Active and Passive Optical Fiber Metrology for Detonation Velocity Measurements

Abstract

The reaction rate of an explosive – also called detonation velocity – is the easiest parameter to measure, and also one of the most important in characterizing the process of detonation front propagation in a 1D approach. This paper presents some peculiarities that were observed during the testing of our passive/active optical methods to measure detonation velocity. Both methods were tested using bare optic fiber probes and optic fiber probes protected with a stainless steel tube. The active optical method uses a laser with a wavelength of 660 nm, and the recording system contains a window filter that blocks any radiation outside the wavelength range of 650 to 665 nm. A plastic-bonded explosive based on PETN (seismoplast) was used to test both experimental methods. For rectangular cross-section charges using the passive optical method with the two different probes, the detonation velocities obtained ranged from 7233 to 7324 m/s, with standard deviations between 1.1 and 6.0 %; for the active optical method, the experimental results for detonation velocity varied between 7261 and 7351 and were obtained with a standard deviation of 0.6 to 1.7 %.