LaB₆ Cathodes as an Alternative to W-Cathodes for High-Resolution Transmission X-Ray Tubes

A 240 kV microfocus transmission X-ray tube (XWT-240-TSC) incorporating lanthanum hexaboride (LaB₆) cathode technology is presented as a high-performance, application-driven alternative to conventional tungsten (W) cathode-based systems for highresolution X-ray imaging and computed tomography (CT) applications.The tube design is based on a compact single-stage focusing optic concept and a modular cathode platform, enabling flexible adaptation to different imaging requirements while maintaining a simplified system architecture.A direct experimental comparison between W and LaB₆ cathodes demonstrates that a medium-size LaB₆ cathode implemented in a single-stage system achieves improved spatial resolution compared to W-based single-stage systems and reaches resolution levels comparable to those of more complex double-stage designs.Sub-micrometer spatial resolution is achieved over a wide acceleration voltage range using both high-resolution and high-energy transmission targets.By controlled defocusing of the electron beam, target powers of up to 80 W are attainable.Long-term operation exceeding 3,000 hours confirms excellent thermal stability and a substantially extended cathode lifetime compared to tungsten cathodes.The results demonstrate that LaB₆ cathode technology enables high spatial resolution, high power capability, and long-term operational stability within a compact transmission X-ray tube design, making it particularly attractive for demanding industrial and scientific micro-computed tomography applications.