Electron-Impact Liquid-Metal-Jet Hard x-Ray Sources

The power and brightness of electron-impact microfocus x-ray sources have long been limited by thermal damage in the target. This is a major constraint for a wide range of biomedical applications, from imaging to diffraction. Here, we describe the development of an x-ray microfocus source based on a new target concept, the liquid-metal jet (LMJ). The regenerative nature of this target allows for significantly higher e-beam power density than on conventional targets, resulting in this source showing promise for > 100 × higher brightness than state-of-the-art sources. We first discuss the basic physics of the two important subsystems of the source, LMJ in vacuum and focused electron-beam systems, and then describe the properties of several versions of the source, from early prototypes to the first LMJ sources now reaching the market. Finally, we review some early applications of the source for biomedical imaging and diffraction.

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