Proton radiographic and numerical of colliding, diverging PBX-9502 detonations.

The Proton radiographic shot PRAD0077 was designed to study the interaction of colliding, diverging PBX-9502 detonations. The shot consisted of a 50 mm by 50 mm cylinder of PBX-9502 initiated on the top and bottom at the axis by a SE-1 detonator and a 12 mm by 12 mm cylinder of 9407. Seven radiographs were taken at times before and after the detonation collision. The system was modeled using the one-dimensional SIN code with C-J Burn in plane and spherically diverging geometry and using the two-dimensional TDL code with C-J Burn and Forest Fire. The system was also modeled with the recently developed AMR Eulerian reactive hydrodynamic code called NOBEL using Forest Fire. The system results in a large dead or nonreactive zone as the detonation attempts to turn the corner which is described by the model using Forest Fire. The peak detonation pressure achieved by the colliding diverging detonation is 50 gpa and density of 3.125 mg/ml which is about the same as that achieved by one-dimensional spherically diverging 9502 detonations but less than the one-dimensional plane 9502 peak colliding detonation pressure of 65 gpa and density of 3.4 mg/ml. The detonation travels for over 10 mm before it starts to expand and turn the corner leaving more than half of the explosive unreacted. The resulting diverging detonation is more curved than a one-dimensional spherical diverging detonation and has a steeper slope behind the detonation front. This results in the colliding pressure decaying faster than one-dimensional colliding spherical diverging pressures decay. The calculations using Forest Fire reproduce the major features of the radiograph and can be used to infer the colliding detonation characteristics

<title>Synchro-ballistic recording of detonation phenomena</title>

Synchro-ballistic use of rotating-mirror streak cameras allows for detailed recording of high-speed events of known velocity and direction. After an introduction to the synchro-ballistic technique, this paper details two diverse applications of the technique as applied in the field of high-explosives research. In the first series of experiments detonation-front shape is recorded as the arriving detonation shock wave tilts an obliquely mounted mirror, causing reflected light to be deflected from the imaging lens. These tests were conducted for the purpose of calibrating and confirming the asymptotic Detonation Shock Dynamics (DSD) theory of Bdzil and Stewart. The phase velocities of the events range from ten to thirty millimeters per microsecond. Optical magnification is set for optimal use of the film`s spatial dimension and the phase velocity is adjusted to provide synchronization at the camera`s maximum writing speed. Initial calibration of the technique is undertaken using a cylindrical HE geometry over a range of charge diameters and of sufficient length-to-diameter ratio to insure a stable detonation wave. The final experiment utilizes an arc-shaped explosive charge, resulting in an asymmetric detonation-front record. The second series of experiments consists of photographing a shaped-charge jet having a velocity range of two to nine millimeters per microsecond. To accommodate the range of velocities it is necessary to fire several tests, each synchronized to a different section of the jet. The experimental apparatus consists of a vacuum chamber to preclude atmospheric ablation of the jet tip with shocked-argon back lighting to produce a shadow-graph image

Synchro-Ballistic Recording of Detonation Phenomena

Synchro-ballistic use of rotating-mirror streak cameras allows for detailed recording of high-speed events of known velocity and direction. After an introduction to the synchro-ballistic technique, this paper details two diverse applications of the technique as applied in the field of high-explosives research. In the first series of experiments detonation-front shape is recorded as the arriving detonation shock wave tilts an obliquely mounted mirror, causing reflected light to be deflected from the imaging lens. These tests were conducted for the purpose of calibrating and confirming the asymptotic Detonation Shock Dynamics (DSD) theory of Bdzil and Stewart. The phase velocities of the events range from ten to thirty millimeters per microsecond. Optical magnification is set for optimal use of the film`s spatial dimension and the phase velocity is adjusted to provide synchronization at the camera`s maximum writing speed. Initial calibration of the technique is undertaken using a cylindrical HE geometry over a range of charge diameters and of sufficient length-to-diameter ratio to insure a stable detonation wave. The final experiment utilizes an arc-shaped explosive charge, resulting in an asymmetric detonation-front record. The second series of experiments consists of photographing a shaped-charge jet having a velocity range of two to nine millimeters per microsecond. To accommodate the range of velocities it is necessary to fire several tests, each synchronized to a different section of the jet. The experimental apparatus consists of a vacuum chamber to preclude atmospheric ablation of the jet tip with shocked-argon back lighting to produce a shadow-graph image

Proton radiography examination of unburned regions in PBX 9502 corner turning experiments

PBX 9502 Corner Turning Experiments have been used with various diagnostics techniques to study detonation wave propagation and the boosting of the insensitive explosive. In this work, the uninitiated region of the corner turning experiment is examined using Proton Radiography. Seven transmission radiographs obtained on the same experiment are used to map out the undetonated regions on each of three different experiments. The results show regions of high-density material, a few percent larger than initial explosive density. These regions persist at nearly this density while surrounding material, which has reacted, is released as expected. Calculations using Detonation Shock Dynamics are used to examine the situations that lead to the undetonated regions