Shock initiation of the tri-amino-tri-nitro-benzene based explosive PBX 9502 cooled to −55 °C

We report a series of shock initiation experiments on PBX 9502 cooled to −55 °C. PBX 9502 consists of 95% dry aminated tri-amino-tri-nitro-benzene (TATB) and 5% poly-chloro-trifluoro-ethylene5 (Kel-F 800) binder. PBX 9502 samples were shock initiated by projectile impact from a two stage gas gun. Buildup to detonation was measured with 10 or more particle velocity gauges embedded at different depths in the sample. Three shock wave trackers measured the position of the shock front with time. Particle velocity vs. time wave-profiles and coordinates for onset of detonation were obtained as a function of the impact stress or pressure. PBX 9502 sample temperatures were monitored using type-E thermocouples, two inside the sample and two on the sample surface. Additional thermocouples were mounted on other parts of the cooling apparatus. Wave profiles from embedded gauges are qualitatively similar to those observed at 23 °C. However, at −55 °C, PBX 9502 is much less sensitive than at 23 °C. For example, at an inpact stress of 15.4 GPa, the distance to detonation at −55 °C is 7.8 mm. At 23 °C, the distance is 4.3 mm.