Infrared spectrometry and radiometry of high-explosive detonations: the Los Alamos experiments

Abstract

The purpose of these experiments was to determine whether the infrared spectra of high-explosive detonations can be used to infer the type of explosive material and/or the containment material employed. Infrared spectra and radiometric traces were measured during a test series of twenty-three detonations; some were contained and some uncontained. A variety of high-explosive materials and containment materials were included. The explosive charge was typically about 175 g. Infrared spectra were taken at the rate of 250 spectra/sec. This rate was too slow to characterize the very early gas expansion or burn pase of these explosions. The infrared spectra of the delayed or afterburn phase of these explosions often displayed molecular emission and absorption features. Absorption by NH/sub 3/ was observed when C-4 was the high-explosive material, and not observed for any other material. Emissions from H/sub 2/O and CO/sub 2/ were observed part of the time. Their occurence does not seem to be correlated with the type of containment or type of high-explosive material, or peak temperature reached in the afterburn. From the radiometric traces, one concludes that the relative peak radiance from the burn and afterburn phases depend strongly on the type of high-explosive material. For similar devices the burn phase is consistent from shot to shot, whereas the afterburn is very inconsistent. The answer to the question whether infrared spectra of high-explosive detonations can be used to infer the type of explosive material and/or the containment material must await spectral observations of the burn phase. We now believe that spectra of the burn phase are likely to be the ones most useful in identifying the high-explosive or containment material.