Bremsstrahlung emission from high power laser interactions with constrained targets for industrial radiography

Laser-solid interactions are highly suited as a potential source of high energy X-rays for non-destructive imaging. A bright, energetic, x-ray pulse can be driven from a small source, making it ideal for high resolution x-ray radiography. By limiting the lateral dimensions of the target we are able to confine the region over which x-rays are produced, enabling imaging with enhanced resolution and contrast. Using constrained targets we demonstrate experimentally a (20 ± 3) µm x-ray source, improving the image quality compared to unconstrained foil targets. Modelling demonstrates that a larger sheath field envelope around the perimeter of the constrained targets increases the proportion of electron current that recirculates through the target, driving a brighter source of x-rays.