High-resolution x-ray monochromatic imaging for laser plasma diagnostics based on toroidal crystal

Monochromatic x-ray imaging is an essential method for plasma diagnostics related to density information.Large-field high-resolution monochromatic imaging of a He-like iron(Fe XXV)Kαcharacteristic line(6.701 keV)for laser plasma diagnostics was achieved using a developed toroidal crystal x-ray imager.A high-index crystal orientation Ge(531)wafer with a Bragg angle of 75.37°and the toroidal substrate were selected to obtain sufficient diffraction efficiency and compensate for astigmatism under oblique incidence.A precise offline assembly method of the toroidal crystal imager based on energy substitution was proposed,and a spatial resolution of 3-7μm was obtained by toroidal crystal imaging of a 600 line-pairs/inch Au grid within an object field of view larger than 1.0 mm.The toroidal crystal x-ray imager has been successfully tested via side-on backlight imaging experiments of the sinusoidal modulation target and a 1000 line-pairs/inch Au grid with a linewidth of 5μm using an online alignment method based on dual positioning balls to indicate the target and backlighter.This paper describes the optical design,adjustment method,and experimental results of a toroidal crystal system in a laboratory and laser facility.

High-resolution Mo KαX-ray monochromatic backlight imaging using a toroidal crystal

Curved crystal imaging is an important means of plasma diagnosis.Due to the short wavelengths of high-energy X rays and the fixed lattice constant of the spherical crystal,it is difficult to apply the spherical crystal in high-energy X-ray imaging.In this study,we have developed a high-energy,high-resolution X-ray imager based on a toroidal crystal that can effectively correct astigmatism.We prepared a Ge<511>toroidal crystal for backlighting Mo Kα1 characteristic lines(∼17.48 keV)and verified its high-resolution imaging ability in high-energy X-ray region,achieving a spatial resolution of 5–10μm in a field of view larger than 1.0 mm.

High-resolution X-ray flash radiography of Ti characteristic lines with multilayer Kirkpatrick–Baez microscope at the Shenguang-ⅡUpdate laser facility

High-resolution X-ray flash radiography of Ti characteristic lines with a multilayer Kirkpatrick-Baez microscope was developed on the Shenguang-Ⅱ(SG-Ⅱ)Update laser facility.The microscope uses an optimized multilayer design of Co/C and W/C stacks to obtain a high reflection efficiency of the Ti characteristic lines while meeting the precise alignment requirement at the Cu Kα line.The alignment method based on dual simulated balls was proposed herein,which simultaneously realizes an accurate indication of the center field of view and the backlighter position.The optical design,multilayer coatings,and alignment method of the microscope and the experimental result of Ti flash radiography of the Au-coned CH shell target on the SG-Ⅱ Update are described.