Broadband Terahertz Analysis of Energetic Materials—Influence of Crystal Structure and Additives

A detailed broadband analysis of energetic materials using THz time-domain spectroscopy with a bandwidth from 0.2 to 6.4 THz is presented. Dependencies of the resonance features on different sample parameters are evaluated via spectroscopic investigation of several energetic materials (TNT, C4, RDX, PETN, AN) in transmission and reflection experiments. A strong dependency of the resonance features on the manufacturing process of an explosive is observed especially with TNT. The THz measurements of the TNT samples are compared to powder X-ray diffraction measurements. Furthermore, it is observed that additive compounds with a flat frequency response offset the THz reflection of an explosive, but the recognition capability of a resonance feature is not influenced.