High-resolution multi-MeV x-ray radiography using relativistic laser-solid interaction

Abstract

When high intensity (≥1019 W cm−2) laser light interacts with matter, multi-MeV electrons are produced. These electrons can be utilized to generate a MeV bremsstrahlung x-ray emission spectrum as they propagate into a high-Z solid target positioned behind the interaction area. The short duration (<10 ps) and the small diameter (<500 μm) of the x-ray pulse combined with the MeV x-ray spectrum offers an interesting alternative to conventional bremsstrahlung x-ray sources based on an electron accelerator used to radiograph dense, rapidly moving objects. In experiments at the Omega EP laser, a multi-MeV x-ray source is characterized consistently with number of independent diagnostics. An unfiltered x-ray dose of approximately 2 rad in air at 1 m and a source diameter of less than 350 μm are inferred. Radiography of a complex and high area density (up to 61 g/cm2) object is then performed with few hundred microns spatial resolution.

Z-scan confocal method for indirect focus location

“…2 Solid targets are also used to produce proton and ion beams, 3,4 X-rays and gamma beams. 5 In most of the schemes, electrons in the overdense plasma can accelerate ions as they leave the target on the rear side to produce high energy broadband ions. All these sources have remarkable properties and many proofs of principles have been developed to demonstrate the physics of these new sources.…”

Evaluating laser-driven Bremsstrahlung radiation sources for imaging and analysis of nuclear waste packages

“…Other authors have previously conducted studies to characterise x-ray emission from high-power laser solid interactions across a variety of laser systems [24,25], as well as radiography demonstration of the imaging qualities of the beams [26,27,28]. In the present experiment the x-ray beam demonstrated large divergence which permits a large field of view, thus providing a suitable foundation for the development of tomographic imaging of large objects.…”

Fast electron beam with manageable spotsize from laser interaction with the tailored cone-nanolayer target

“…The interaction of an ultrashort intense laser pulse with a solid target has been of considerable interest because of its many applications, such as in producing high-brightness K α and X-rays (Rousse et al, 2001), laser-driven accelerators (Eliezer, 2012), high-order harmonics generation (Teubner & Gibbon, 2009), high resolution radiography (Theobald et al, 2006;Courtois et al, 2011), fast ignition in inertial confinement fusion (Tabak et al, 1994), diagnostics of high energy density physics (Borghesi et al, 2002), etc. In general, the target configuration plays an important role in laserelectron energy conversion as well as the quality of the fast electron beams (FEBs).…”