Thermionic enhanced heat transfer in x-ray tubes

Since their discovery in 1895, x-ray tubes have attracted enormous interest and have been intensively used in nondestructive inspection, medical imaging, and radiation therapy. However, the targets of x-ray tubes universally suffer from overheating problems since only 1% of the input energy is converted to x rays, and the remaining 99% is converted to heat. Thus, the overheating problem has severely restricted the development of high-power x-ray tubes. Here, we propose a method, e.g., thermionic cooling to enhance the heat transfer in x-ray tubes. By employing thermionic cooling, we found that the target temperature of x-ray tubes can be reduced from 1206 to 393 °C. Our results will pave the way for developing high-power x-ray tubes and, therefore, advance x-ray-based technologies.