  We report an original method allowing to recover the temporal profile of any
kind of soft X-ray laser pulse in single-shot operation. We irradiated a soft
X-ray multilayer mirror with an intense infrared femtosecond laser pulse in a
traveling wave geometry and took advantage of the sudden reflectivity drop of
the mirror to reconstruct the temporal profile of the soft X-ray pulse. We
inferred a pulse shape with a duration of a few ps in good agreement with
numerical calculations and experimental work.
