Method for VoD measurement on spherical charges

Abstract. Detonation velocity is a fundamental parameter for characterizing explosive materials. It can be measured relatively easily along the surface of charges with elongated geometries - such as cylinders, detonating cords, or sheets. Difficulties arise, however, when detonation velocity must be determined in bulk charges initiated internally, for example in spherical charges with a centrally placed detonator. In these cases, surface-based measurements are not feasible, and some degree of intrusion into the charge becomes necessary. Yet drilling multiple probe holes with varying depths builds on the expectation, that the detonation wave is diverging in perfect symmetry from the center of the charge, which cannot be guaranteed. Thus, while minimizing intrusions is beneficial for maintaining undisturbed detonation conditions, obtaining sufficiently dense and reliable data typically requires numerous measurement points. To reconcile these competing requirements, this work proposes the use of a perforated optical-fiber probe for detonation-velocity measurements in spherical charges. This approach enables the acquisition of a large number of datapoints through a single drilled channel, thereby reducing disturbance to the charge while still providing high-resolution temporal and spatial information on the detonation wave.