Detection of high explosive detonation across material interfaces with chirped fiber Bragg gratings

Measuring detonation wavefront position and velocity changes across material interfaces has been demonstrated using an all-optical chirped fiber Bragg grating approach. An experiment was conducted with a cylindrical rate stick consisting of multiple high explosive (HE) segments. A measurement of detonation position across interfaces of different HE formulations was made for both low and high spatial resolution gratings. The results show the accuracy of measured velocities is increased with the higher resolution gratings. A decaying shock driven into the polymethyl methacrylate (PMMA) segment provided a measure of the minimum internal fiber pressure required for prompt grating destruction and accurate wavefront position measurement.