Pulsed laser irradiation of a nanoparticles sensitised RDX crystal

Abstract

The laser initiation of secondary explosives presents tactical, safety and environmental advantages over traditional ignition systems utilising primary explosives. In this paper, direct ignition or initiation by pulsed laser was investigated of cyclotrimethylenetrinitramine (RDX) crystals doped with gold nanoparticles (GNPs) for the first time. A nano-seconds pulsed laser was used for direct irradiation of the crystals at the GNP's surface-plasmon-resonance wavelength of 532 nm. RDX crystals were recrystallised from a solution containing GNPs and characterised by visual microscopy for surface coating and subsurface doping. A high-speed camera was used to observe and capture the modes of interaction between the GNPs-doped RDX crystals and pulsed laser irradiation with a new classification method. Laser fluence thresholds for ignition and initiation were established. The GNPs sensitized RDX to pulsed laser irradiation at this selected wavelength is 3 orders of magnitude more sensitive than pure RDX. Direct initiation of the GNPs doped RDX crystal at laser fluence of 0.04 J/cm2 led to the total consumption of a crystal sample, which was unreproducible with pure RDX. The results show that GNPs are effective optical sensitizers for direct initiation of RDX crystal by low-power pulsed laser.