L-241 Booster Reliability Test Matrix Preliminary Report
December 2018Elizabeth Francois (Stokes Fellow)
An explosive booster is the second step in the initiation train. Its purpose is to spread the energy input from the detonator into a fully detonating divergent wave, capable of initiating the main charge. Boosters can be challenged by the inherent features of the main charge which may be insensitive, slow to run to detonation, have asymmetric wave propagation, and be hampered by cold temperature. Booster reliability is the focus of this project as it pertains to size, geometry and temperature effects. Because there are so many main charges available, and the scope of this paper is to develop a protocol for booster reliability, the booster will largely be evaluated by itself. The understanding being, if it performs well in a standalone test: exhibiting CJ pressure states, CJ velocity states, divergence and wave spreading, the initiation of the main charge will be consistent.
Boosters can run the gamut of highly sensitive: PBX 9407 (Gibbs & Popolato, 1980) to very insensitive: ultrafine TATB (UFTATB). The size, shape and material of a booster are chosen as the best option for initiating the main charge. The order when designing a weapon is usually selection of the main charge, selection and testing of the booster capable of lighting the main charge. The detonator choice is usually limited to an existing fielded detonator.
Reliability, with respect to boosters, is a measure of the ability to light the main charge in the given size and shape at the given temperature. Some materials are notoriously temperature sensitive. The cold temperature performance of TATB and its’ formulations is legendary for its challenges (Gibbs & Popolato, 1980). Because of this, the reliability of explosives at low temperatures (as low as -54oC) is critical to ascertain. This project proposes a suite of tests that examine the parameters relevant for symmetric, reliable initiation, performance and booster capability at cold temperatures.