Validation of the Contrast Attenuation Technique (CAT) for Deducing Dust Densities from Photographic Records Taken during the MILL RACE High Explosive Test

摘要

The MILL RACE high explosive test was used to validate the Contract Attenuation Technique for deducing dust densities by measuring the reduction in contract between an object and its background. A total of six movie cameras were placed at the 10 psi and 20 psi distance from GZ along with six photo targets at each location. Movies were obtained from just before the detonation to up to 5 minutes after and showed passage of the dust cloud as it enveloped the cameras and targets until the air was essentially free from dust. The films were processed according to standard techniques and the resulting data analyzed on both a diffuse and microdensitometer. Application of the Contract Attenuation Technique produced a set of dust density vs time data which were compared with sampled measurements taken at MILL RACE in the same location and at the same time. The results showed agreement to a factor of 2.4 + or - 0.61 seconds of data.