Active and Passive Optical Fiber Metrology for Detonation Velocity Measurements

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 %.