A 24 keV liquid-metal-jet x-ray source for biomedical applications

We present a high-brightness 24-keV electron-impact microfocus x-ray source based on continuous operation of a heated liquid-indium/gallium-jet anode. The 30-70 W electron beam is magnetically focused onto the jet, producing a circular 7-13 μ m full width half maximum x-ray spot. The measured spectral brightness at the 24.2 keV In K α line is 3 × 10 9 photons/(s × mm 2 × mrad 2 × 0.1% BW) at 30 W electron-beam power. The high photon energy compared to existing liquid-metal-jet sources increases the penetration depth and allows imaging of thicker samples. The applicability of the source in the biomedical field is demonstrated by high-resolution imaging of a mammography phantom and a phase-contrast angiography phantom.