Liquid-metal-jet x-ray sources and high-resolution biomedical imaging*

The power and brightness of electron-impact micro-focus x-ray tubes have long been limited by thermal damages to the anode. We pioneered a new anode concept, liquid-metal jets. This regenerative anode allows operation with electron-beam-power densities several orders of magnitude higher than with stationary or rotating anodes. Present liquid-metal-jet tubes typically rely on room-temperature liquid-metal alloys and operate with a 4-20 μm spot size in the 20-160 kV range with up to one order of magnitude higher brightness than state-of-the-art x-ray micro-focus tubes. The liquid-metal-jet sources are now commercially available by Excillum. We will describe the principles as well as recent developments of these high-brightness sources.

The high brightness enables a wide range of applications in diffraction, scattering, and imaging. In biomedical imaging we exploit the source properties for high spatial resolution and high contrast. Typically, we employ propagation-based phase contrast and combine with tomographic reconstructions for 3D imaging. Examples include studies of whole animals (mouse, zebrafish), organs (lungs, muscles), microvasculature (kidney, ear, tumors), and virtual histology (human coronary arteries). The source enables observation of cellular, and in some cases subcellular, detail within the context of the whole organ, animal, or specimen.