CC BY 4.0 UnportedHoltz, MarcelHauf, ChristophWeisshaupt, JannickSalvador, Antonio-Andres HernandezWoerner, MichaelElsaesser, Thomas2023-06-052023-06-052017https://oa.tib.eu/renate/handle/123456789/12404http://dx.doi.org/10.34657/11436Table-top laser-driven hard x-ray sources with kilohertz repetition rates are an attractive alternative to large-scale accelerator-based systems and have found widespread applications in x-ray studies of ultrafast structural dynamics. Hard x-ray pulses of 100 fs duration have been generated at the Cu Kα wavelength with a photon flux of up to 109 photons per pulse into the full solid angle, perfectly synchronized to the sub- 100-fs optical pulses from the driving laser system. Based on spontaneous x-ray emission, such sources display a particular noise behavior which impacts the sensitivity of x-ray diffraction experiments. We present a detailed analysis of the photon statistics and temporal fluctuations of the x-ray flux, together with experimental strategies to optimize the sensitivity of optical pump/x-ray probe experiments. We demonstrate measurements close to the shot-noise limit of the x-ray source.enghttps://creativecommons.org/licenses/by/4.0/530500Electron sourcesLaser pulsesOptical pumpingPhotonsStructural dynamicsX-ray apparatusX-raysArticle