. However, the source grating G0 presents severe challenges associated with fabrication and limited efficiency. In this study, a novel cold-cathode flat-panel X-ray source with microarray anode target was proposed for GI computed tomography, which can eliminate the use of G0. Its cathode is characterized as densely arranged ZnO nanowires (NWs) to provide large amounts of electrons, whereas the micro periodic distributed Al-Mo-Al strips were utilized as the anode target to generate the structured X-ray illumination required for Talbot-Lau GI. The performance of the source was fully studied by accurately modeling its geometry via EGSnrc. The flat-panel X-ray source GI computed tomography was then simulated by utilizing Fresnel-Kirchhoff diffraction theory. Furthermore, a PMMA cylinder and a Shepp-Logan phantom were utilized to evaluate the imaging performance of the system. Due to the elimination of G0, our proposed flat-panel source GI has 153.05% higher X-ray photons utilization efficiency than the conventional Talbot-Lau GI, which results in tri-contrast images with less noise. The proposed X-ray source can replace the lab source and grating G0 and may provide new possibilities for Talbot-Lau GI.

A novel reflective anode flat-panel X-ray source using ZnO nanowire cold cathode and a metal anode has been developed. Simulation analysis indicated that the reflective anode structure reduces electric field concentration compared to a transmission anode structure. The current–voltage characteristics, X-ray radiation dose rate, and stability of the fabricated device were thoroughly characterized. The device demonstrated a maximum emission current of 481.1 μA and a maximum radiation dose rate of 303 μGy/s at an anode voltage of 40 kV. The X-ray imaging of various objects was also conducted. Our findings are of significance for developing high-performance, robust flat-panel X-ray sources for diverse applications.

Cold cathode flat-panel X-ray source (FPXS) holds promising applications in compact imaging, radiation therapy, food disinfection, and so on. Achieving uniform and high brightness emission is essential for realizing these applications. In this work, we demonstrate that uniform emission from a ZnO nanowire cold cathode FPXS operated under high power, larger than 200W. To realize high-power operation, the device uses liquid cooling to mitigate anode heat buildup. Experimental results confirm that this approach successfully achieves a high power of 201W in DC mode and 284.4W in pulsed mode. A maximum surface dose rate of 9.64Gy/min was achieved at DC anode voltage of 50kV. A significant improvement in uniformity was observed when the device operated under higher current, which is attributed to the self-ballasting effect inherent to the semiconductor ZnO nanowire emitters. A theoretical simulation of the self-ballasting effect was carried out, and the results fit well with experimental ones. High emission uniformity of 84.1% was achieved for the FPXS device. Furthermore, the high-power FPXS has successfully demonstrated both static and dynamic projection imaging capabilities. Our results are important for realizing the practical application of FPXS technology.