Sensitization of PETN to laser radiation by opaque film coating

Laser ignitability of a two-component system constituted of a copper (II) oxide layer and a PETN (pentaerythritol tetranitrate) tablet was studied. An ytterbium fiber laser with 1070 nm wavelength, 20 ms pulse duration and 3.6 kW/cm2 power density was used. The threshold of launching of exothermic reaction as a function of the light absorbing coating layer thickness was studied. It has been found that the exothermic reaction zone formation does not always lead to the initiation of the entire sample. An analytical model describing the initiation of the exothermic decomposition reaction in the surface layer of the sample was developed. The effectiveness of the initiation of the explosion decreases with the increase in the thickness of the absorbing layer.