X-ray imaging with grazing-incidence microscopes developed for the LIL program

This article describes x-ray imaging with grazing-incidence microscopes, developed for the experimental program carried out on the Ligne d’Intégration Laser (LIL) facility [J. P. Le Breton et al. , Inertial Fusion Sciences and Applications 2001 (Elsevier, Paris, 2002), pp. 856–862 ] ( 24 kJ , UV— 0.35 nm ). The design includes a large target-to-microscope ( 400 – 700 mm ) distance required by the x-ray ablation issues anticipated on the Laser MégaJoule facility [P. A. Holstein et al. , Laser Part. Beams 17, 403 (1999)] ( 1.8 MJ ) which is under construction. Two eight-image Kirkpatrick-Baez microscopes [P. Kirkpatrick and A. V. Baez J. Opt. Soc. Am. 38, 766 (1948)] with different spectral wavelength ranges and with a 400 mm source-to-mirror distance image the target on a custom-built framing camera (time resolution of ∼ 80 ps ). The soft x-ray version microscope is sensitive below 1 keV and its spatial resolution is better than 30 μ m over a 2 - mm -diam region. The hard x-ray version microscope has a 10 μ m resolution over an 800 - μ m -diam region and is sensitive in the 1 – 5 keV energy range. Two other x-ray microscopes based on an association of toroidal/spherical surfaces (T/S microscopes) produce an image on a streak camera with a spatial resolution better than 30 μ m over a 3 mm field of view in the direction of the camera slit. Both microscopes have been designed to have, respectively, a maximum sensitivity in the 0.1–1 and 1 – 5 keV energy range. We present the original design of these four microscopes and their test on a dc x-ray tube in the laboratory. The diagnostics were successfully used on LIL first experiments early in 2005. Results of soft x-ray imaging of a radiative jet during conical shaped laser interaction are shown.