Manganin Gauge and Reactive Flow Modeling Study of the Shock Initiation of PBX 9501

A series of 101mm diameter gas gun experiments was fired using manganin pressure gauges embedded in the HMX-based explosive PBX 9501 at initial temperatures of 20 C and 50 C. Flyer plate impact velocities were chosen to produce impact pressure levels in PBX 9501 at which the growth of explosive reaction preceding detonation was measured on most of the gauges and detonation pressure profiles were recorded on some of the gauges placed deepest into the explosive targets. All measured pressure histories for initial temperatures of 25 C and 50 C were essentially identical. Measured run distances to detonation at several input shock pressures agreed with previous results. An existing ignition and growth reactive flow computer model for shock initiation and detonation of PBX 9501, which was developed based on LANL embedded particle velocity gauge data, was tested on these pressure gauge results. The agreement was excellent, indicating that the embedded pressure and particle velocity gauge techniques yielded consistent results.