APPARATUS FOR THE MASS-SPECTROMETRIC ANALYSIS OF DETONATION PRODUCTS QUENCHED BY ADIABATIC FREE EXPANSION

We describe an apparatus that enables mass spectral analysis of the reacting chemical mixtures that drive detonation. Laboratory-scale (approximately 0.1 g) explosive pellets are detonated in a high-vacuum chamber and rapid cooling by adiabatic free expansion quenches the chemical reactions. The instrument records a series of 95 mass spectra of the quenched reaction mixtures from one pellet. The spectra cover the mass range m = 1 to m = 300 and are recorded every 12 mus, which provides a mass analysis for every 20 mum of the detonation wave. This expansion of the time scale occurs because after expansion a 20-mum layer takes 12 mus to pass the mass spectrometer ionizer. The series of spectra give a molecular characterization of the chemical processes that drive detonation.