Аннотация:The dependence of detonation parameters for (bis-(2-fluoro-2, 2-dinitroethyl) formal)/nitrobenzene solution (FEFO/NB) on NB concentration was defined. Velocity profiles of the boundary between HE and water window were recorded by laser interferometer VISAR. It was found that particle velocity in a pure FEFO was strongly oscillating with the oscillation amplitude ∼50 m/s. It means that detonation front is unstable and heterogeneities size is about 10 μm. The average velocity profile corresponds to ZND model. The reaction time is equal to ∼400 ns, C-J pressure and particle velocity are 24 GPa and 2.0 km/s respectively. For FEFO/NB solution it was found that at low NB concentrations (10-20%) oscillations disappeared and detonation front was stable. When the NB concentration increased up to 30% high-frequency oscillations appeared again. The measurements of reaction zone structure up to critical concentration were conducted, it was about 45%. At average particle velocity profiles Von Neumann spike was distinctly registered. It was shown that in a pure FEFO and in solutions with NB concentration exceeding 30%) detonation front was unstable.