X-ray Transparent Barrels for Exploding Foil Initiators

Little is known about the shape and curvature of exploding foil initiator (EFI) flyers, especially as they are forming within a finite barrel. This is because the typical barrel materials, such as stainless-steel, hinder observation of the flyer material during flight. Here we report a new capability for imaging EFI flyers within X-ray transparent barrels by using thin-walled aluminum or polycarbonate. We show that the change in confining material to aluminum does not perturb the flyer produced by the EFI through image comparison and velocity calculations. We found that polycarbonate barrels changed the flyer shape but did not affect the flyer velocity. This highlights the importance of imaging for understanding the spatial characteristics of an EFI. These results provide unprecedented fidelity and resolution for in situ X-ray profile imaging of EFI flyers as they form within a barrel.