Laser Ignition And Initiation Of Energetic Materials

The present study is concerned with laser initiated detonator. The evaluation of different explosives and pyrotechnics has been done by using Nd: YAG 1064 nm pulsed laser.In order to manufacture the detonator first laser initiation of explosives and pyrotechnics was tried in unconfined state. But no success was achieved in direct initiation of the secondary explosives. Then the reasons of initiation failure were found after SEM analysis of the irradiated surfaces. It was found that absorbance of laser energy in energetic material, confinement, and ablation of irradiated material play an important role in initiation of secondary explosives. So the absorbance of explosives was improved by blending carbon black or boron. Then ablation of material was stopped by using a glass window for transmission of laser energy to the explosive surface, while confinement was achieved by using hermetically sealed detonator for ignition. After taking these measures the initiation of secondary explosives became easy.The experimental method for evaluation of laser initiation of different explosives and pyrotechnics in confined state has been found. Later different explosives including RDX, HMX, PETN, HNS, and NHN were successfully initiated.DSC analysis of HMX and RDX compositions has been done to evaluate the function of carbon. It was found that role of carbon as dopant in HMX and RDX is different. Threshold energies of NHN, B/KNO₃, 1 % carbon RDX and B/KNO₃ /Zr (40:50:10) have been tested by experimentation. The performance of 1 % carbon RDX as compared to 1% carbon HMX and HNS was found better. Testing of HMX and RDX having carbon content was done by placing the detonator on lead plate which was placed on the hard floor or on a hollow cylinder. A laser initiated detonator has been developed with an option of using different energetic material as per requirement.