Dynamic measurements of shock and detonation velocities are performed using long chirped fiber Bragg gratings (CFBGs). Such thin probes, with a diameter of typically 125 µm or even 80 µm can be directly inserted into high-explosive (HE) samples or simply glued laterally. During the detonation, the width of the optical spectrum is continuously reduced by the propagation of the wave-front, which physically shortens the CFBG. The light power reflected back shows a ramp-down type signal, from which the wave-front position is obtained as a function of time, thus yielding a detonation velocity profile. A calibration procedure was developed, with the support of optical simulations, to cancel out the optical spectrum distortions from the different optical components and to determine the wavelength-position transfer function of the CFBG. The fitted slopes of the X–T diagram give steady detonation velocity values which are in very good agreement with the classical measurements obtained from discrete electrical shorting pins (ESP). The main parameters influencing the uncertainties on the steady detonation velocity value measured by CFBG are discussed. To conclude, different HE experimental configurations tested at CEA (Commissariat à l’Energie Atomique et aux Energies Alternatives) are presented: bare cylindrical sticks, wedges for shock-to-detonation transitions (SDT), spheres, a cast-cured stick around a CFBG, and a detonation wave-front profile configuration.

The experiments have a key role in the initiation and transition studies of solid high explosives. Detonic has forced scientist to improve their experimental approach by designing relevant setup and developing accurate metrological devices. For example, the wedge or pop-plot test was developed in the 50's and remains a legacy experiment in the characterization of high explosive. However, for 70 years, it has been widely improved, because of the accurate measurements need. This paper aims to review the main improvements performed on the pop-plot test and analyze a series of results acquired on melt-cast and castcured high explosives. We first describe the current setup with its new metrological devices. Then, we discuss the results and limitations of this test.

Aluminum particles are usually added to plastic bonded explosives (PBX) in order to increase blast efficiency thanks to their post‐combustion with detonation products and air. These particles modify the shock to detonation (SDT) process of PBX. Their role has not been well understood. That is why, in this paper we proposed a review of the main hypotheses concerning aluminum particles effects on SDT. The main issue of thermal and mechanical equilibrium is discussed with the estimation of their impact on the Euler equations. This study also sums up the experimental data registered on RDX and HMX aluminized explosives. A comparison with a reference PBX is proposed and a new light on the mechanism of shock to detonation transition is given.