Development of multiframe time-gated x-ray backlighting for the Z Facility using multile laser pulse produced plasma x-ray source.

X-ray radiography is a standard diagnostic used on the Z Facility to measure the dynamics of target implosions. The multi-kJ Z-Beamlet Laser (ZBL) system is used to create a pulsed x-ray source which backlights an experiment recorded on image plate. ZBL can create two angle-multiplexed laser beams that are focused to separate target positions inside the Z vacuum chamber. There is a desire to increase the number of images captured per shot, ideally from an identical angle to follow the evolution of features that can vary from shot to shot.



The present generation of Sandia’s Ultrafast X-ray Imager (UXI) high-speed digital x-ray framing cameras are able to operate successfully in the Z vacuum chamber and can replace image plate as the backlighting detector. A UXI camera’s ability to record multiple images on a few nanosecond time scale and along a single line-of-sight makes it feasible to increase the number of radiographs per shot by generating multiple x-ray pulses per laser beam. However, this requires additional source development, which we have begun and are reporting on.



A potential roadblock to realizing multi-frame backlighting with multiple laser pulses is that the interaction of subsequent laser pulses with the x-ray target is uncertain. We have empirically studied this effect with ZBL and identified a set of laser and target parameters to create multiple x-ray pulses of sufficient fluence for radiography on Z. We will present the latest results from fielding UXI cameras on Z as time-gated backlighting detectors both for suppression of target self-emission in radiograph images and for obtaining extra frames.