Shock experiments using thin wafer or foil impactors: an impulsive test capability for gas gun

Typical spall experiments on gas guns use moderately thick impactors and samples to tailor the wave propagation and produce a region of maximum tensile stress in a material. For energy absorbing materials which will be subjected to impulsive loading, such as in a pulsed reactor, this can result in failure to qualify a material at conditions where they would survive under regular application. We describe a technique developed to enable launch of <200 µm thick sapphire wafers or metal foil impactors on gas gun facilities. Peak stresses induced in a sapphire reference agree with experiments using bulk material impactors and steady pulse widths were ~40 ns FWHM. An experiment using these impactors to test a shock absorbing material is shown.