Precision stress measurements in severe shock-wave environments with low-impedance manganin gauges

We describe new techniques that permit the use of low-impedance manganin stress gauges in chemically reacting shock waves in the 1.0--40.0 GPa range. The rugged, small, and fast response gauge has reproducibility better than 2% when used in conjunction with a pulsed bridge circuit and adjustable, current-regulated power supplies. Techniques are presented for fabricating the transducer package, calibrating the bridge circuit and oscilloscopes, designing the drive system, and reducing the data. Data are presented for planar impact experiments performed with a 102-mm gas gun on high-explosive samples. In particular, we directly measured the Chapman-Jouquet pressure in the explosive RX03-BB [92.5% triaminotrinitrobenzene (TATB)/7.5% polychlorotrifluoroethylene (Kel-F binder)] as 28.2 +- 0.6 GPa. These new developments open the possibility of applying low-impedance manganin gauges in chemically reactive hydrodynamic flows such as the evolution of a shock wave into a detonation wave