Absolute timing of laser-driven radiation sources interacting in matter

A major challenge facing the study of radiation in matter on ultrafast time scales is the need for an absolute timing reference. Typically, these type of experiments are performed using pulses of ions from radio frequency accelerators which have nanosecond scale pulse durations and timing jitter making high temporal resolution measurements difficult to achieve. Here, we show that a combination of a highly synchronised probe pulse with a muti-species laser-driven radiation source can allow for the absolute timing of radiation in matter. This is primarily due to the generation of a X-ray calibration fiducial enabling the study of ion-induced dynamics in matter on ultrafast timescales.