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 du-
ration 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 intrinsic pulse duration of the X-ray emission is on the order of the
hot electron transit time, yielding femtosecond-scale temporal resolution.
The source is fully operational, stable at high repetition rate, and in-
trinsically 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 pro-
tein 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.
