Laser initiaion of PETN-based composites with nano-sized absorbing additives of carbon and aluminum under conditions of various volume compression

The energy thresholds and the kinetics of explosive decomposition of pentaerythritol tetranitrate (PETN) and its composites induced by the laser pulse (λ0 = 1064 nm; τи = 12 ns) in dependence on the concentration of absorbing additives and different volume compression within the range from 40 to 600 MPa are experimen- tally studied. The sensitivity of pure PETN and its composites increases along with the volume compression value. For low pressures (less than 200 MPa) with the increase of additives concentration the sensitivity of mixtures to laser pulse exposure increases and for higher pressures (more than 300 MPa) — it decreases. Such behavior is explained from the perspective of both diffuse light scattering and the thermal micro-spot model of initiating the transparent explosive components (the “hot spot” model), according to which the reac- tive capacity of hot spots is determined by their heat reserve, their concentration and the scale of gas dynamic unloading in the neighboring to hot spots pores and through the sample surface pressed by the input window (the area of low pressures), as well as by the heat conducting unloading of hot spots in the explosive compo- nents matrix and the covering glass (the area of high pressures).