Time-resolved optical measurements of the post-detonation combustion of aluminized explosives

Abstract

The dynamic observation and characterization of light emission following the detonation and subsequent combustion of an aluminized explosive is described. The temporal, spatial, and spectral specificity of the light emission are achieved using a combination of optical diagnostics. Aluminum and aluminum monoxide emission peaks are monitored as a function of time and space using streak camera based spectroscopy in a number of light collection configurations. Peak areas of selected aluminum containing species are tracked as a function of time to ascertain the relative kinetics (growth and decay of emitting species) during the energetic event. At the chosen streak camera sensitivity, aluminum emission is observed for 10μs following the detonation of a confined 20g charge of PBXN-113, while aluminum monoxide emission persists longer than 20μs. A broadband optical emission gauge, shock velocity gauge, and fast digital framing camera are used as supplemental optical diagnostics. In-line, collimated detection is determined to be the optimum light collection geometry because it is independent of distance between the optics and the explosive charge. The chosen optical configuration also promotes a constant cylindrical collection volume that should facilitate future modeling efforts.