Multi-Fiber Fast Framing Camera for Vacuum Flashover Imaging

A multi-fiber framing diagnostic capable of capturing eight frames, covering a 2 ns window, in a single acquisition has been developed. Using beamsplitters, an image is split into eight paths, each of which is focused into a high-resolution fiber bundle containing 13,000 individual fibers. Free space and fiber propagation lengths are chosen such that each of the eight paths is progressively delayed by a nominal 250 ps. The outputs of the fibers are focused onto an intensified CCD camera, such that eight temporally staggered images are captured simultaneously in a single gating of the camera. After development and calibration, the camera was fielded on the Caeculus flashover testbed and used to capture sequential images of an anode-initiated flashover event spanning from the first detectable light through the impedance collapse of the gap.
Supported by the LDRD program at SNL. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.