LPXS: a high-performance, recirculating liquid-metal laser-plasma x-ray source

A Laser-Driven Plasma X-ray Source (LPXS) can provide intense, hard X-rays in femtosecond pulses emitted from a micrometer-size spot on a recirculating liquid-metal target. Unlike X-ray tubes based on electron beams, which are subject to constraints of the electron optics and space-charge effects, there is no fundamental limit to the amount of laser power that can be concentrated into the micrometer focus. With the increasing availability of industrial picosecond and femtosecond laser systems it now is practical to offer high average X-ray flux, combined with far higher brilliance and far shorter pulses than possible with X-ray tubes. Because the laser target in an LPXS is a liquid-metal, each laser shot encounters a fresh surface. Metal vapor and droplets are collected and recirculated to the target metal pump for maintenance-free operation. Hard X-rays are generated at tens of keV photon energies consisting of continuum radiation and, depending on the target material composition, of Ga-K, Bi-K or In-K emission lines.