Catastrophic processes in dielectrics in irradiation by high-current electron beams

Electric breakdown and explosive decomposition of PETN monocrystals initiated by electron beam

“…The obtained results show evidence for the elec tric discharge mechanism of PETN initiation by HEB that was described in [3,6,7]. Microexplosions in the zones of electric discharge initiation lead to fracture of a monocrystal, gas dynamic unloading of the products of evaporation and chemical decomposition products in to the free space, and further expansion of the major part of unreacted substance.…”

“…According to the former mechanism, the explosion develops from so called "hot spots," the role of which is played by the channels of electric breakdown. This hypothesis is based on indirect experimental data gained from investigations of physicochemical pro cesses in explosives [2,3,6,7] and electric breakdown in passive (nonexplosive) dielectrics under the action of HEBs [8][9][10]. According to the latter mechanism, the key role belongs to electron-hole excitations (free electrons, holes and excitons) formed in PETN under irradiation.…”

Initiation of furazanotetrazinedioxide and mixes on its basis by high-current electron beam

“…Analyse of results of FTDO initiation by electron beam proves that initiation model can be based on electronic discharge model published in [5][6][7][8][9]. Particularly the evidence of this is dimensional effect discovered in the presented work.…”

“…If we take H* equal to 0.1 J/cm 2 , take into account FTDO heat capacity that is equal to 1 J/g·K and its density of 1.5 g/cm 3 and take into account that electrons are being absorbed in 0.04 cm thick layer, all this will give average layer heating of 2.2 K. That is to say, here is the same situation as with the electron initiation of HMA where thresholds of explosive decomposition are laying in the range of 0.1 J/cm 2 [5]. In [5,6] a model of "hot centers" formation in volume of EM during localization of energy evolved as a result of electric breakdown was suggested for description of HMA behavior. At sufficiently high rates of the reaction of chemical decomposition the process may develop out of the region of energy release of electron beam and expand on the whole mass of explosive.…”

Explosion initiation of furazanotetrazine dioxide by a high-current electron beam

“…When taking into account that the specific heat capacity of FTDO is c ~ 1 J/g K, while the electron absorption occurs in a layer of 320 μm, the excited vol ume average of the temperature increases at H* = 0.09 J/cm 2 and the homogeneous distribution of ion ization losses of the FTDO energy is approximately 2 K, which contradicts the thermal mechanism of ini tiation. Approximately the same situation occurs as at the electron beam initiation of azides of heavy metals (AHMs), where explosive transformation thresholds are in a range of ~0.1 J/cm 2 [6,7]. To describe the behavior of AHMs and pentaerythritol tetranitrate (PETN) upon irradiation by an HCEB, we [6][7][8][9] pro posed an electric discharge model of occurrence of "hot points" in the explosive volume during localiza tion of energy released as a result of the electrical breakdown.…”