Description
We report on a compact laser-driven plasma X-ray source developed and operated at ELI Beamlines for time-resolved diffraction, spectroscopy, and imaging applications. The source is based on the interaction of an ultrashort near-infrared laser (central wavelength λ ≈ 800 nm, pulse duration τ ≈ 30–50 fs) with solid targets at intensities in the range of 10^17–10^19 W/cm2. Under these conditions, hot electrons with characteristic temperatures described by ponderomotive scaling are generated, reaching typical values of Th∼5–20 keV depending on laser intensity.
These hot electrons penetrate into the target bulk and induce inner-shell ionization, leading to characteristic Kα emission. The resulting X-ray source exhibits photon energies tunable via target material (e.g., Cu:8.0 keV, Mo: 17.4 keV, Ti: 4.5 keV), with conversion efficiencies on the order of 10^−5–10^−4 into Kα radiation. The photon yield reaches up to 10^10–10^11 photons/sr/shot, depending on laser and target conditions.
The source is fully operational, stable at high repetition rate, and intrinsically synchronized with the driving laser, making it ideally suited for pump–probe experiments. We have experimentally demonstrated X-ray diffraction capabilities, including powder diffraction from ionic crystal powders and initial measurements on small single crystals, including protein crystals. Building on these results, we are implementing a pump–probe platform where the optical laser serves as the pump and the plasma generated Kα radiation acts as the probe. The system will be commissioned for time-resolved powder diffraction and extended to studies of superlattices, single crystals, and protein crystallography.
This approach enables direct investigation of ultrafast lattice dynam-
ics, non-equilibrium phase transitions, and structural evolution in con-
densed matter systems. The combination of micrometer source size, fem-
tosecond duration, high photon flux, and compact geometry positions this
source as an alternative to large-scale X-ray facilities for ultrafast science.
