Initial experiments with monochromatic X-ray imaging by X pinches on the cobra accelerator

Summary form only given. The COBRA accelerator is a pulsed power generator capable of producing up to 1 MA current pulses. The machine is driven by two 60 kJ Marx generators that feed four parallel pulse-forming lines that are merged into a single wire-array Z-pinch load. A typical pulse rise time is 100 ns and the pulse width is about 200 ns. Time-gated X-ray imaging is an important diagnostic for the study of imploding dense Z-pinches. These rapidly changing plasmas must be studied on the nanosecond time scale, and they generally radiate strongly in the soft X-ray range. As such, they require short, intense X-ray sources to illuminate them. Monochromatic X-ray imaging using an X pinch X-ray source is a way that has been used successfully in the past. On COBRA, X-pinches in return current rods in the Z-pinch load region are used as the time-gated X-ray source. Monochromatic imaging is provided by reflecting X pinch radiation off of a spherically bent mica crystal. Experiments have been performed to investigate X-ray source parameters including source size and X-ray spectrum for various materials and configurations. These results will be the main focus of this presentation