- The formation and temporal behavior of charged particles ensuing from the detonation of lead azide (LA) is studied. An ion probe tailored for measurements in the hostile environment produced following the detonation is described. The positive ions (most probably singly ionized lead atoms) and the electrons, which are simultaneously collected on separate electrodes, are embedded in the outer half of the expanding product cloud resulting from the detonation. They show similar temporal behavior and their maximum velocity is ∼4.5 km/s. The density of each of them at a distance of 2.5 cm from the LA sample is 4.3×1011–1.3×1012 cm-3 for detonation of 5–15 mg of LA, respectively. From the hydrodynamics of the expanding cloud and the density of the electrons, their temperature is estimated to be in the range 2600–3000 K. The results of the measurements are discussed in view of the mechanisms believed to govern the expansion of the product cloud following the detonation.