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

When high intensity (>= 10(19) 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 mu m) 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 mu m are inferred. Radiography of a complex and high area density (up to 61 g/cm(2)) object is then performed with few hundred microns spatial resolution. (C) 2011 American Institute of Physics. [doi:10.1063/1.3551738]